Ge Test-stands at MPI Munich Xiang Liu 1.General 2.Crystals, Test-stands & Results 3.Outlook.

Ge Test-standsat MPI Munich

Xiang Liu

1. General 2. Crystals, Test-stands & Results3. Outlook

Crystals & Test-stands

Gerda Collab. , Jun 27-29, 2005

2 Canberra crystals (for test-stands II & III)Canberra-I : non-true coaxial, no segment (ready & tested)Canberra-II: coaxial, 18 segments, 6 x 3z

3 DSG crystals (for test-stands I & III)DSG-I : true coaxial, no segment (ready)DSG-II : 6 segments (ready)DSG-III: 18 segments, 6 x 3z

3 test-stands:Eurysis test-stand: for Canberra-I & II in LN2 (ready)MPI test-stand: for DSG I II & III in LN2 (almost ready)Vacuum test-stand: for DSG & Canberra crystals (September)

Goal


With Eurysis & DSG LN2 Test-stands:handling Ge in LN2Ge Properties (resolution etc. with source)Segmentations (coincidence cut for )Pulse shapes (true & non-true coaxial)MC verification (energy, pulse shape)

With Vacuum Test-stand:Dead layer thickness (with laser) source

Crystals Canberra-I


Canberra-I: non-true coaxial, no segment, mounted on stick

Canberra-II: 6 x 3z

preampcrystal

Crystals Canberra-I



Canberra-I Eurysis

Made in EurisysFor Canberra crystals onlyDewar ~50cm H, ~20cm RHeater at top and bottom (to evaporate LN2)Plug & play

heater

source

Gas & LN2

Open for crystal

Safety valve

1st Test-stand: Eurysis Test-stand

Eurysis Test-stand operation


Canberra-I Eurysis

Steps:1) Fill Dewer with LN2.2) Take Canberra-I out from vacuum can.3) Dip Canberra-I into LN2.4) Apply HV and measure.

Steps after measurement:1) Seal dewer gastight.2) Pump in gas N2 and LN2 out.3) Turn on top & bottom heater.4) Turn on heater around crystal for 2 hours.5) Take out canberra-I and put back to can

and make vacuum.

No condensation on crystal during warmup.

Results from Eurysis Test-stand


Jun 7th, 2005, Eurysis Test-stand with Canberra-I crystal.

FWHM ~5keV at 1.173MeV, need more investigation.

Crystal DSG-I


3 Ge crystals from DSG:DSG-I : P-type, true-coaxial, no segment.

Crystals DSG-II & III


DSG-II : P-type, true-coaxial, 6 phi segments (test at DSG done, now at Munich)

DSG-III: 6phi x 3z

2nd Test-stand: MPI Test-stand


Similar to Eurysis, made in MPIBigger dewer ~1m H, 30cm RGallow loading crystals.Only for DSG I, II & IIISimilar operating procedure.

Dewer

Hanging strings

Faraday cage

Cover

Crystal model

MPI Test-stand Operation


Expect the first result within 1-2 weeks.

Load crystal During operation

Critical: no condensation on crystal during warm-up minimize time to remove LN2 and warm up detector. Plan to use little heater.

MPI vs. Eurysis Teststand


In principle, can dip Canberra crystal into MPI test-stand, & v.v.Same physics tests

MPI test-stand has many advantages: closer to Gerda design (mini-Gerda), can test support strings & cable in LN2.built in house, easy to modify according to new requirement.Support strings flexible, can hang 2 crystals together and take coincidence data.Test-stand built in house, cost “no” money.

vs.

3rd Test-stand: Vacuum Test-stand


Vacuum tanks

Vacuum Test-stand


3 stations mounted togetherSources move in 3D around crystalCrystal fixed & cooled through LN2 pipesFor both Canberra & DSG crystals, sources & laser can be usedExpect first run September

DAQ


XIA Pixie-4.On board PC.Each card reads 4 channels.14bit ADC, 75MHz spc.for pulse shape.

PC Pixie card NIM cards for HV and preamp. power supply

Outlook


Eurisys Test-stand:More study with Canberra-I, solve resolution problem.Canberra-II detector end of this year

MPI Test-stand:DSG-I 1-2 week. True coaxial, good for pulse shapes.DSG-II crystal ready, 1-2 week, study segments and more pulse shapes.DSG-III arrive end of this year

Vacuum Test-stand:Start data taking SeptemberStudy dead layer with laser, hadronic interaction with sources.

Conclusion


Many test stand setups:Different crystals, non-true, true-coaxial, none, 6 & 18 segments.Different environment, LN2, Vacuum.Different sources, , & laser

Rich physics will be explored: Ge general properties.EM & hadron interactions.Pulse shape.All with MC simulations.

Any suggestions, ideas about measurement, simulation, please contact us!

Ge Test-stands at MPI Munich Xiang Liu 1.General 2.Crystals, Test-stands & Results 3.Outlook.

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