construction and simulation of a compton scattering...

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:


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


Measurement Setup

fz

6M. ScheibelhutDPG, 24. March 2014

Characterization of the Germanium-Detector

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


Ener

gy /

keV

8M. Scheibelhut

Energy Calibration

Channel

133Ba

DPG, 24. March 2014


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

10M. Scheibelhut

Energy Resolution

DPG, 24. March 2014


11M. Scheibelhut

Energy / keV

60Co

DPG, 24. March 2014


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

Simulations of the whole Setup

12

Simulations


Geant4-Simulation

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


Any Questions?

Thanks to the Mainz XENON Group

16M. ScheibelhutDPG, 24. March 2014

Back up Slides


Backup Slides

17

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

19M. Scheibelhut

Rat

e /

1/s

Energy / keV

Peak Identification of the

Background


Backup Slides

construction and simulation of a compton scattering...

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