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

2. Crystals & Test-stands Gerda Collab., Jun 27-29, 2005Page 2 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)

3. Goal Gerda Collab., Jun 27-29, 2005Page 3 With Eurysis & DSG LN2 Test-stands: handling Ge in LN2 Ge 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

4. Crystals Canberra-I Gerda Collab., Jun 27-29, 2005Page 4 Canberra-I: non-true coaxial, no segment, mounted on stick Canberra-II: 6  x 3z preamp crystal

5. Crystals Canberra-I Gerda Collab., Jun 27-29, 2005Page 5

6. Gerda Collab., Jun 27-29, 2005Page 6 Canberra-I Eurysis Made in Eurisys For Canberra crystals only Dewar ~50cm H, ~20cm R Heater at top and bottom (to evaporate LN2) Plug & play heater source Gas & LN2 Open for crystal Safety valve 1 st Test-stand: Eurysis Test-stand

7. Eurysis Test-stand operation Gerda Collab., Jun 27-29, 2005Page 7 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.

8. Results from Eurysis Test-stand Gerda Collab., Jun 27-29, 2005Page 8 Jun 7 th, 2005, Eurysis Test-stand with Canberra-I crystal. FWHM ~5keV at 1.173MeV, need more investigation.

9. Crystal DSG-I Gerda Collab., Jun 27-29, 2005Page 9 3 Ge crystals from DSG: DSG-I : P-type, true-coaxial, no segment.

10. Crystals DSG-II & III Gerda Collab., Jun 27-29, 2005Page 10 DSG-II : P-type, true-coaxial, 6 phi segments (test at DSG done, now at Munich) DSG-III: 6phi x 3z

11. 2 nd Test-stand: MPI Test-stand Gerda Collab., Jun 27-29, 2005Page 11 Similar to Eurysis, made in MPI Bigger dewer ~1m H, 30cm R Gallow loading crystals. Only for DSG I, II & III Similar operating procedure. Dewer Hanging strings Faraday cage Cover Crystal model

12. MPI Test-stand Operation Gerda Collab., Jun 27-29, 2005Page 12 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.

13. MPI vs. Eurysis Teststand Gerda Collab., Jun 27-29, 2005Page 13 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.

14. 3 rd Test-stand: Vacuum Test-stand Gerda Collab., Jun 27-29, 2005Page 14 Vacuum tanks

15. Vacuum Test-stand Gerda Collab., Jun 27-29, 2005Page 15 3 stations mounted together Sources move in 3D around crystal Crystal fixed & cooled through LN2 pipes For both Canberra & DSG crystals ,  sources & laser can be used Expect first run September

16. DAQ Gerda Collab., Jun 27-29, 2005Page 16 XIA Pixie-4. On board PC. Each card reads 4 channels. 14bit ADC, 75MHz spc. for pulse shape. PCPixie card NIM cards for HV and preamp. power supply

17. Outlook Gerda Collab., Jun 27-29, 2005Page 17 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 September Study dead layer with laser, hadronic interaction with sources.

18. Conclusion Gerda Collab., Jun 27-29, 2005Page 18 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!