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User's Manual

BBS users manual version 1.7


> Introduction

> Setting up the control systems

          Starting a VISTA control window on an Xterminal or an Alpha station

          Starting a PC BITBUS control window

> Magnet control

          Magnet control setting

          Magnet control reading

          Magnet control calculating

> Target control

          Target control setting

          Target control reading

          Target control calculating

> Slit control

          Slit control setting

          Slit control reading

          Slit control calculating

> Diaphragm control

          Diaphragm control setting

          Diaphragm control reading

          Diaphragm control calculating

> Beam stop control

          Beam stop control setting

          Beam stop control reading

          Beam stop control calculating

> Scattering angle control

          Scattering angle setting by local control

          Scattering angle setting by remote control

          Scattering angle reading

> Vacuum control

          Section valves

          Venting and evacuating the scattering chamber

          Venting and evacuating the magnet chambers

          Venting and evacuating the detection chamber

Detector pressure control

         CSC and PPAC Pressure Control system

         Filling the CSC detectors

         EuroSuperNova Pressure Control system

> Interlocks matrix

> Trouble shooting

          HEB Beam stop cannot be removed

          Interlock for a magnet power supply cannot be reset

          Control for target and slit/wheel movements run crazy

          Vacuum alarm in one of the sections

          Beam but no events in your detector system

> Switching off the BBS

 

Caution: NOTE: In some cases control of equipment should be done with extreme care; this is indicated in this manual using the exclamation CAUTION. The user should carefully read such warnings before proceeding.

Introduction

The controls for the BBS are still under development. So is this document. Many things still have to be done including finding bugs and missing items in this "manual". Please send comments to BERG@KVI.NL.

There are known bugs listed in the Dutch documentation BBS Onderhouds werkzaamheden. Please check these lists as well if you find obscure situations.

Setting up the control systems

Some of the controls are already in the VISTA control system running on the KVICS6 VAX computer, other controls (read-outs mainly) are available only through TV camera's or through a rather simple PC program controlling BITBUS stuff.

Local control and most resetting take place in one of the four cabinets on the support of the BBS. These cabinets are numbered as CAB064, CAB065, CAB066, and CAB067. Their location is indicated in a schematic top-view drawing.

Figure 1

Starting a VISTA control window on an Xterminal or an Alpha station

The VISTA display and control system has been installed on two DEC computers. One of these is the KVICS6 computer. Therefore, to use the VISTA system one has to login on this computer either using on Xterminal or using a workstation. To run the VISTA system on a workstation perform the following steps.

  1. On the login window select:
    Option
    Session
    Decwindow session
  2. Login in as:
    username: CS_BBS
    password: PASSWORD
  3. Connect to KVICS6:
    SET HOST /LAT KVICS6
    username: CS_BBS
    password: PASSWORD
    SET DISPLAY/CREATE/NODE=your_node/TRANSFER=TCPIP
    DECW$SESSION
  4. Several windows will now appear on the screen. The most important one being the MAIN MENU. If it does not show up click in the ICON BOX on MENU01.
main menu

Select window MAIN MENU and within the column BBS click on the different entries, which for the case of the BBS are listed in the following table.

field description
INTERLOCKS shows and acknowledges the interlocks
VACUUM displays vacuum conditions
MAGNETS monitor and set DC power supplies of magnets
DETECTOR GAS RECYCLER gas control system for detectors
LOGGING data logging (not used)
SNAP RESTORE save and restore data (not used)

Starting a PC BITBUS Control Window

Make sure you have a PC with a BITBUS card and the software necessary to run the BBS control (ask Ad van den Berg).

Connect the BITBUS cable between the BITBUS patch panel mounted in the back of CAB065 to the PC (either local or remote). The BITBUS patch panel is the one but lowest in the back of this cabinet. To run the program and to load the data base for (stepping) motors and encoders perform the following steps.

1. boot the PC

2. type: CD C:\BBS
    type: MINICON
    type: "CNTRL" F4
    type: "TAB" "TAB" DATABASE.DSK

Where the file DATABASE.DSK can be one of the files listed in the following table.

file

used for

TARGET.DSK

target control

SV.DSK

slits vertical control

SH.DSK

slits horizontal control

ANGLE.DSK

spectrometer angle

WHEEL.DSK

diaphragm wheel control

BS.DSK

beam stop control

 

Magnet control

The BBS has three magnets: two quadrupole magnets and one dipole magnet. Each magnet can be excited only in its main component; there are no multipole components that can be excited individually. The three power supplies of these magnets are located in the basement of the experimental area.

Magnet control setting

Caution: Be careful while changing the current in the dipole (especially at a scattering angle of zero degrees). At zero degrees the direct beam enters into the dipole magnet and changing the field strength of this magnet may cause serious damage to detector systems or other pieces of equipment.

The control of the current through the coils of the magnets is being done using the VISTA control system. To use it open a session using the CS_BBS account. In window MAIN MENU there is an icon called BBS MAGNETS. Open this window and you'll see (from bottom to top) the current status of Q1, Q2 and D1 (these are the two quadrupole magnets and the dipole magnet, respectively). For each magnet two numbers are displayed: the set-value of the current in units of Ampere and below this the read-value of the power supply also in units of Ampere.

BBS Magnets

There are two options to change the set-value.

  1. Click on "DAC", this displays a ruler with two pointers; you may grab the big pointer with the mouse and drag it along the ruler. The little triangle follows slowly and gives the read-value. You may also click on the "+" or "-" icons, which will increase or decrease, respectively, the set-value by one step. The size of the step is displayed if you click the center mouse button on the "+" or "-" icons. This also allows you to modify the value of the step size. The default value for the step is 1.0 A. Click on "EXIT" in the DAC window when your done.
BBS D1 dac

Caution: The DAC window should be closed once you are done with setting the current; leaving it open on the screen makes you vulnerable for unwanted changes of the DAC setting (e.g. somebody accidently hitting the RETURN key).

2. Click with the mouse on the set-value listed next to the DAC value you want to change. A VDRAW window is displayed in which you can edit the set-value. Click on "APPLY" when you're done or on "CANCEL" when you don't want make any change.

Vdraw

Caution: The DAC window should be closed once you are done with setting the current; leaving it open on the screen makes you vulnerable for unwanted changes of the DAC setting (e.g. somebody accidently hitting the RETURN key).

NOTE: While changing the current of the magnets, the power supply for the magnet may run out of its stability loop. This may show up as an interlock failure in the BBS Interlocks matrix. Click on the "ACK ALL" button of the BBS Interlocks matrix and the power supply will reset.

Magnet control reading

Each magnet (Q1, Q2 and D1) has a probe, which is used to read out the field strength at the tip of the poles. The values are displayed on GROUP3 Tesla meter modules for Q1 and Q2 and a METROLAB module for D1, respectively. These modules are mounted in CAB065. Presently a TV camera is being used to display the values in the control room. The TV monitor screen displays the value for Q1 (upper left), Q2 (upper right), and D (lower). All values are in Tesla. Multiply the value of D with 2.20 (central orbit radius) to get the central Brho value in units of Tm.

The METROLAB unit also displays whether the NMR signal is locked; i.e. whether it found a stable dipole field strength for which the read-out can be trusted. The status of this locking signal is also displayed in the Interlocks Matrix.

  1. Push the button "SEARCH/LOCAL" on the METROLAB unit until the red light "REM/SEARCH" is off.
  2. Switch the knob "MPX" to position "A" (0.7 to 2.1 T) or to position "B" (0.35 to 1.05 T). Push again the button
  3. "SEARCH/LOCAL" until the red light "SEARCH/LOCAL" is on.

The field probe for the dipole has two ranges; from 0.35 to 1.05 T or from 0.7 to 2.1 T. The probe can be selected on the METROLAB module mounted in the NIM crate in CAB065. To select and activate a probe do the following.

If the magnet is powered, the field will automatically lock and the green light "NMR LOCK" should be on.

NOTE: After changing the field strength of the magnets it will take some time (until 20 minutes) to reach a stable tip value, this holds especially for the dipole.

Magnet control calculating

At this moment there is a rather simple program that you can use to calculate settings for two-body reactions. Using account CS_BBS, type in a Decterm window SETBBS and the program will start asking some questions. These concern the usual input needed for two-body kinematics. Settings are calculated for the BBS in mode B and for the nominal values of Q1, Q2 and D. So if you want the particles to arrive at the center of the focal plane in the BBS answer the questions as follows:

Enter delta (= dp/p_o) (%) 0.0

Enter correction for Q1 (%) 0.0

Enter correction for Q2 (%) 0.0

Changing delta will cause the particles to go

LEFT = High Momentum Side (delta positive) or

RIGHT = Low Momentum Side (delta negative).

Correction factors for Q1 and Q2 range typically between -10 to +10 (i.e. changes of 10% with respect to the nominal value). Using correction (fudge) factors for the Q1 and Q2 strength will change the focussing properties of the spectrometer! The code lists the Tip field SETTINGS in MODE B. To get the desired field strengths one has to set the DAC values of the DC current through the coils of the magnets. These DAC values are listed as I1, I2 and I3 for Q1, Q2 and D, respectively. The values listed as PROBE should more or less correspond to the reading of the tip fields using the probes mounted inside the magnets.

Target control

Using the Scanditronix Scattering Chamber (SSC) or the Neutron Scattering Chamber (NSC) allows for a remote control of target height and target angle inside the scattering chamber.

Target control setting

Caution: Before changing the target position ask the operator to intercept the beam.

For the target control two stepping motors are being used which can be controlled through a PC running with a BITBUS card inside. Under normal circumstances the PC is hooked up to the BITBUS hardware at the spectrometer and you can run the MINICON program on the PC to move the target positions. First be sure the program on the PC is running and that you have a connection to the hardware at the spectrometer. The display should show you the panels listed and explained in the following table.

panel identifier used for
upper left TG1H control stepping motor target height
lower left TG1H.ENC absolute read out target position (1/1000 mm)
upper right TG1A control stepping motor target angle
lower right TG1A.ENC absolute read out target angle (1/100 degr)

To change the target height or the target angle use the "F6" button to highlight the upper left or the upper right window, respectively. Then type V to call the "Move" window. Use the "TAB" button to skip from one entry to the next. In entry "Value" type the number of steps to be changed (positive or negative). Usually you change relative to the current setting, so "TAB" to "Move Absolute/Relative" and use the up or down arrow to select "RELATIVE".

Target control reading

The read-out of the target height and angle is available on two of the Diegon units labeled as BBS.TG1HENC and BBS.TG1AENC, respectively. These units are mounted in CAB065. While running the MINICON program the lower panels display the actual values of the target height and the target angle. These values are updated if the panels are highlighted; use the "F6" button to do this. The values displayed are in 1/1000 mm and in 1/100 degr.

Target control calculating

Height

131303
Each step corresponds to a change of 0.0083 mm; 10 mm requires therefore 1200 steps; a small KVI target (20 mm height) requires 2400 steps. Usually a ZnS target is in the lower position; this should give a reading at a height of 80000 units (i.e. 80.000 mm). A KVI target ladder can hold five small (20 mm height) targets. Therefore in addition to the ZnS target one can mount four targets. Of course the correct height might be verified with a telescope which is mounted on the back of the BBS. An example for a list of target heights is given in the table.

Angle

Each step corresponds to 0.05 degrees; 10 degrees requires 200 steps; 180 degrees 3600 steps. For clockwise movement the reading should increase. If the target should be perpendicular to the beam direction the read-out should be 000 (0.00 degrees). The target ladder has two pins fitting in holes of the target ladder platform. At a reading of 000 the pins are downstream with respect to the target center.

131517

The target angle with reading 0.000 degrees is shown below; note

  • the beam direction and the location of the holes for the pins,
  • that a clockwise movement increases the reading.

Slit control

The BBS has four slits that can be moved independently. Two slits define the vertical acceptance (slit TOP and slit BOTTOM) and two slits define the horizontal acceptance (slit LEFT and slit RIGHT).

Slit control setting

The movement of the slits is done by four stepping motors that can be activated using the PC running with a BITBUS card. Be sure the MINICON program on the PC is running and that you have a connection to the hardware at the spectrometer. The databases needed are SH.DSK (for slits LEFT and RIGHT) or SV.DSK (for slits TOP and BOTTOM).

Defining the vertical acceptance

After loading the SV.DSK database the display should show you the panels listed and explained in the following table.

panel identifier used for
upper left S1T control stepping motor slit TOP
lower left S1T.ENC absolute read out slit TOP position (1/1000 mm)
upper right S1B control stepping motor slit BOTTOM
lower right S1B.ENC absolute read out slit BOTTOM position (1/1000 mm)

To change the slit position for TOP or BOTTOM use the "F6" button to highlight the upper left or the upper right window, respectively. Then type V to call the "Move" window. Use the "TAB" button to skip from one entry to the next. In entry "Value" type the number of steps to be changed (positive or negative). Usually you change relative to the current setting, so "TAB" to "Move Absolute/Relative" and use the up or down arrow to select "RELATIVE".

Defining the horizontal acceptance

After loading the SH.DSK database the display should show you the panels listed and explained in the following table.

panel identifier used for
upper left S1L control stepping motor slit LEFT
lower left S1L.ENC absolute read out slit LEFT position (1/1000 mm)
upper right S1R control stepping motor slit RIGHT
lower right S1R.ENC absolute read out slit RIGHT position (1/1000 mm)

To change the slit position for LEFT or RIGHT use the "F6" button to highlight the upper left or the upper right window, respectively. Then type V to call the "Move" window. Use the "TAB" button to skip from one entry to the next. In entry "Value" type the number of steps to be changed (positive or negative). Usually you change relative to the current setting, so "TAB" to "Move Absolute/Relative" and use the up or down arrow to select "RELATIVE".

Slit control reading

The read-out of the slit positions is available on the upper four Diegon units labeled as BBS.S1TENC, BBS.S1BENC, BBS.S1LENC and BBS.S1RENC for slits top, bottom, left and right, respectively. These units are mounted in CAB065. While running the MINICON program the lower panels display the actual values of the slit positions. These values are updated if the panels are highlighted; so use the "F6" button to do this. The values displayed are in 1/1000 mm.

Slit control calculating

All slit position read-outs are shown with respect to the center of the entrance in units of 1/1000 mm. To increase the aperture the movement of the slits should be in the positive direction; this holds for each slit. The top and bottom slits are prevented by a micro-switch to cross the mid-plane. The horizontal slits can be moved across the center of the spectrometer. Also in this case micro-switches limit the range of the slits. If the upper (lower) limit is reached the display shows EL+ (EL-), and any further movement in the positive (negative) direction is prevented.

In mode B of the BBS the front face of the horizontal slits (LEFT and RIGHT) are mounted 883 mm downstream of the target position. An opening of 10 mm therefore corresponds to an angle of 0.65 degrees or 11.3 mrad. The front face of the vertical slits (TOP and BOTTOM) are mounted at a distance of 850 mm downstream of the target position. An opening of 10 mm in this case corresponds to an angle of 0.67 degrees or 11.8 mrad.

Diaphragm control

The BBS has a wheel into which four different diaphragms can be mounted. By rotating the wheel, different diaphragms can be selected. Exchange of a diaphragm can be done by venting the scattering chamber and moving the slot for the diaphragm in front of the lucent flange of the slit house.

Diaphragm control setting

Caution: Before changing the diaphragm position ask the operator to intercept the beam.

The movement of the diaphragm wheel is done by a stepping motor that can be activated using the PC running with a BITBUS card. Be sure the MINICON program on the PC is running and that you have a connection to the hardware at the spectrometer. The database needed is WHEEL.DSK.

After loading the WHEEL.DSK database the display should show you the panels listed and explained in the following table.

panel identifier used for
upper DW1 control stepping motor diaphragm
lower DW1.ENC absolute read out diaphragm position

To change the position of the wheel use the "F6" button to highlight the lower window. Then type V to call the "Move" window. Use the "TAB" button to skip from one entry to the next. In entry "Value" type the number of steps to be changed. Usually you change relative to the current setting, so "TAB" to Move Absolute/Relative and use the up or low arrow to select RELATIVE.

NOTE: The MINICON program is known to crash while making such a large number of steps; therefore make several steps of e.g. 4000 steps. In case the MINICON crashes the wheel will stop its movement when it reaches end switches. However, the stepping motor has lost its counts on steps after rebooting the MINICON program.

Diaphragm control reading

143151

The read-out of the diaphragm position is available on one of the Diegon units labeled as BBS.DW1ENC mounted in CAB065. At the DW1 window while running the MINICON program, the lower panel displays the actual value of the wheel position. The value is updated if the panels are highlighted; so use the "F6" button to do this. Prior to each experiment a calibration of the readings should be made.

The Diegon read-out is calibrated such that a change of 90 degrees corresponds with a change of 1 unit on the display. Usual diaphragm positions have, on the Diegon display, values close to 1.0, 2.0 and 3.0.

In case of doubt, check that a diaphragm or an empty slot is visible through the lucent flange mounted on the slit house. If a diaphragm or an empty slot is visible, on the opposite side there will also be a diaphragm or an empty slot. If the wheel itself is visible the entrance to the spectrometer will be blocked by the wheel.

Diaphragm control calculating

In mode B of the BBS the front face of the diaphragms are mounted 817 mm downstream of the target position. Standard diaphragms plates are available. These plates have a pattern with 3 or 6 mm diameter holes lined up in rows and columns. The rows are separated by 20.0 mm (vertical angle step is 24.5 mrad), the columns are separated by 10.0 mm (horizontal angle step is 12.2 mrad).

Each step of the stepping motor turning the wheel, corresponds to a change in angle 0.009434 mrad; a 90 degree swing therefore requires 16650 steps. For the nominal radius to the center of the target wheel (r=260.7 mm) each step corresponds to a movement of 0.0246 mm.

Beam stop control

There is a movable beam stopper in between the second quadrupole and the entrance of the dipole. The stopper is moved in the x-direction (i.e. perpendicular to the beam direction).

Beam stop control setting

The movement of the beam stopper is done by a stepping motor that can be activated using the PC running with a BITBUS card. Be sure the MINICON program on the PC is running and that you have a connection to the hardware at the spectrometer. The database needed is BS.DSK.

After loading the BS.DSK database the display should show you the panels listed and explained in the following table.

panel identifier used for
upper BS2 control stepping motor beam stop 2
lower BS2.ENC absolute read out position beam stop 2

To change the position of the beam stop use the "F6" button to highlight the lower window. Then type V to call the "Move" window. Use the "TAB" button to skip from one entry to the next. In entry "Value" type the number of steps to be changed. Usually you change relative to the current setting, so "TAB" to Move Absolute/Relative and use the up or low arrow to select RELATIVE.

Beam stop control reading

The read-out of the position of the beam stop BS2 is available on one of the Diegon units labeled as BS2.DW1ENC mounted in CAB065. At the BS2 window while running the MINICON program, the lower panel displays the actual value of the beam stop position. The value is updated if the panels are highlighted; so use the "F6" button to do this. Prior to each experiment a calibration of the readings should be made.

The Diegon read-out is calibrated in mm, where the 0 is the low-momentum side (i.e. towards the return yoke of the dipole magnet) and the full swing is about 900 mm.

Beam stop control calculating

The thread of the rod is 0.05" per turn, with 200 steps per turn, this gives a change of 0.00635 mm per step, or 157.5 turns per mm. Positive direction is towards the high-momentum of the dipole magnet.

Scattering angle control

Caution: In all cases, be sure the movement you will make does not interfere with other pieces of equipment.

Caution: In all cases ask the operator to intercept the beam prior to making the change.

194543
Some security features have been installed and are as follows:
  1. a brush and shovel on each side of the support to clean the rail of the BBS while moving,
  2. two orange sense switches which limit the angular range of the BBS (e.g. to protect detector systems or bellows of the scattering chamber).

In case a shovel senses something on the rail a micro-switch is triggered preventing any movement of the BBS. Check the cause of the failure and use the "ACK ALL" button on the BBS Interlocks window in VISTA or the "Interlock Ack&Clear" button on the Interlock Control Panel in CAB066. Sometimes the micro-switch is tripped without any obvious reason. Put the "shovel" straight and push the "ACK ALL" button or "Interlock Ack&Clear" again.

The orange switches can be tripped by one of the clamps mounted on the cover of the rail used for the read-out of the angular encoder. In case one of these orange sense switches is triggered, it means you have reached the limit of the range of the BBS. To move the BBS in the other direction, switch to the local control of the support and press the "BYBASS" and the "<" (or ">") buttons simultaneously to release the orange sense switch. Having reached the normal range again, push the "Interlock Ack&Clear" button of Interlock Control Panel in CAB066.

Scattering angle setting by local control

The scattering angle can be controlled at the Support Drive Local Control Panel in CAB066 or through a PC using BITBUS interfacing and the MINICON program. In both cases do the following steps.

  1. Ask the operator to intercept the beam.
  2. Close SKS2 (beamline valve) and SK1 (BBS valve).
  3. Switch the key on the Support Drive Local Control Panel in CAB066 to "ON" (if not done already).
  4. Use the push buttons on the Support Drive Local Control and the Interlock Control Panel in CAB066 for local control or for remote control using the PC ("remote" still being inside the area).
  5. For local control on the Local Control Panel:
    • push button "LOCAL" on the Support Drive Local Control Panel;
    • push button "Interlock Ack&Clear" on the Interlock Control Panel;
    • push button ">" or "<" on the Support Drive Local Control Panel, during movement a beeper should be heard;
    • in case the movement finishes before the desired value has been reached one of the safety switches has been triggered;
    • after reaching the desired value push button "OFF" on the Support Drive Local Control Panel.
  6. For remote control with a "local" PC:
    • push button "LOCAL" on the Support Drive Local Control Panel;
    • push button "REMOTE" on the Support Drive Local Control Panel;
    • push button "ACK ALL" on the BBS interlock matrix in VISTA or the button "Interlock Ack&Clear" on the Interlock Control Panel;
    • load database ANGLE.DSK in the MINICON program;
    • move BBS to the desired value; the value to be entered should be in units of 1/100 degree (e.g 10 degrees should be entered as Value 1000 and Move ABSOLUTE); during movement a beeper should be heard;
    • in case the movement finishes before the desired value has been reached one of the safety switches has been triggered;
    • after reaching the desired value push button "OFF" on the Support Drive Local Control Panel.
  7. Open section valves SKS2 and SK1.

Scattering angle setting by remote control

DON'T YOU DARE !

Scattering angle reading

The read-out of the scattering angle is available on one of the Diegon units labeled as BBS.ANGENC mounted in CAB065. It displays the value of the scattering angle in degrees to an accuracy of 0.01 degree. At the ANG window while running the MINICON program the scattering angle is displayed in units of 1/100 of a degree.

Vacuum control

The vacuum system is separated by section valves into three different compartments. These valves are:

  • for the scattering chamber SKS2 (beamline) and SK1 (BBS)
  • for the magnet chamber SK1 and SK2 (BBS)
  • for the detector chamber SK2 (BBS)

For each section a control system is available to keep the pressure inside the chambers to an intermediate pressure (< 2E-4 mbar). To do this for each section, three different pump units can be operated simultaneously; e.g. for the magnet chambers there are three large diffusion pumps (each one having its own backing pump) hooked up to the chamber.

bbs vacuum
Each pump unit consists of:
  • one backing pump;
  • one turbomolecular or diffusion pump;
  • one Pirani gauge mounted in the backing line plus a local read-out unit;
  • one backing valve;
  • one local Pump Control Panel.

The local Pump Control Panels are mounted below the local Vacuum Control Panels in CAB067, CAB064 and CAB066 for the scattering chamber, the magnet chambers and the detection chamber, respectively.

Each section has its own local Vacuum Control Panel. This control panel indicates the status of:

  • each pump unit (upto three different units);
  • each pumping valve PKi-1 to PKi-3 (i=1..3);
  • the section valves SKS2, SK1 and/or SK2;
  • the venting valve VKi (i=1..3);
  • the roughing valve RKi (i=1..3);
  • the read-out of a Pirani and Penning gauges (TVi and PVi, i=1..3, respectively);
  • the status of the compressed air supply (storing perslucht).

The local Vacuum Control Panels 1, 2 and 3 are found in CAB067, CAB064, and CAB066 for the scattering chamber, the magnet chamber and the detection chamber, respectively. The overall vacuum status of the whole BBS is shown on the Vacuum Control Panel mounted in CAB065; on this panel one can open and close the section valves.

One PLC (type ABB ZE 86 or ABB UCZA) reads out the status of each pump unit (9 units in total + 3 spare units), the compressed air status and the transmitter signals of the Pirani and the Penning gauge for each vacuum section. For each section the status of the vacuum system can be displayed using the VISTA control system; use window BBS VACUUM of the MAIN MENU. For each section the following items are displayed:

  • the read-out values of the Pirani gauges for the scattering chamber, the magnet chamber and the detector chamber (TV1, TV2 and TV3, respectively);
  • the read-out values of the Penning gauges for the scattering chamber, the magnet chamber and the detector chamber (PV1, PV2 and PV3, respectively);
  • the status of the pump units (a green bar indicates status pump unit is OK, a yellow bar indicates pump unit failure);
  • the status of the pumping valves PKi-1..PKi-3 (i=1..3);
  • the status of the roughing and venting valves for the scattering chamber and the magnet chamber.

Note that the displayed values for the pressure inside the vacuum compartments are listed as 10LOG(value) of the pressure in mbar. So typical values during normal operating conditions should be less than -4.0. In case the Penning gauge reaches a value higher than 2E-4 mbar (reading -3.7), the section valves for this chamber close and one has to search for the cause of the in-leak into this section.

Section valves

The local control of the section valves is mounted in CAB065. To open a section valve push simultaneously the push button for the section valve and the "AAN/OPEN" button. To close a section valve push simultaneously the push button for the section valve and the "UIT/DICHT" button.

Note that a section valve can be opened only if the red LED's indicating the status of the Penning gauges (PV) are not on. In case a red LED is blinking try to reset the error by pushing the "RESET" button on the control panel.

Also with the VISTA control system the section valves can be opened and closed. An open valve is indicated as a black-and-white bow-tie display; a closed valve as a yellow bow-tie display. In case the valve is open nor closed the display shows a yellow-and-black bow-tie. To open or close a section valve click on the little square box next to the valve. Blinking red LEDs either for PVi or TVi (i=1..3) indicate a vacuum error.

Venting and evacuating the scattering chamber

This recipe holds only for the Scanditronix Scattering Chamber or its derivatives (e.g. the Neutron Scattering Chamber).

ssc_vac

1. Close SKS2 and SK1 on the BBS Vacuum Control Panel in CAB065 or with VISTA window BBS VACUUM.

2. Close pumping valve PK1-1 in CAB067 by pushing the button "UIT/DICHT" and button "PK1-1" simultaneously on Vacuum Control Panel 1.

3. Move targets perpendicular to the beam direction.

4. Open slowly the venting valve VK1; watch the pressure reading.

5. Open the lid and change targets.

6. Close the lid.

7. Connect a movable pump unit to the roughing valve RK1.

8. Close the venting valve VK1.

9. Switch on the VVP of this movable pump and open slowly (!) the roughing valve RK1; watch the pressure go down.

10. At 100 mbar switch on the roots pump of the movable pump as well.

11. Wait until the Pirani reading is below 0.02 mbar (display TV on Vacuum Control Panel 1 in CAB067) and reset TV1 by pushing the "RESET" button.

12. Close the roughing valve and open the pump valve PK1-1 by pushing button "AAN/OPEN" and button "PK1-1" simultaneously on Vacuum Control Panel 1.

13. If the penning pressure (display PV1 on Vacuum Control Panel 1) is below 2E-4 mbar push again the "RESET" button and open SKS2 of the beamline and SK1 of the BBS. Note that the penning gauge is protected against bad vacuum conditions. It may take a couple of minutes before it ignites.

14. Move targets to the desired target angle.  

Venting and evacuating the magnet chambers

The section valves are designed such they can be used properly while the pressure in the magnetic chamber is less than or equal to the pressure in the neighbouring sections (scattering chamber for SK1 and detector chamber for SK2).

Caution: If one wants to vent the magnet chamber, the scattering chamber and the detector chamber should be vented as well!

1. Close section valves SK1 and SK2 on the BBS Vacuum Control Panel in CAB065 or with VISTA window BBS VACUUM.

2. Close pumping valves PK2-1, PK2-2 and PK2-3 on Vacuum Control Panel 2 in CAB064 by pushing simultaneously the button "UIT/DICHT" and the buttons "PK2-1", "PK2-2" and "PK2-3".

3. Open the venting valve VK2; complete venting will take three hours!

4. Having finished the work to be done close the venting valve VK2.

5. Connect a movable pump unit to the roughing valve RK2.

6. Switch on the VVP of this movable pump and open the roughing valve; watch the pressure go down.

7. At 100 mbar switch on the roots pump of the movable pump as well.

8. Wait until the Pirani reading is below 0.02 mbar (display TV on Vacuum Control Panel 2 in CAB064) and reset TV2 by pushing the "RESET" button.

9. Close the roughing valve and open the pump valve PK2-1, PK2-2 and PK2-3 by pushing button "AAN/OPEN" and buttons "PK2-1", "PK2-2" and "PK2-3" simultaneously on Vacuum Control Panel 2.

10. If the penning pressure (display PV2 on Vacuum Control Panel 2) is below 2E-4 mbar push again the "RESET" button and pump down the scattering chamber and the detection chamber. Note that the penning gauge is protected against bad vacuum conditions. It may take a couple of minutes before it ignites.

Venting and evacuating the detection chamber

The vacuum control depends on the fact whether or not there are gas-filled detectors inside the vacuum chamber. Therefore two different cases will be discussed; the gas-filled detector case and the NOT gas-filled detector case.

I. Control of vacuum while gas-filled detectors are inside

Caution: If one wants to vent the detection chamber, and if there are detectors inside one has to vent and evacuate the detection chamber simultaneously with these detectors. While doing so, the pressure of the detectors should remain higher than the pressure of the detection chamber.

NOTE: In case of panic push the red STOP button on the CSC/PPAC Detector Pressure Control Box.

A PLC-based control system is available to monitor the differential pressure of two independent detector systems (e.g. IPN-Orsay made CSC and PPAC systems). The control system also acts as a watch dog in case differential pressures are too high (explosion danger) or too low (implosion danger). For details see the section CSC and PPAC Gas and Pressure Control System.

BBS DET

The differential pressures P2 (for CSC) and P3 (for PPAC) can be monitored using the VISTA control or with two Digital Volt Meters. These DVM's are mounted in the back of CAB065 and have a conversion gain as listed in the following table.

detector number mbar/V
CSC P2 120
PPAC P3 1.32

The venting sequence is as follows.

  1. Push the red button on the CSC gas-control cabinet; this forces valves 7 and 8 to close.
  2. Hook a bottle of argon to the venting valves 6 and 9 of the detectors, in this way the detectors will be filled with argon.
  3. Close section valve SK2.
  4. On the CSC/PPAC Detector Pressure Control Box push button "VENT"; i.e. PLC state = VENTING. The button "VENT" on the CSC/PPAC Detector Pressure Control Box will be flashing.
  5. The PLC will now vent the detectors and the vacuum box while keeping the differential pressures P2 and P3 in a safe regime. The PLC will open valves 6 and 9 for venting the detectors, valve 1 for venting the vacuum chamber and valve 2 and 3 if the differential pressures go out of range.
  6. The end of the vent procedure is reached when the vacuum chamber is slightly below atmospheric pressure and both detectors are still at an overpressure. At that stage the PLC state will be VENTED and valves 1, 2 and 3 remain open (these are the venting valve of the vacuum chamber, and the two shorting valves, respectively). The button "VENT" on the CSC/PPAC Detector Pressure Control Box will remain lit.

    NOTE: For security reasons don't forget to close the manual valves of all gas bottles (the ones used for flushing the detectors with gas during operation as well as the argon bottle used for venting).

Caution: During the pump-down procedure one should note the following. Automatically, valve 5 will open if the pressure in the vacuum chamber drops below 500 mbar; be careful and adjust the pumping speed using the manual valve between the vacuum chamber and valve 5; in any case don't run away but watch the dvm's.

NOTE: In case of panic push the red "STOP" button on the CSC/PPAC Detector Pressure Control Box.

Caution: The user should verify that opening valves 10 and 11 will cause no harm to the PPAC or the CSC detector systems.

After having taken care of the above mentioned safety procedures the pump-down sequence is as follows.

  1. Connect a movable pump unit to the roughing valves (valves 4 and 5).
  2. Switch on the VVP of this movable pump (both roughing and roots).
  3. Close the manual valve between the vacuum chamber and valve 5.
  4. Push the red "STOP" button on the CSC gas-control cabinet. To unlock this button rotate it slightly. Then push "STOP" on the touch screen panel.
  5. On the touch screen of this gas-control cabinet push "AUTOMATIC" and "ARGON/ETHANE" or "ISOBUTANE".
  6. On the CSC/PPAC Detector Pressure Control Box push button "PUMP"; i.e. PLC state = PUMPING. The button "PUMP" on the CSC/PPAC Detector Pressure Control Box will be flashing.
  7. Pressure P1 which is the pressure just above the VVP will drop and automatically valve 4 will open; this is a small valve causing a reduced pumping speed! The read-out of this meter can be found underneath the BBS Vacuum Panel 3 in CAB066.
  8. Gently open the manual valve between the vacuum chamber and valve 5.
  9. Pumping down of the vacuum chamber will proceed through valve 4; the detectors are pumped down through the shorting valves 2 and 3 while keeping the differential pressure in a safe region. It should be noted here that the differential pressure of the CSC's and the PPAC only starts to deviate from 0 mbar, if you are already pumping for quite some time. At a vacuum chamber pressure of 500 mbar valve 5 will open.
  10. The end of the pump-down procedure is reached if the vacuum in the detector chamber is OK (LED TV3 can be reset on the Local Vacuum Control Panel 3 in CAB066), and the differential pressures in the detectors are in a safe regime. The roughing valves 4 and 5 close and pumping valves PK3-1 and PK3-2 open. Initially, the backing pressure of pumps 3-1 and 3-2 can be too high. Because of this a pumping valve might close and the pump will be switched off. One can reset this by pushing the "RESET" button on the control panel for the pump that switched off. If one can reset, switch on the pump by pushing simultaneously the buttons "AAN" and "TP-DP" after which the pumping valve will open again. It might be needed to repeat these steps several times; while doing so keep an eye on TV3 and the backing pressure of these pumps. To open the valves 10 and 11 for the PPAC push button "PPAC" on the CSC/PPAC Detector Pressure Control Box. At this point the PLC state will be PUMPED which means all pressures OK. The button "PUMP" on the CSC/PPAC Detector Pressure Control Box will remain lit.
  11. Switch off the roughing pump and disconnect it from the roughing line.
  12. You are now ready to fill the detectors

II. Control of vacuum while no gas-filled detectors are inside

Open the back side of cabinet CAB064 and set switch CSC and switch PPAC to DISABLE. Push the red STOP button on the CSC/PPAC Detector Pressure Control. In this way, the PLC acknowledges that there will be no detector inside the chamber and pumping can proceed through the BBS Vacuum Control Panel 3 mounted in CAB066.

The pump-down sequence is as follows:

  1. Connect a movable pump unit to the roughing valves (valves 4 and 5).
  2. Switch on the VVP of this movable pump (both roughing and roots).
  3. Close the manual valve between the vacuum chamber and valve 5.
  4. Pressure P1, which can be read underneath the Vacuum Control Panel 3, will drop, indicating that the pump is running.
  5. On the BBS Vacuum Control Panel 3 push simultaneously the button "AAN/OPEN" and the button RK3.
  6. Slowly open the manual valve to allow the chamber to be pumped down.
  7. If the LED TV3 can be reset on the Vacuum Control Panel 3 (this is the case when the pressure is smaller than 2E-3 mbar), close the roughing valve by pushing simultaneously the button "UIT/CLOSE" and the button RK3.
  8. Finally open the pumping valve(s) PK3-1 (and PK3-2 if this is mounted) by pushing simultaneously the button(s) "AAN/OPEN" and the button(s) PK3-1 (and PK3-2).
  9. Switch off the VVP of this movable pump (both roughing and roots).

The venting sequence is as follows:

  1. Close the pumping valve(s) PK3-1 (and PK3-2 if this is mounted) by pushing simultaneously the button(s) "UIT/CLOSE" and the button(s) PK3-1 (and PK3-2).
  2. On the BBS Vacuum Control Panel 3 push simultaneously the button "AAN/OPEN" and the button VK3.

Detector pressure control

There are two different control systems available; one pressure control for the CSC and PPAC systems, the other pressure control for the EuroSuperNova system.

 

I. CSC/PPAC Detector Pressure Control System

BBS DET

Caution: Pushing the button "STOP" on the CSC/PPAC Detector Pressure Control Box will cause the bypass valves 2 and 3 to open and all other valves 1 to 11 to close. Immediately the gas inside the detectors will flow into the vacuum forcing many vacuum valves to close; this is a real panic button.

Caution: Pushing the button "PPAC" while it is lit will open valves 10 and 11. Immediately gas will flow into the ppac and the user should check that it is safe to do so.

This control system has been developed for the following purpose:

The watch dog function is relatively simple; i.e. in case the differential pressure in ANY detector during ANY state of operation reaches the explosion limit (high alarm limit) or the implosion limit (low alarm limit) the shorting valves 2 and 3 of the detector system open. This will equilibrate the differential pressure between the detectors and the vacuum chamber. In addition to these alarm limits there are working limits which act as a pre-warning system to prevent reaching the implosion or explosion limits. If the differential pressure for any detector goes outside the working limit the system forces the control into the STANDBY situation (all valves closed).

The alarm and working limits can be viewed using the VISTA control by clicking on the "SETPOINTS" button in the BBS DET window.

BBs detector

The PLC has several states and if allowed one can go to the different states of the control system. Sometimes changing of a state will go automatically, in other cases the user can try to force the system into another state with the CSC/PPAC Detector Pressure Control Box.

These are the main states and their way out.

  1. VENTING
    The detectors and the vacuum chamber are being vented. From here one can go to VENTED, PUMPING, PUMPED, STANDBY, STOP.
  2. VENTED
    The detectors and the vacuum chamber are vented, one can remove the lid of the vacuum chamber and disconnect the gas lines. From here one can go to PUMPING
  3. PUMPING
    The detectors and the vacuum chamber are being pumped down. From here one can go to PUMPED, VENTING, STANDBY, STOP.
  4. PUMPED
    The vacuum chamber vacuum is OK (TV3 is below its trip level) and the detectors are within their working range. This is the usual experimental situation. In some case the control forces the system into the STANDBY situation, these cases are:
    • a vacuum failure (TV3 is too high),
    • a CSC gas-control failure (e.g. an empty gas bottle),
    • the differential pressure for either detector is outside the working limit,
    • the read-out of a valve position does not correspond to the wanted value.
    From here one can go to STANDBY, STOP, VENTING.
  5. STANDBY
    Puts the system in a stand-by situation; all valves on all detectors will be closed; these are the:
    • gas in and gas out valves for the CSC (10 and 11),
    • shorting valves (2 and 3),
    • venting valves (6 and 9),
    • valves 1, 4 and 5 of the detection chamber.
    Push the red "STOP" button on the CSC gas control to close valves 7 and 8 for the CSC gas control. From here one can go to VENTING, PUMPING, PUMPED
  6. STOP
    In this state the shorting valves 2 and 3 are open. The differential pressure between the detectors and the vacuum chamber goes to zero by flowing gas from or to the detectors. From here one can go to VENTING and PUMPING.

To operate the CSC/PPAC Detector Pressure Control System one uses the CSC/PPAC Detector Pressure Control Box. This box has six push buttons.

  1. CONTINUE
    Continues operation in case the control or the user forced the system into the STANDBY situation. It should be clear that operation will only continue if all systems are OK; i.e.
    • vacuum OK, check the local Vacuum Control Panel of the detection chamber;
    • CSC OK, check the CSC gas-control cabinet;
    • PPAC OK, push the button "PPAC" on the Pressure Control Box,
    • Differential pressure for each detector is within the working limits.
  2. PPAC
    Signals to the PLC control that the user has established that the gas control of the PPAC is ready and that opening valves 10 and 11 will not jeopardize the systems.
  3. PUMP
    Starts the pump-down procedure.
  4. STOP
    Moves the system into the STOP state.
  5. STANDBY
    Moves the system into the STANDBY state.
  6. VENT
    Starts the vent procedure.

II. Filling the CSC detectors

To fill the CSC detectors use the following procedure.

  1. At the CSC gas-control cabinet set dial SET PT of the MKS controller type 250 to the desired value (in mbar).
  2. Open the manual valves of the gas bottles and adjust the pressure in the gas lines using the appropriate pressure reducers.
  3. On the touch screen push the following 'buttons':
    "AUTOMATIC" followed by
    "ARGON/ETHANE" or "ISOBUTANE".
    On the CSC gas-control touchscreen panel you will see first the pumping down of the gas-in and gas-out lines followed by filling these lines until the desired pressure. If the reading "SYSTEM PRESSURE MBARS" on the touch screen is close to the desired value push "VALID". The detectors will be filled automatically to the desired value. In case the final value is not reached in two minutes, repeat the following steps on the touch screen:
    "AUTOMATIC"
    "ARGON/ETHANE"
    The screen will then tell you you have to do a "pumping" on the vacuum control system. To do this perform the following step using the CSC/PPAC Detector Pressure Control Box:
    push "STANDBY"
    push "CONTINUE"
    and finally push "PPAC"
    On the CSC gas-control touchscreen panel you will see first the pumping down of the gas-in and gas-out lines followed by filling these lines until the desired pressure. If this pressure has been reached push "VALID" on the touch screen panel.
  4. You are ready if the touch screen displays the message "DETECTORS ARE NOW RUNNING".

III. EuroSuperNova Detector Pressure Control System

The EuroSuperNova Detector Pressure Control System has two components: the gas-recycler unit and the gas-distribution system. The gas-recycler unit is mounted in a 19 inch cabinet located near the north-east pillar in the experimental hall. The gas-distribution panel is mounted onto the support structure of the ESN detector system. For each individual detector there are valves to regulate the flow to and from the detector, and a pipe leading to a common pressure meter (called PD371) for all six detectors. Also in the pipe to the common gas-pressure meter there is a valve.

Each detector is protected for under or over-pressure in two different ways. First there is a watchdog on the PD371 pressure read-out; in case this pressure is smaller than 0.08 mbar or higher than 4.7 mbar, the valves at the gas-distribution panel are automatically closed by a PLC. In addition, to this watchdog, there are also oil-filled glass-made bubblers, which protect the chambers for overpressure. These bubblers are mounted on the gas-distribution panel.

In addition to the watchdog on the pressure of the chambers, the gas flow from the gas bottle into the recycler/mixing unit is monitored. In case the buffer tank is being filled from the gas bottles and if during that same time the flow from one of the bottles drops below an adjustable value, a warning will be given by the VISTA control system and the automatic valves at the gas-distribution panel will be closed. In addition, a signal is given to the high-voltage units of the wire chambers and they are all switched off, resulting in warning signals given by the slow-control system of these high-voltage units.

To start the gas flow in the ESN detectors follow the procedure described below.

1. Check, or ask somebody to check, whether there is still gas in the bottles. Open the manual valves of the gas bottles used for the detector system (usually a bottle of argon and a bottle of isobutane).

2. On the gas-distribution panel, open the supply valves 673, 411, 421, 431, 441, 451, and 461 in case all 6 chambers will be used. In case only the VDC's are being used open only valves 673, 451 and 461.

3. Similarly open the return valves 671, 413, 423, 433, 443, 453, and 463 or only valves 673, 453 and 463.

4. Open valve 672; this opens the line between the a small buffer vessel and the gas pressure sensor of the wire chambers.

5. Then proceed to the gas-recycler/mixing cabinet.

6. On this cabinet, close all valves. Check that the switch for the read-out of the gas pressure is set to PD371 (BBS). Open valves VM301, VM330 and VM345. Switch the two-way valve which couples the pressure monitor PD371/BBS or PD372/SALAD to PD371/BBS.

7. Open valves VM201 and VM202 (for argon and isobutane, respectively). and switch FC202 and FC201 on the MKS model 247C unit from remote (REM) to on (ON). The green LED's will light and filling of the buffer tank can start. To reset the watchdog on the gas flow meters, open for a short while the valve VM207; don't forget to close this one and to switch to FC202 and FC201 back to remote!

8. Watch the pressure read-out on sensor BP379, which is displayed on the MKS pressure PDR-5B read-out panel on channel 2. This read-out is the display of a digital-volt meter (DVM), with a range between -10 to +10 V (-13.3 mbar upto +13.3 mbar). In case the read-out of the pressure is out of range (i.e. larger than 10 V), use the read-out on the display mounted underneath the displayed location of the PD371 on the gas-recycler panel.

  • In case the pressure is higher than 4.8 mbar (i.e. 3.60 V on the DVM display), one has to remove gas from the buffer tank. The procedure is as follows. Switch on pump PD371 using the the green switch. Switch on the gas controller FC371. Watch the drop of the pressure. Once the pressure is in range, switch off FC371.
  • In case the pressure is lower than 0.08 mbar (i.e. 0.06 V on the DVM display), one has to bring additional gas into the buffer tank. The procedure is as follows. Open valve VM386. Open the manual flow controller FR344. Watch the increase of the pressure. Once the pressure is in range, close valve VM386 and close the manual flow controller FR344.

9. Push the green button, to open the automatic valves to the detector. These valves remain open, until one pushes again this button or in case the watch dog on the pressure of the detector is out of range.

10. Go the gas-distribution panel.

11. At this panel, set the knobs on the manual flow meters such that for every detectors used, the little red ball, flows around 20. This means the detectors are being filled, and the pressure in each detector increases gradually; the windows start to bulge. For each individual detector one can check the pressure increase by looking at the oil level in glass bubblers. If the balance is about 1 cm, one can open up the valves 412, 422, 432, 442, 452, and 462, which connect the pressure read-out PD371 with every individual channel (of course if only the VDC's are being used, open only 452 and 462).

To stop the gas flow in the ESN detectors, be sure the high-voltage on the detectors is switched off. Then push the green button, close all the valves on the gas-distribution panel and close the valves on top of the gas bottles.

Interlocks Matrix

To allow a safe operation of the BBS equipment an interlock system has been developed. Brute force interlock can be established by pushing the red emergency buttons of the BBS. One is located in the control room, one is located on the South Pillar near the scattering chamber of the BBS, the last one is in the basement near the DC power supplies for the magnets.

BBS Interlocks

The interlocks matrix displays the interlock situation for the BBS control system. The top line of the matrix shows the equipment that is watched by the interlock system. This equipment is:

Failures can be acknowledged and reset by clicking the "ACK ALL" button. Or by pushing the "Interlock Ack&Clear" button on the Interlock Control Panel in CAB066 (see picture 6.1). The user may choose to bypass some of the interlocks with a key on the BBS Interlock Control Panel mounted in CAB066.

Trouble shooting

NOTE: Please record all important errors in the BBS logbook. Appropriate actions can be made to prevent further errors or bugs in the systems (I hope).

HEB Beam stop cannot be removed

This may have several reasons. On the VISTA control click in the MAIN MENU on the BBS interlocks icon. This will show you the Interlocks matrix. For the operator the column BEAM STOPS should give all OK's. In case there is a FAIL, try to reset with the "ACK ALL" button. If this doesn't work you have a problem with one of the following things.

  1. Emergency button; somebody pushed one of the three BBS panic buttons.
  2. Vacuum.
  3. Magnet control or NMR locking.
  4. Cooling water or compressed air (consult experts).
  5. Closed SK1 and SK2.

Interlock for a magnet power supply cannot be reset

In the VISTA MAGNETS window click on Q1, Q2 or D1 to ask for the power supply window. The status of the selected power supply is displayed together with the interlock values. Consult an expert for assistance (the operator to start with).

hEB

I.The control for target and slit/wheel movements run crazy

This usually happens while running with INTERLOCKS not bypassed (the safe way to run anyway, but at this moment still some bugs are to be removed) or when making a large number of steps with a stepping motor. The control is not yet optimal (hm...).

While running properly (interlocks NOT bypassed) you CANNOT operate the slit, diaphragm wheel and/or target positions if there is beam on target. To do this the following trick is being used. A PLC checks if beam stops B and S are in. If these stops are not in the IN position and if this has not been updated in the menu BBS INTERLOCKS the control of the PC will go weird. The PLC tries to stop the movements whereas the PC tries to move them. Eventually the updating of the PC screen degrades and a RUN_TIME_ERROR of the MINICON program on the PC might occur. You cannot move the slits, wheel or target anymore.

To reset this, do the following.

  1. Tell the operator to insert HEB beam stops B and S.
  2. Find the BBS INTERLOCKS window on the VISTA control.
  3. Click the "ACK ALL" button until the interlocks for the movements needed are all OK (e.g. support drive, slits or targets)
  4. If the RUN_TIME_ERROR occurred, the link between the PC and bitbus card in control rack is overloaded. Go to the experimental hall and find CAB067.
  5. Push with a small screw driver the reset button of INCAA model BCON-5350 (the reset is behind the frontpanel in the little hole)
reset
  1. The red LED's of all MSTP's in this rack should be off and the green LED on the BCON module should now be on or flashing.
  2. If this still isn't the case consult an expert and skip the next lines.
  3. Go to the PC and exit the MINICON program (either by "ALT-X" or by rebooting)
  4. Type: MODSCAN
    This program re-initializes the interface to the stepping motors); push "RETURN" several times (when the screen displays "more ... ") to exit this program
  5. restart MINICON.
  6. Reload the DSK file (use "ALT-D" or "CNTRL+F4").
  7. Change the position of the device needed; sometimes if you want to do it with the "MoVe" and "Value" command, it still does not work. Use the "<" or ">" instead; this will work.
  8. To avoid these problems there are two ways.
  9. Check always before changing that HEB beam stops B and S are IN and that you ACKNOWLEDGED it in the BBS interlock window before moving the slits, the target or the wheel.
  10. Remove the interlock safety from the system using the interlock KEY in the Interlock Control Panel in CAB066. The BBS interlock window should now flash the message INTERLOCKS BYPASSED;

Caution: Safety is now up to you! Always ask operator to hold the beam before changing targets!

Vacuum alarm in one of the sections

A vacuum alarm occurs if the pressure in one of the sections is above 2E-4 mbar. This forces the section valves for this section to be closed. At a pressure above 1E-2 mbar or at a backing pressure above 1E-1 mbar also the pumping valves close. On the Vacuum Controls Panels 1, 2 and 3 in CAB067, CAB064 and CAB066 you can check the status of the vacuum pumps. For the scattering chamber there is one turbomolecular pump, for the magnet chamber there are three diffusion pumps and for the detection chamber there are two diffusion pumps. In case of failure a red LED should be blinking on the Vacuum Control Panel of a section.

Sometimes the Penning gauge just transmits a wrong value. In this case the section valve(s) for this vacuum section will close, while the pumping values remain open. However, the Penning read-out shows a rather high value or quite contrary an extremely small value. It may help to ignite the Penning gauge again. Do this by switching off and on the power of the PTR100 transmitters. These transmitters are located near the waterlocks of the various sections; for the scattering chamber on the side of the support near the pivot point; for the magnet chamber behind CAB065; for the detection chamber to the right of CAB066. If the gauge ignites again after switching it off and on, push button "RESET" on the Vacuum Control Panel and open the section valves again.

For the scattering chamber it should be the left most pump unit, which shows the status of the turbomolecular pump (PS1-1). A failure may be caused by a too small waterflow (waterkoeling LED blinks), a too low speed of the pump (80% LED blinks) or a too high backing pressure (TVV LED blinks).

  1. Water cooling failure.
    • If there is a general water cooling failure contact a specialist.
    • If it is one pump only clean the waterflow regulator, reset the pump unit and switch on the pump (press the button "TP-DP" simultaneously with the button "AAN/OPEN")
  2. Too low speed of pump.
    • Check that the pump is still running (lowest unit in CAB067), contact a specialist.
  3. Too high backing pressure.
    • Check that the backing valve is open; if not open it (press button "AAN/OPEN" simultaneously with button "AK"; reset the pump unit and switch on the pump (press the button "TP-DP" simultaneously with the button "AAN/OPEN")
    • If the backing valve is open read the backing pressure of the Thermovac TVV1 mounted in CAB067; it will be larger than 1E-1 mbar; check that the small pump used for the vacuum of the sliding shield is still running, switch on if it is off, reset the pump unit and switch on the turbomolecular pump (press the button "TP-DP" simultaneously with the button "AAN/OPEN")
    • You have a serious leak, contact a specialist.

For the magnet chamber there are three pumping units the status of them being displayed on Vacuum Control Panel 3 in CAB064. In principle one should be able to run with one pump only, but the normal condition is that all three pumps are working properly. A failure may be caused by a too small waterflow (waterkoeling LED blinks), a too low temperature of the pump ( 190 degrees LED blinks) or a too high backing pressure (TVV LED blinks).

  1. Water cooling failure.
    • If there is a general water cooling failure contact a specialist.
    • If it is one pump only clean the waterflow regulator, reset the pump unit and switch on the pump (press the button "TP-DP" simultaneously with the button "AAN/OPEN")
  2. Too low temperature.
    • Check that the pump is still running (Pump Control Panel in CAB064) contact a specialist.
  3. Too high backing pressure.
    • Check that the backing valve is open; if not open it (press button "AAN/OPEN" simultaneously with button "AK"; reset the pump unit and switch on the pump (press the button "TP-DP" simultaneously with the button "AAN/OPEN").
    • If the backing valve is open read the backing pressure of the Thermovac TVV mounted in CAB064; it will be larger than 1E-1 mbar; you have a serious leak, contact a specialist.

For the detection chamber there are two pumping units the status of them being displayed on Vacuum Control Panel 3 in CAB066 as pumping units PS3-1 and PS3-2. In principle one should be able to run with one pump only, but the normal condition is that both pumps are working properly. A failure may be caused by a too small waterflow (waterkoeling LED blinks), a too low temperature of the pump (190 degrees LED blinks) or a too high backing pressure (TVV LED blinks) or a failure of the gas-control system for the detectors.

  1. Water cooling failure.
    • If there is a general water cooling failure contact a specialist.
    • If it is one pump only clean the waterflow regulator, reset the pump unit and switch on the pump (press the button "TP-DP" simultaneously with the button "AAN/OPEN").
  2. Too low temperature:
    • Check that the pump is still running (Pump Control Panel in CAB066), contact a specialist.
  3. Too high backing pressure:
    • Check that the backing valve is open; if not open it (press button "AAN/OPEN" simultaneously with button "AK"; reset the pump unit and switch on the pump (press the button "TP-DP" simultaneously with the button "AAN/OPEN").
    • If the backing valve is open read the backing pressure of the Thermovac TVV mounted in CAB066; it will be larger than 1E-1 mbar; consult a specialist because you have a serious leak.
  4. Gas-control failure for detection systems:
    • Consult a specialist.

Beam but no events in your detector system

1.Check your detector.

2. Check there is a target at the height of the beam; to be really sure use the telescope at the back of the magnet vacuum chamber.

3. Check that valves SK1 and SK2 are open. In case of doubt, make a visual inspection using the viewing glasses in the magnet chambers. E.g. it has happened that SK2 was partly closed without notification.

4. Check that the slits are not closed completely or that the diaphragm wheel is not at a proper position; to be really sure use the telescope at the back of the magnet vacuum chamber.

5. Check that tip field reading of the magnets corresponds with the calculated value of the code SETBBS.

Switching off the BBS

1. In the control room do the following.
  • Switch off TV monitors, oscilloscopes and Digital Volt Meters.

  • Set switch Ortec model 439 Digital Current Integrator to STANDBY.

  • Collect your items and make the electronics room and the DAQ room tidy.

  • Switch off the power supplies for Q1, Q2 and D using the VISTA control; first set current DAC's of Q1, Q2 and D1 to 0.0 A and when they reached their final value switch them off by clicking the "ON" button.

  • Ask operator to insert HEB beam stops (X-line and injection).

  • Ask operator to close section valve SKS2 in the Sb beamline window; this is entrance valve to scattering chamber.

2. In the experimental area do the following.

  • Measure radiation level and mark hot spots.
  • Close the valves SK1 and SK2 of the spectrometer.
  • Switch off gas control systems.
  • Switch off control for the rotation of the support and remove the key at the OFF position.
  • Store all tools in the toolbox cabinet and lock it.
Laatst gewijzigd:28 januari 2014 12:04