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Agenda

Agenda. A. Caldwell overview 15' S. Belogurov Shielding against cosmogenic activation: current results and prospects 15' V. Kornoukhov Enrichment & purification 45' S. Nisi ICPMS test at LNGS on natGe samples 20'

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Agenda

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  1. Agenda A. Caldwell overview 15' S. Belogurov Shielding against cosmogenic activation: current results and prospects 15' V. Kornoukhov Enrichment & purification 45' S. Nisi ICPMS test at LNGS on natGe samples 20' I. Abt status new detector design & prototypes 15' Joint meeting with TG10: K. Kroeninger simulation studies X. Liu test stands at MPI

  2. Delivery of 15 kg (nat)Ge from Krasnoyarsk Munich Special container to shield Ge from n,p 20 day trip. Very smooth no problems encountered

  3. Shielding container restacked, returned to Siberia for transport of enriched 76Ge. Shielding calculations will be discussed by S. Belogurov. Samples delivered to LNGS for ICP-MS measurements. Presentation by S. Nisi

  4. Simulation geometry Container: R1=70 cm, H1=126.5 cm Bottom depth 15 cm Cavity: R2=27 cm, H2=40 cm Ge-shipment: R3=21 cm, H3=27 cm OUT (8) Air (7) Container Fe (1) Cavity (2) Ge (3) Normalizing sphere (4), R=150 cm Air gap (6) 120 cm Ground (5) Depth= 4m Ground (5), Depth=4 m

  5. Attenuation factors For 68Ge production by N-component 10 For 60Co production by N-component 15-20 Taking into account contribution from m For 68Ge 8 For 60Co 12-15

  6. ICP-MS in the clean room at LNGS

  7. Ge93 13196contamination results

  8. The 15 kg nat Ge is currently in storage at the TU Muenchen. We will transport it to the HADES facility in the near future. Currently consider transporting and storing the enriched material to the HADES facility also. We need to organize the results from the different quality tests & set up database for tracking detector information.

  9. Procurement of 30 kg 76Ge: • 22 kg enriched by ECP/Svetlana • the material is enriched in GeF4 form, then converted to GeO2 at ECP. It seems that reduction in purity happens in this series of steps (see talk by V. Kornoukhov) • GeO2 must then be transformed to Ge, purified. We currently anticipate that this will be done at the Germanyi plant. GeO2 GeCl4  Chemistry  GeO2 (6N)  Ge • Measurements of GeO2 from ECP as good as 4N. Experiment performed to see if can skip GeCl4 step+ chemistry and increase yield beyond 72 %. Report by V. Kornoukhov • We need to decide how to proceed on purification. Proposal to perform new experiment with 30 kg natGe to measure yield from standard process using material from ECP.

  10. General idea of experiment: 4N  Is it enough?(Munchen, April 2005) At Svetlana: Ge metal 6N  GeF4  ! ! no centrifugation ! !  GeF4  GeO2  At FSUE Germaniy: GeO2  Ge Reduction&directional crystallization  Ge  Ge 6N poly zone refinement (if necessary)

  11. Conclusion from FSUE Germaniy (2) • Yield ofGe metal with > 47 Ohm*cm is 58% reached only after poly zone refinement of regulus. • Purity of this metal and standard GPZ is the same at DL of ICP MS measurements (we are still waiting for results of SS MS measurement), but concentration of majority carriers is 2*1013 cm-3. • GeO2 produced according to the ECP technology is not suitable for production of GPZ/HP germanium in direct technology “GeO2 reduction&directional crystallization Ge regulus” because of: • low resistivity of regulus ( < 5 Ohm*cm along a whole ingot (for standard regulus  > 30 Ohm*cm for L > 70% of total length); • High concentration of majority charge carriers n = 2*1013 cm-3 (for standard regulus n = 1.5*1012 cm-3). • They propose to carry out “full” cycle of 76GeO2 reprocessing, chemistry including. They can tune their equipment and complete “42 kg” experiment during 24 days (12 days for preparation and 12 days for experiment, sampling and certification including).

  12. New scheme of GeO2 purification:expected results (one of the versions) 30 kg • Duration ~ 9 days • total waste – 27.4% - 8.22 kg • recoverable waste – 22% - 6.6 kg in form of metal~ 2.4 kg in form of GeCl4 ~ 5 L~ 2.95 kg in form of solution ~ 800 L (~ 2.3 g/L) ~ 1.3 (1.8) kg • unrecoverable waste – 5.4% - 1.62 kg 21.78 kg

  13. Crystal Production: • So far, we have assumed that crystal production would take place at Umicore. Initial discussions, visit in December 2004 were very positive. At that time, Umicore promised to make a proposal to us how to proceed by mid-January 2005. • scheme for crystal growing received in mid-April after repeated gaps in communication • there will be significant material losses (scraps from cutting, samples for testing, grinding losses). Still need to understand how much can be recovered • the material will stay above ground for significant time. First crystal - 12.7 days, second 26 days, third 41 days … • at this time, we do not have an alternative to Umicore. Initial investigations found no firms in Russia. In U.S., Ortec & Canberra/Tennelec/Oak Ridge in principle options

  14. Detector production/simulations: • We have performed detailed MC studies of background rejection in segmented detectors. Talk by K. Kroeninger in MC session. • 5 test detectors have been ordered, 2 with the expected 18-fold segmentation. Detailed discussions with Canberra/Eurysis on contacts, supports, … To date, 2 detectors delivered, third is ready. Talk by I. Abt. • Test facilities set up at the MPI for the different types of detectors (p-type, n-type). Calibration sources in hand, first tests underway … Talk by X. Liu in MC session.

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

  16. 1st Test-stand: Eurysis Test-stand • Made in Eurisys • For Canberra crystals only • Dewar ~50cm H, ~20cm R • Heater at top and bottom (to evaporate LN2) • Plug & play Open for crystal heater Safety valve source Gas & LN2 Canberra-I Eurysis Gerda Collab. , Jun 27-29, 2005 Page 6

  17. MPI Test-stand Operation Critical: no condensation on crystal during warm-up  minimize time to remove LN2 and warm up detector.  Plan to use little heater. Expect the first result within 1-2 weeks. Load crystal During operation Gerda Collab. , Jun 27-29, 2005 Page 12

  18. Vacuum Test-stand • 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 Gerda Collab. , Jun 27-29, 2005 Page 15

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