MICOSa CHERNE collaboration

in applied research involving industry

François Tondeur, Lara Marwaha, Isabelle Gerardy, Jonathan Baré

ISIB José Rodenas, Sergio Gallardo

UPV

MICOSminiaturisation of the Compton

spectrometer

• PRINCIPLE

Measurement on the scattered X-ray beam to avoid detector saturation

The Compton spectrometer in the 1990’s

• Matscheko et al RTI Electronics

A big, heavy device adapted to a Ge detector

The Compton spectrometerin CHERNE

• UP Valencia: Gallardo, Rodenas, Verdu Monte Carlo simulation of the Compton scattering technique applied to characterize diagnostic X-ray spectra

• U. Bologna: Fernandez, Scot, Baré et alReconstruction of the X-ray tube spectrum from a scattering measurement

• ISIB Bruxelles: Marwaha, Tondeur et alpresent work

MICOS

• Development of a small portable device for routine spectrometric controls of X-

ray generators• 4-year FIRST project supported by the

Walloon region 2008-2012• Industrial cooperation with Balteau

NDT and Canberra Benelux• Academic collaboration with UP

Valencia

MICOS partnership

• Project coordinated by ISIB, and executed at ISIB lab of nuclear and radiation physicsresearch fellow: Lara Marwaha (ex-FHA)

• UPV: training of the research fellow to MC simulation and to the « old » spectrometer

• Balteau: manufacturer of the shielding + sales in the industrial sector

• Canberra: provided detectors for the project + sales in the medical sector

MICOS main steps

• Design of a simplified shielding

• Tests of detectors and choice of a detector

• MC simulation and validation

• Choice of the methodology for unfolding

Shielding design• 3 options according

to energy : maximum 150, 300 or 450 keV

• Design with MC simulation

• Steel/lead/copper for 150 kV and 300 kV

• 450 kV: W cover above the 300 kV device

Choice of the detector

• Limited choice of « pen-type » detectors diam.<20 mm, reasonable cost

• Tested : CZT, CdTe, NaI• CZT- CdTe: not easy to simulate with MC

(problems with dead layers, variability from one detector to another, response depending on electronics settings…)

• Choice: NaI – easy to simulate with MC

Monte Carlo simulation• Geometrical model validated with

radioactive sources: 241Am, 109Cd, 57Co, 137Cs

thickness of front

window fitted to

experimental data

• Response matrix of 150 keV prototype calculated with 1 keV interval

Deconvolution• A specific algorithm similar to GRAVEL

gives good results in few iterationssensitive to good energy calibration

MICOS going on

• 300/450 keV prototype soon manufacturedsimulation-validation-unfolding-testing

• Back to CZT/CdTe improve the geometrical model and the

simulation of the response

• Students from CHERNE welcome for a master thesis

Thank you