Monte-Carlo simulation of noise in hard X-ray Transmission Crystal Spectrometers: identification of contributors to the background noise and shielding optimization

I Thfoin; C Reverdin; S Hulin; C I Szabo; S Bastiani-Ceccotti; D Batani; E Brambrink; M Koenig; A Duval; X Leboeuf; L Lecherbourg; B Rossé; A Morace; J J Santos; X Vaisseau; C Fourment; L Giuffrida; M Nakatsutsumi

doi:10.1063/1.4890534

Monte-Carlo simulation of noise in hard X-ray Transmission Crystal Spectrometers: identification of contributors to the background noise and shielding optimization

Rev Sci Instrum. 2014 Nov;85(11):11D615. doi: 10.1063/1.4890534.

Authors

I Thfoin¹, C Reverdin², S Hulin³, C I Szabo⁴, S Bastiani-Ceccotti⁵, D Batani³, E Brambrink⁵, M Koenig⁵, A Duval², X Leboeuf², L Lecherbourg², B Rossé², A Morace⁶, J J Santos³, X Vaisseau³, C Fourment³, L Giuffrida³, M Nakatsutsumi⁵

Affiliations

¹ CEA, DAM, DIF, F-91297 Arpajon, France.
² CEA, Centre de Saclay, IRFU, F-91191 Gif-sur-Yvette, France.
³ CELIA, Université de Bordeaux-CNRS-CEA, F-33405 Talence, France.
⁴ Laboratoire Kastler Brossel, ENS, CNRS, UPMC, 75005 Paris Cedex, France.
⁵ LULI Ecole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau, France.
⁶ University of Milano, via Celoria 16, 20133 Milano, Italy.

PMID: 25430191
DOI: 10.1063/1.4890534

Abstract

Transmission crystal spectrometers (TCS) are used on many laser facilities to record hard X-ray spectra. During experiments, signal recorded on imaging plates is often degraded by a background noise. Monte-Carlo simulations made with the code GEANT4 show that this background noise is mainly generated by diffusion of MeV electrons and very hard X-rays. An experiment, carried out at LULI2000, confirmed that the use of magnets in front of the diagnostic, that bent the electron trajectories, reduces significantly this background. The new spectrometer SPECTIX (Spectromètre PETAL à Cristal en TransmIssion X), built for the LMJ/PETAL facility, will include this optimized shielding.