A Review of the Ge collaboration between USC and PNNL

1. A Review of the Ge collaboration between USC and PNNL Harry Miley Pacific Northwest National Laboratory

2. Outline • Pre-history: before we were fab • The race for 2 nu DBD T1/2: materials, depth, materials, mass, materials, isotopes… • The TWINS • SovDetOps • Enriched material: IGEX • All things shiny and distracting • Conclusions

3. Hanford Works environmental surveillance Early high-sensitivity radiation detection using NaI underground Methodical bkg reduction & sensitivity increase for environmental samples Before we were fab (i)

4. Pure science apps The atmosphere The oceans Cross sections Meteorites Lunar studies Astronaut studies Before we were fab (ii)

5. Approach: Fiorini’s Internal Source Method in 76Ge Plan: Rebuild existing low background germanium detector THEN: make a multi-crystal cryostat for a large mass experiment MAYBE: Get enriched isotopes one day Collaboration Starting Point

6. Diode-M Good materials, Arkie shield 1983: Homestake Pb, Fe, Cu shield Old Pb bricks = 1 PhD Indium contact replaced with Pb Single bead of solder: Po-210 The Race for 2n DBD T½ • Diode-M • Good materials, Arkie shield • 1983: Homestake • Pb, Fe, Cu shield • Old Pb bricks = 1 PhD • Indium contact replaced with Pb • Single bead of solder: Po-210

7. Superdetector M02287, still on the books 14 crystals in 2 cryostats Collaboration with PGT After many minor issues, passed all tests Never populated with crystals, but… Early thermal validation of our Majorana Ref Design The Road Not Taken

8. The bump that wasn’t Alpha background linear from 5 MeV to 2615 keV We just needed bkg to be linear for one more MeV. Guess what. It wasn’t. Detour: The Majoron “High Energy guys need an accelerator to create particles. You only need a computer.” -- Krish Gounder “Some you win, some you lose, some get rained out.” – Frank Avignone

9. Casual conversation in 1986: 68Ge/60Co limits sensitivity Could you rapidly deep mine Ge and make detectors? Yes, if you buy all the sugar in St. George UT & Quapaw, OK Result: Best low bkg detectors yet built Two 1.05 kg Ge xtals Elow << 10 keV Measured: ~ 8 atoms per cc 68Ge (somewhat suppressed) Also <9 mBq/kg 232Th in Cu TWINS: A scientist’s dream Shielding: 450 yo Pb 2000 yo Pb Eformed Cu

10. Some Comparisons

11. TWINS operated remotely at >50% duty cycle for two years. Thompson Aalseth Simplistic T1/2 Minimal manipulation Internal ‘debate’ > 1 yr Finally, some pay dirt! PRL 65 No 25 (1990) Miley et al How can you be sure this is double-beta decay and not yet another background?

12. Challenge: Move a GeLi from Baksan to Homestake Repackage in a TWIN cryostat Don’t kill it Don’t shut Homestake Achieve PNNL-USC background levels on the first shot Result: Confirmation of observation of two neutrino double-beta decay SovDetOps PLB 256 No. 3, 4 (1991) Avignone et al Only thing in common is count rate divided by number of 76 atoms! T1/2 in agreement with natural

13. As many know, enriching from 7% to 86% gives a large kick in sensitivity with no increase in BKG Need a Russian enrichment facility! Need an international collaboration! What few know is how addictive it is White powder ~$50/gram Enriched 76Ge: An Addiction

14. May, 1970 www.cia.gov Glasnost and Perestroika strike…. Formerly known as K-45, also known as Svetlana Plant Large facility that provides ~30% of Russia’s LEU Features department of Super- Clean Materials Centrifugation in Russia Frank Avignone • Electrochemical Combine Plant (ECP of Zelenogorsk) has supplied all the IGEX and HM 76Ge http://www.nti.org/db/nisprofs/russia/fissmat/enrichme/ekhz.htm http://www.ecp.ru/en/index.shtml

15. Location: Spain, Canfranc tunnel Assembly: Tennelec plus our best materials Rico Rico Grande 1, 2, 3 Background lessons Spanish lessons German lessons IGEX: International Germanium EXperiment

16. All things shiny and distracting • Axions at ORNL • Plus the Princeton gang (Calaprice to Kouzes) • Electron decay • Early WIMP limits • Spergel, Drukier • Dark Matter: Cosme • U Zaragoza: Angel and Julio Morales et al • 2n DBD of 100Mo • ITEP: Barabash et al • Axions at Sierra Grande… • Konstantin Zioutas, Rick Creswick, Smuel Nussinov , TANDAR, et al • Which became CAST

17. 1998 changed everything • Super-K result: Neutrinos have mass! • New era of low level measurements required

18. New approach: Find applications Get ACTUAL funding Hire experts Share funds with non-physicists like chemists, engineers, etc New Era of ULB Materials and Mechanical Engineering

19. Our group has grown 35 -> 120 WAS: Nuclear Chemistry IS: Radiation Detection and Nuclear Science HAD: 1 rad chemist (78) HAS: 5 rad chemists <29> JLAB, FermiLab physicsts As many of Frank’s students as possible And we are getting our own shallow underground lab Brodzinski Underground Lab Our interests are broad Remote detection Improved portals Automated systems Flight systems Non-proliferation R&D Explosion monitoring Global networks Active interrogation Separations chemistry US Domestic responses New fuel cycles Mass spec (many) Where are we, and which way are we pointing? Zero Neutrino DBD Dark Matter Coherent n scattering

20. A 28 year collaboration Mostly Frank and Ron Reduced backgrounds by more than a millionfold Started new efforts at PNNL Roll-your-own cryostat Electroplating Pulse processing Launched several (formerly) young people Miley, Guerard, Collar, Aalseth, Hossbach, others Smart, Thompson, etc Drove theorists crazy making revised double-beta decay T1/2 calculations Outlasted many other Ge DBD groups (not HM, tho) Established 329 building as “don’t show to DOE” zone Only ~$1M in DOE/HEP funds + ?? NSF with only 2n DBD and tight limits on 0n DBD to show for it Established a chance for US leadership in a world 1 ton 76Ge experiment Summary

21. Questions? Only known picture of them working. BTW, that’s Frank. They forgot the reflector underneath.