Integrated Large Infrastructures for Astroparticle Science N4 - Double beta Network Dominique Lalanne, Paris, November 19th 2007

Month number 48 corresponds to April 2008 9.N4 - Table 2 – DBD - Fourth 18 months Implementation Plan Tasks and Deliverables 37 th to 42nd month 43rd to 48th month 49th to 54th month WP 1: COORDINATION OF DBD SEARCHES Tasks: 1.4 - Common working group with JRA2 on the R&D projects in relation with the NA recommendations and follow-up of those R&D 1.5 - Common working group with the other 2 work packages Deliverables: - First version on report on interplay between N4 recommendation and JRA2 - White book on DBD common to all work packages (first version Month number 48 corresponds to April 2008

WP 2: BANK OF PURE ISOTOPES Tasks: 2.2 - Comparison of radiopurity results obtained by different methods and / or indifferent labs. 2.3C - Follow-up of ICR technique - Follow-up of LIS technique Deliverables: - Final report on radiopurity issues - White book on DBD common to all work packages (first version) WP 3: COLLECTION AND INVESTIGATION OF EXPERIMENTAL INPUTS, NUCLEAR MATRIX ELEMENTS - Common working group with JRA2 on R&D projects in relation with N4 recommendation and follow-up of those R&D - Pre-report on interplay between N4 recommendations and JRA2

Preparation for the N4 deliverables Co-ordinator Christine Marquet, CENBG, France In March 2008, deliverable for N4 network activities (It must prepare the final 5 years N4 deliverable for march 2009) Reports on N4: WG1 : Co-ordination of double beta decay searches co-ordinator: Xavier Sarazin, LAL-Orsay, France WG2 : Bank of pure isotopes. co-ordinator: E. Previtali, INFN Milano, Italy WG3 : Theoretical developments co-ordinator: J. Suhonen, Jyväskylä University, Finland For WG1: we propose that this report will be very similar to the ASPERA roadmap + details of the R&D Status of the differents projects Each project (GERDA, CUORE, and GERDA) has to give an updated status before 30 January 2008 (3 to 5 pages should be OK)

Main issues and recommendations The European next-stage detectors are GERDA, CUORE and Super-NEMO. Cobra is in R&D stage but might be a promising technique. The three experiments with germanium, bolometers and tracko-calo detectors have skill and experience ready for the next generation of double beta experiments. These techniques have recent improvements showing capabilities and reliability for possible low level of background which is the main issue for the expected sensitivity on the neutrino mass. These three experiments could operate their full detector in 2010-2012 with a final sensitivity on the effective neutrino mass mbb around 50 meV. With their sensitivities and complementary experimental approaches the three experiments could prove or disprove the KKGH claim. Their motivation: exploration of the parameter range predicted by the inverted mass hierarchy. Our recommendation is to keep these three axes of study in the double beta research field. With these detectors, Europe will be in the best position to improve sensitivity, maintain its leadership in this field, to prove or discard “degenerate” neutrino mass scenarios, … … and may be able to finally discover the Majorana nature of neutrino.

WP1, deliverables : - First version on report on interplay between N4 recommendation and JRA2 - White book on DBD common to all work packages (first version) Most of the work has been done for ASPERA

WP2, deliverables : Final report on radiopurity issues - White book on DBD common to all work packages (first version) Work almost done in previous reports - Updating of the data base of double beta emitters To be added 38 kg of enriched Ge76 1.5 kg of enriched Se82

Pre-report on interplay between N4 recommendations and JRA2 WP3 deliverables : Pre-report on interplay between N4 recommendations and JRA2 - White book on DBD common to all work packages (first version) Recommendations correspond to a confidence on matrix elements of double beta emitters Work on good tracks

ILIAS-JRA2 Integrated Large Infrastructures for Astroparticle Science Enrichment and purification of Se82 recent delivery : 1.5 kilos of enriched Se82 from Tomsk

1.5 kg from Tomsk

New deliverables : purified Selenium by chemistry INL (Idaho) 1 kg of Se82 done by distillation Kurchatov 1 kg of Se (nat.) done IChHPS (Russia) 1.250 kg of Se (nat.) done Conclusion : a lot of measurements to be done on Germanium detectors in LSM

82Se Purification for SuperNEMO J. D. Baker Idaho National Laboratory C. A. McGrath Idaho National Laboratory C. S. Sutton Mount Holyoke College A. M. Caffrey Mount Holyoke College J. Horkley Idaho State University ISU, Pocatello, ID November 8, 2007

Se Purification • Weigh Se • Add quartz distilled 6 M HNO3 to dissolve Se • Heat until dryness • Add nanopure H2O • Add quartz distilled 2 M HCl • Add barium solution (First time) • Add H2SO4, precipitate carries Ra • Filter Solution (first time)

Se Purification continued Add barium solution (Second time) Filter Solution (second time), improves separation from Ra Add saturated Na2S2O5, reduces Se to metal which precipitates, SO2 would be better Let the solution stand Filter Se Combine filtrates and reduce volume, precipitate Se metal Rinse the Purified Se Add Se to quartz boats, place boats in furnace, dry Se under He purge. Weigh ultra-purified Se Add ultra-purified Se to clean shipping container

Natural Se Purification Results Sample (mBq/kg) Mass (g) Measurement time (h) 40K 60Co 137Cs 226Ra 228Ra 228Th Ru natural Se 196 447.33 668 ± 31 < 1 2.1 ± 0.9 46 ± 2 13 ± 2 11 ± 2 485 Purified natural Se 563 436.56 < 20 < 0.7 1.0 ± 0.4 < 0.9 < 2.4 < 1.6 3 Reduction Factor < 33 --- < 51 < 5.4 < 6.9 162

Nd source production Enrichment : MENPHIS, still under discussion, but lasers will NOT be dismantled collaboration between SuperNEMO and SNO+, Nd150, November 7th, 2007 for enrichment and purification Source shaping for SuperNEMO : open question Chair person for source production (Se and Nd) : Corinne Augier

Purification of Nd liquid scintillator Xiongxin Dai Queen’s University SNO+ collaboration meeting, May 30th, 2007

Backgrounds for neutrinoless double beta decay 1yr, 1000kg natural, 150meV

A reduction of >106 is required!!! Radio-purification goals: 228Th and 228Ra in 10 tonnes of 10% Nd (in form of NdCl3 salt) down to <110-14 g 232Th/g Nd Raw NdCl3 salt measurement: 228Th equivalents to 32±2510-9 g 232Th/g Nd A reduction of >106 is required!!!

Requirements for Nd Radio-purification Techniques Very high efficiency for 228Th and 228Ra No significant Nd loss after purification No significant pH change No addition of other impurities, which can interfere with the Nd-LS synthesis Fast Low cost Safe

Extraction efficiency Spike test results: Extraction efficiencies of Th and Ra in 10% NdCl3 using HZrO and BaSO4 Purification method Adsorbent Conc Extraction efficiency 228Th 226Ra HZrO coated filter 10 g Zr/m2 53.1±2.4% <10% HZrO mixed-in 0.1 mg/g Zr 0.44 mg/g Zr 0.82 mg/g Zr <5% 99.06±0.22% 99.89±0.02% 30.7±5.7% 30.1±9.0% BaSO4 coated filter 10 g Ba/m2 BaSO4 mixed-in 1.0 mg/g Ba 9.5±4.7% 63.4±1.9% BaSO4 co-precipitation 0.49 mg/g Ba 1.39 mg/g Ba 20.4±4.4% 62.8±2.3% 97.2±0.2% 99.89±0.03%

Proposed purification methods for 10% NdCl3 aqueous solution Step 1 (BaSO4 co-precipitation for Ra): - add BaCl2 solution into 10% NdCl3, and mix well for 30min; - add (NH4)2SO4 solution, and Ra co-precipitates with BaSO4, mix for 30min; - let precipitate settle, and filter the purified NdCl3 supernatant solution Step 2 (HZrO mixed-in purification for Th): - Prepare HZrO absorbent: neutralize ZrCl4 with NH4OH, separate the precipitate and rinse with UPW; - add HZrO into 10% NdCl3, mix for 2 hours to extract Th onto HZrO;

Total NdCl3: 10 tonnes of 10% Nd solution Nd purification plant Total NdCl3: 10 tonnes of 10% Nd solution Purification goal: <110-14 g 232Th/g Nd Turn-around time: - 200L/batch, 2 batches/week → 25 weeks - Nd purification can be done in parallel with the Nd-LS production The design of the Nd purification plant has started at Queen’s

New chair persons for ILIAS N4 : chair Christine Marquet deputy Xavier Sarazin JRA2, enrichment and purification : chair Corinne Augier