dvcs – hall a study of the background noise hugs 2008 florian itard
TRANSCRIPT
DVCS – Hall ADVCS – Hall A
Study of the Study of the Background NoiseBackground Noise
HUGS 2008
Florian ITARD
University Blaise University Blaise PascalPascal
Clermont-FerrandClermont-Ferrand
Laboratory of Corpuscular Physics (LPC)
Deeply Virtual Compton ScatteringThe simplest experiment to access to the GPDs
Small cross section ~ 10-9 Barn
Latest experiment ran in 2004Next experiment will run in may 2009
Exclusive experiment
Spectrometer
Up beam tube pipeDown beam tube pipe
Scattering chamber
Proton array
Calorimeter
Target
High luminosity ~ 2.5*1037 cm2.s
Important background noiseProduction of a continuous signal in the photo-mutipliers which is going to inconvenience the measure
Appeareance of a darkening in the cristal
Systematic errors
New calibration
yelded light undervalued
Curing?
Simulation Monte Carlo: GEANT 4
One aim: Reduce the background noise without change the place of the calorimeter in the last experiment
New detector simulation toolkit written in C++ and developped by The CERN collaboration
Enable to generate any particules and follow them in the geometry of the experiment
10 Millions electrons generated by run
9 hours calculation in a farm
Window of 640 ns
Reference results
Mean energy deposited by each electron reaching the target (KeV)
Cone beam pipe
Rectangular beam pipe
Tungsten shielding
Polyethylen front shielding
Final resultsMean energy deposited by each electron reaching the target (KeV)
Mean energy fonction on the depth of the block
Curing ?
THE END