Skip to ContentSkip to Navigation
KVI - Center for Advanced Radiation TechnologyOnderzoek en onderwijsAGORIrradiations of Materials

Control system and data acquisition

Irradiation runs are computer controlled. The fluence of the irradiation is set and started by the operator and the run is stopped by the control computer when the programmed fluence has been reached. The run can also be stopped manually on demand of the client at any time. If needed, the flux can be stored every 0.5 second by the data acquisition.

Range telescope
Range telescope.

Beam diagnostics

Energy Measurement

A range telescope (Multi-Leave Faraday Cup, MLFC) can be used to measure proton energies. The MLFC consists of a stack of 64 aluminum sheets that are interspersed with Kapton foils. The absolute accuracy of the energy measurement with the MLFC is approximately 1%, the relative accuracy is about 0.02%.

Field measured with Lanex screen/ CCD camera set up
Field measured with Lanex screen/ CCDcamera set up.
Field shape and homogeneity

Field shape and homogeneity of the irradiation field are assessed with a Lanex scintillating screen. The image of the screen is captured with a CCD camera and is used to visualize and quantify the homogeneity of the irradiation field.

Typical flux calibration starting from a 184 MeV p primary beam
Typical flux calibration starting from a 184 MeV p primary beam
Flux calibration

During the irradiation the flux is monitored with a Beam Intensity Monitor (BIM). This is an ionisation chamber positioned in the beam. The output current of the chamber is digitised into a pulse train, such that every pulse (monitor unit, MU) represents an amount of charge from the chamber.

Before an irradiation the BIM signal (in Monitor Units, MU) is related to the scintillator signal to obtain the flux calibration in protons per cm2 per MU. The proton flux at the centre of the irradiation field is measured using a Farmer chamber and/or with a 10 mm diameter scintillator detector.

Horizontal field scan at the DUT position for 184 MeV p and 80 mm field collimator
Horizontal field scan at the DUT position for 184 MeV p and 80 mm field collimator

This calibration is conducted for every field size and every energy used during an irradiation.

Simulation of the dose in Si fo a 1010 p cm-2 solar flar
Simulation of the dose in Si fo a 1010 p cm-2solar flar

Monte Carlo simulations

A Monte-Carlo model of the irradiation set-up has been developed. This model is such that all components can be shifted in 3 dimensions allowing easy rearrangement of the setup of the beam line to assess e.g. proton fluxes and energy distributions at the position of the DUT.The model has been validated by a series of measurements.

Comparison of measurements and Monte carlo simulations for the MLFC
Comparison of measurements and Monte carlo simulations for the MLFC
Last modified:04 January 2018 3.19 p.m.