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ILIAS-JRA2

I ntegrated L arge I nfrastructures for A stroparticle S cience. ILIAS-JRA2. Production of enriched Selenium 2 kilos « ITEP-Kurchatov » New contacts with ECP-Krasnoyarsk New production from Tomsk What’s next ?. Second kilogram of enriched Selenium “ITEP-Kurchatov”

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ILIAS-JRA2

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  1. Integrated Large Infrastructures for Astroparticle Science ILIAS-JRA2 • Production of enriched Selenium • 2 kilos « ITEP-Kurchatov » • New contacts with ECP-Krasnoyarsk • New production from Tomsk • What’s next ?

  2. Second kilogram of enriched Selenium “ITEP-Kurchatov” (A. Barabash, L. Sosnin and A. Cheltsov) 22 days of statistics First kilogram, reminder:

  3. Collaboration meeting, Prague, November 2004

  4. November 2004

  5. Conclusion on Kurchatov-ITEP production: 1- remaining pollution of radioelements : Ra226 gives the Bi214 contamination 3 mBq/kg in the second kilo, 100 times too high Ra228 and Th228 gives the Tl208 contamination so 3 mBq/kg is a factor of 1000 too high for a source of SuperNEMO Ru106 is a beta emitter of Q ~ 3 MeV so pollution is catastrophic ! (20 mBq/kg) 2- need of « new producers » : ECP-Krasnoyarsk contacts

  6. ECP-ILIAS meeting Orsay, March 9-10, 2006 Participants : Dmitry Kononov, Yuri Kulinich, Elena Nikitina, ECP-Krasnoyarsk Serge Jullian, Dominique Lalanne, Xavier Sarazin, LAL-Orsay Alexander Barabash, ITEP-Moscow Goal of the meeting  study of a possible production of enriched 82Se in the ECP-Krasnoyarsk facility in order to test the level of purity of the final product and comparison to the level needed for the next generation of Double Beta experiment.

  7. Yuri Kulinich presented the possibilities in ECP-Krasnoyarsk. For hundreds of kilograms it is without problems, the facility has the goal of mass production. For example it is ~ 30% of Russian enriched Uranium production and ECP is largest producer of stable isotopes in the world. There are different units and the one devoted to enriched Selenium will be a new one, never used before, so in principle with a low level of radio-impurities. This facility is closely connected to units for chemical purification and chemical treatment. Each new isotope needs special equipment and there is for each a special unit dedicated to.

  8. Dmitry Kononov is an expert in the chemical treatment of Selenium. For the current Selenium production the level of chemical impurities at the output of the facility are the following : Bismuth : 40. 10-11 g/g ( = 5000 mBq/kg if supposing chain at equilibrium) Thallium : 7. 10-11 g/g ( = 400 mBq/kg if supposing chain at equilibrium) So both at a level 100 times too high

  9. Tender in June 2006 for a production of 1.5 kilo of enriched Se82 SURPRISE : ECP-Krasnoyarsk… …and a second answer : Chemgas -Tomsk Choice done for Chemgas-Tomst (better price) According the procedure, not possible to make a different choice Need of a new order to ECP, but of lower amount of money and a new funding, ILIAS being not enough

  10. All possible sites in Russia are (and Chemgas is in touch with all of them) : For Se82, the choice of Chemgas is Tomsk Actually Alexander Barabash thinks that the 2 kilos tagged « ITEP-Kurchatov » were produced in Tomsk (September 2006 announcement !). At my last questioning in June 2006 at Santa Fe, Alexander confirmed me that the 2 physicists of Kurchatov were doing the job (but I have still no report on this from Kurchatov).

  11. ILIAS work summary In 2003, what we thought : 1- Selenium was not possible to buy, but as in NEMO 3 we have to rent it (possible for years…) 2- Kurchatov (via ITEP) was the only producer in our case So, we did a Convention with ITEP for a rent of 2 kilos In 2006 what we know : 1- after a meeting in Munich with the Gerda team : it is possible to buy Selenium as they do for Germanium 2- There is 3 possible plants in Russia, Krasnoyarsk (able to produce hundreds of kg), Tomsk (almost able of hundred), Kurchatov (for kilograms). 3- there is a French importer (Chemgas) in touch with these 3 centers, ready to organize meetings with the real producers.

  12. History of the first 2 kilograms of « Kurchatov » After the first kilogram production, the pollution of Ru should have been discussed for understanding the origin. We never had any information on this discussion, and the second kilo had the same pollution. Actually, what we discovered in november 2006 : 1- the 2 kilos were not produced in Kurchatov but in Tomsk 2- the information of Ru pollution was never sent to Tomsk

  13. ILIAS-JRA2 Purification of Selenium Chemical purification at INL results of sample of natural selenium purification of the first kilo of ITEP-Kurchatov Physical purification Kurchatov team IChHPS team

  14. John Baker new developments (updated September 2006) Next talk from John Baker Tests on natural Se before purification of the batch of enriched Se82 Purification for Ru : adding natural Ru to 485 ppb then purification and redissolution of Se level of Ru = 3ppb purification factor = 160 Test of losses of Se : none in dissolution of nitric acid, drying down and redissolution in HCl and barium sulfate precipitation Reduction of Se to metal : not 100% but can be worked around by concentration the Se in solution (similar to Mo). No problem Purification of the batch of enriched Se82 : October 2006 To be finished beginning of 2007

  15. Mikhail Churbanov, Institute of Chemistry of High Purity Substances/ Russian Academy of Sciences (IChHPS/RAS), Nishny Novgorod Next talk from Vasily Kornoukhov In the case of rectification the level that can be reached for Uranium traces is less than 9.10-14 g/g (corresponding to 1 mBq/kg if the chain is at equilibrium). This method seems to be appropriate to the requirements of the double beta source we have in project. Remind : the level to be reached for SuperNEMO is 10 mBq/kg for Bi214 and 2 mBq/kg for Tl208. Mikhail Churbanov, Director of IChHPS, presented the studies of the purification of Selenium and the installations existing at IChHPS. This Institute has been purifying Selenium since 20 years and has a deep knowledge of the physical and chemical processes involved in chemistry and distillation. Distillation has to deal with different compounds of Selenium as cycloSe8, katenopoly-Se and polycyclo-Se in chemical equilibrium. Melting and boiling points depend on the structure. With radium it has to be taken into account the existence of compound as RaSe. At IChHPS various techniques are used for distillation : one-stage distillation multistage distillation rectification (multistage in one run)

  16. ILIAS-JRA2 Measurements of residual radioactivity in selenium batch Matthias Laubenstein at Gran Sasso (Germanium crystal) Vasily Kornoukhov at INR (with proportionnal counters measuring radon emanation, but so, only for Bi214) Warsaw group : TPC imaging, possible for Radon (Rn222) and Thoron (Rn220)

  17. If it is possible to hope a level of 300 mBq/kg for Bi and Tl at the production level (as mentionned before) A factor of 50 on Ra226 fits the specification for Bi214 A factor of 10 (but may be it’s better, here only limits) for Ra228 is much too small for Tl208, we need a factor 100

  18. To prove the possibility of purification by a factor of 100 for Tl208 We must choose a new sample of natural Se with a greater level of Tl208 before purification, then purify it…then measure it.. … or measure the sample purified by John Baker, as we have only limits, by a more sensitive technique, but how ??? or…. wait for BiPo !

  19. Remark: This « best Germanium in the world » can reach a sensitivity of 1 mBq/kg when measuring 1 kg (with a greater statistics, that could be as low as 500 mBq/kg To reach the level of mBq/kg, we all know that the BiPo detector is needed but new developments are possible

  20. Proportional counters and radon degassing (old technique but with new inputs) (Vasily Kornoukhov, INR) Development scheduled in 2007 Next talk from Vasily Kornoukhov

  21. TPC with CCD camera Warsaw group Possibility of Radon 220 measurement in SuperNEMO gas Next talk from Zenon Janas

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