Post on 17-Mar-2019
Construction and Simulation of a
Compton Scattering Experiment with
a Xenon and a Germanium Detector
Melanie Scheibelhut
DPG, 24. March 2014 M. Scheibelhut
Institute of PhysicsExperimental Particle and Astroparticle Physics (ETAP)
Johannes-Gutenberg Universität Mainz
DPG Frühjahrstagung24. March 2014
Motivation of the Experiment in
Mainz
2
MainzTPC
M. ScheibelhutDPG, 24. March 2014
Ref: Phys.Rev D 88, 012006 (2013)Ref: Phys. Rev. C84, 045805 (2011)
Get more information about Xenon as detector mediumElectron recoils (Compton scatter experiment)Nuclear recoils (Neutron scatter experiment)
Study S1-pulseshapeDiscrimination of scintillation and ionization yield (low energy)
m
Nuclear Recoils
Principle of the MainzTPC
z-positionelectron drift time
x/y-positionposition of S2
3M. Scheibelhut
Drift Time
MainzTPC
Ref: Bastian Beskers
DPG, 24. March 2014
top PMT
bottom PMT
Compton Scatter Experiment
4M. Scheibelhut
Source
Scattering Target
= MainzTPC
xz
y
GermaniumDetector
γ
γ‘
'
cos112
0
'
h
cm
h
hEEE Ge
Energy of the scattered photon:
Compton Scatter Experiment
DPG, 24. March 2014
Angle Ring
Measurements with the Germanium
detector
5M. Scheibelhut
Ge-Detector
Collimatorwith Holder
Collimator Table
Cryostat with
MainzTPCShielding
Pipe
Ge-Detector Table
Rolling Plate of the Ge-Detector
Rolling Plate of the
Collimator
DPG, 24. March 2014
Compton Scatter Experiment
Characterization of the Germanium
detector
Energy calibration
Calibration sources
Energy resolution
Calibration sources
Different test pulses
Background measurement
7M. Scheibelhut
Isotop Energy /keV
214Am 59,54
133Ba 80,90
276,39
302,85
356,00
383,80
137Cs 661,66
60Co 1173,23
1332,49
Ref: http://www.nndc.bnl.gov/
DPG, 24. March 2014
Characterization of the Germanium-Detector
Ener
gy /
keV
8M. Scheibelhut
Energy Calibration
Channel
133Ba
DPG, 24. March 2014
Characterization of the Germanium-Detector
Gain 50
241Am
137Cs
60Co
9M. Scheibelhut
Energy Resolution
FWHM: 1. Statistical fluctuation in the
number of charge carriers:
2. Incomplete charge collection:
3. Electric noise:
Energy resolution:
Fanofactor:
Electron-Hole-Pair production energy:
2222
EXDT WWWW
EFWD 22 )35.2(2
XW2
EW
22222 )35.2( EmeasuredXmeasuredGeGeT WEWEFWE
008.0132.0 GeF
eV9.2Ge
Ref: Knoll, Radiation Detection and Measurement
Characterization of the Germanium detector
DPG, 24. March 2014
11M. Scheibelhut
Energy / keV
60Co
DPG, 24. March 2014
Characterization of the Germanium-Detector
Background without Shield- Background with Shield
= Background ReductionR
ate
/ 1
/s Without shielding
With shielding
Background Measurements
Energy / keV
Shielding Pipe
Ge
Rat
e /
1/s
Signals
Signal: events that have hits in both detectors. At least one in
the Ge-detector and one hit in the LXe after summing up
hits within a radius of 3mm and a height of 1mm.
Background: all other events that have hits in both detectors.
13
Simulations
M. Scheibelhut 13M. Scheibelhut
137Cs for 3.92° (Energy Range: 600-662keV)
Rat
e /
1/s
Rat
e /
1/s
Energy / keV Energy / keV
137Cs for 30.40° (Energy Range: 450-662keV)
Signal
Background
Signal
Background
DPG, 24. March 2014
Simulated Spectra in Ge Detector
30.4°
14
Simulations
M. Scheibelhut
Spatial Distribution
Coincident eventsFirst signal events in LXe
Cuts through the LXe-Volume
5mm highAround the middle
137Cs source is located at the left sideGe-Detector at 30.4° to the MainzTPC
Ge
DPG, 24. March 2014
Summary and Outlook
Development and construction of the geometry for the Compton scatter experiment
Characterization of the Ge-detector
Implementation of the setup into the simulations detailed simulations
Commissioning and measurements with the Compton scatter experiment
15
Summary
M. ScheibelhutDPG, 24. March 2014
Geometry of the Compton Scatter
Experiment
18M. Scheibelhut
Angle Ring 12x Threaded Bars
Cryostat with TPCShielding Pipe
Ge-Detector
Ge-Detector Table
Collimator with Holder
Collimator Table
Rolling Plate of the Collimator and the Cryostat Rolling Plate of the
Ge-Detector
DPG, 24. March 2014
Backup Slides