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The M AJORANA Project

The M AJORANA Project. Science of  M AJORANA Demonstrator Detailed description Some technical issues Toward a 1-ton Experiment. What is  ?. Fig. from Deep Science. Fig. from arXiv:0708.1033.  and the neutrino.  (0  ) decay rate proportional to neutrino mass

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The M AJORANA Project

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  1. The MAJORANA Project Science of  MAJORANA Demonstrator Detailed description Some technical issues Toward a 1-ton Experiment

  2. What is ? Fig. from Deep Science Fig. from arXiv:0708.1033 Steve Elliott

  3. and the neutrino • (0) decay rate proportional to neutrino mass • Most sensitive technique (if Majorana particle) • Decay can only occur if Lepton number conservation is violated • Leptogenesis? • Decay can only occur if neutrinos are massive Majorana particles • Critical for understanding incorporation of mass into standard model • is only practical experimental technique to answer this question • Fundamental nuclear/particle physics process Steve Elliott

  4. bb Decay Rates G are calculable phase space factors. G0n ~ Q5 |M| are nuclear physics matrix elements. Hard to calculate. mn is where the interesting physics lies. Steve Elliott

  5. Elliott & Vogel Annu. Rev. Part. Sci. 2002 52:115 Past Results CURE Steve Elliott

  6. A Recent Claimhas become a litmus test for future efforts  is the search for a very rare peak on a continuum of background. ~70 kg-years of data 13 years The “feature” at 2039 keV is arguably present. NIM A522, 371 (2004) Steve Elliott

  7. Future Data Requirements Why wasn’t this claim sufficient to avoid controversy? • Low statistics of claimed signal - hard to repeat measurement • Background model uncertainty • Unidentified lines • Insufficient auxiliary handles Result needs confirmation or repudiation Steve Elliott

  8. KKDC Claim 50 meV Or ~ 1027 yr Atmospheric Scale Inverted Solar Scale Normal Steve Elliott

  9. An Ideal ExperimentMaximize Rate/Minimize Background Large Mass (~ 1 ton) Large Q value, fast bb(0n) Good source radiopurity Demonstrated technology Ease of operation Natural isotope Small volume, source = detector Good energy resolution Slow bb(2n) rate Identify daughter in real time Event reconstruction Nuclear theory Steve Elliott

  10. Background Considerations • (2) • natural occurring radioactive materials • neutrons • long-lived cosmogenics At atmospheric scale, expect a signal rate on the order of 1 count/tonne-year Steve Elliott

  11. The usual suspects • (2) • For the current generation of experiments, resolutions are sufficient to prevent tail from intruding on peak. Becomes a concern as we approach the ton scale • Resolution, however, is a very important issue for signal-to-noise • Natural Occurring Radioactive Materials • Solution mostly understood, but hard to implement • Great progress has been made understanding materials and the U/Th contamination, purification • Elaborate QA/QC requirements • Future purity levels greatly challenge assay capabilities • Some materials require levels of 1Bq/kg or less for ton scale expts. • Sensitivity improvements required for ICPMS, direct counting, NAA Steve Elliott

  12. As we approach 1 cnt/ton-year,a complicated mix emerges. • Long-lived cosmogenics • material and experimental design dependent • Minimize exposure on surface of problematic materials • Development of underground fabrication • Neutrons (elastic/inelastic reactions, short-lived isotopes) • (,n) up to 10 MeV can be shielded • High-energy- generated n are a more complicated problem • Depth and/or well understood anti-coincidence techniques • Rich spectrum and hence difficult at these low rates to discern actual process, e.g. (n,n’) reactions - which isotope/level • Simulation codes are imprecise wrt low-energy nuclear physics • Low energy nuclear physics is tedious to implement and verify Steve Elliott

  13. 1-ton Ge - Projected Sensitivity vs. Background Goal is to achieve ultra-low backgrounds of less than 1 count per ton of material per year in the ROI about the bb(0n) Q-value energy. Steve Elliott

  14. MAJORANA

  15. MAJORANACollaboration Goals Actively pursuing the development of R&D aimed at a ~1 tonne scale 76Ge 0-decay experiment. • Technical goal: Demonstrate background low enough to justify building a tonne scale Ge experiment. • Science goal: build a prototype module to test the recent claim of an observation of 0. This goal is a litmus test of any proposed technology. • Work cooperatively with GERDA Collaboration to prepare for a single international tonne-scale Ge experiment that combines the best technical features of MAJORANA and GERDA. • Pursue longer term R&D to minimize costs and optimize the schedule for a 1-tonne experiment. Support: As a R&D Project by DOE NP & NSF PNA Steve Elliott

  16. The MAJORANADEMONSTRATOR Module 76Ge offers an excellent combination of capabilities & sensitivities. (Excellent energy resolution, intrinsically clean detectors, commercial technologies, best 0sensitivity to date) • 60-kg of Ge detectors • 30-kg of 86% enriched 76Ge crystals required for science goal; 60-kg for background sensitivity • Examine detector technology options focus on point-contact detectors for DEMONSTRATOR • Low-background Cryostats & Shield • ultra-clean, electroformed Cu • naturally scalable • Compact low-background passive Cu and Pbshield with active muon veto • Agreement to locate at 4850’ level at Sanford Lab • Background Goal in the 0peak ROI(4 keV at 2039 keV) ~ 1 count/ROI/t-y (after analysis cuts) Steve Elliott

  17. MAJORANA DEMONSTRATOR Overview Steve Elliott

  18. MAJORANADEMONSTRATOR Module Sensitivity • Expected Sensitivity to 0(30 kg enriched material, running 3 years, or 0.09 t-y of 76Ge exposure) • T1/2 1026 y (90% CL).Sensitivity to <m> < 140 meV (90% CL) [Rod05,err.] Steve Elliott

  19. Cosmogenic 68Ge and 60Co 288d 68Ge 68Ga 68Zn 2.9 MeV 68Ge and 60Co are the dangerous internal backgrounds For 60-kg enriched detector, initially expect ~60 68Ge decays/day. t1\2 = 288 d Minimize exposure on surface during enrichment and fabrication PSD, segmentation, time correlation cuts are effective at reducing these Steve Elliott

  20. ~x10 Point Contact Detectors Hole vdrift (mm/ns) w/ paths, isochrones Steve Elliott Barbeau et al., JCAP 09 (2007) 009; Luke et al., IEEE trans. Nucl. Sci. 36 , 926(1989).

  21. Point Contact Detectors Realization that a design based on commercial “BEGe” detectors might be advantageous. Steve Elliott

  22. Front End Electronics Pulse Reset Resistive Feedback COGENT front ends (U Chicago) UW “Hybrid” Design LBNL Design Steve Elliott

  23. String Designs Steve Elliott

  24. 18 natural-Ge Canberra BEGe’s on order ∅ = 70±2.5 mm, h = 30±2.5 mm 579 g active mass contact r < 6.5 mm (5 mm nom.) Front surface metalized for HV 4 to 6 crystals per string Front-ends mounted next to the crystal Closed cold plate and beefier Cu in detector mounts for added strength First Module Steve Elliott 24

  25. Shield Design Side View Top View Steve Elliott

  26. Sanford Lab Layout - Draft Steve Elliott

  27. ECP Centrifuges NID Plasma Separator Acoustic Enrichment Demonstration Alternative Separation of 76Ge • Demonstrator needs roughly 50 kg of 76Ge • Russian centrifuge separation is the project baseline at ~$60/g • ECP of Zelenogorsk supplied all the isotope for IGEX and HM experiments • Evaluated possible alternative methods for separation: • thermal diffusion enrichment (SBIR developed - ready for test run) • acoustic enrichment (immature) • plasma enrichment (promising) • UCLA spinoff, Nonlinear Ion Dynamics (NID), developing plasma separation isotope business - NIH funded development of machine for 18O production • Majorana has contracted NID to produce a report and 76Ge material sample Steve Elliott

  28. Copper Production Plating to several cm without machining Presently plating 2-5 mil/day Developing configurations, waveforms, recipes to improve buildup rate Purity limitations vs. buildup rate will come from 228Th tracer studies. Copper Cleanliness Assay data indicates that CuSO4 in bath is source of Th in part Producing our own CuSO4 from pure starting materials has been more successful in producing clean Cu then re-crystalizing the CuSO4. Initial ICPMS study in 2005 5-10 mBq/kg, limitation in materials, prep Improved to 2-4 mBq/kg Goal <1 mBq/kg Electroforming and Cu Purity - Material purity Steve Elliott

  29. Underground electroforming at WIPP - Cu purity • Electroform a part underground • Electroformed Cu is extremely pure, very little Th/U. By electroforming UG, the cosmogenic isotope Co-60 should be eliminated also • Demonstrate that one can safely form a part underground in a highly regulated environment • WIPP follows a strict safety protocol directed by DOE and MSHA • Low voltage system to plate Cu from 1.2 M acid solution onto SS mandrel Test Part Copper “Beaker” fabricated 660 gm 160 mm high, 110 mm diameter Wall thickness ~1 mm ~10 days of UG electroforming in two stretches Solution is 1.5 kg copper sulfate dissolved in 16 L 1.2M sulfuric acid Part removed from mandrel by successive dunks in boiling water and liquid nitrogen Steve Elliott

  30. Low-background cryostat testing at WIPP - Large cryostats • Progress in the MEGA cryostat • Installed and operated Ge detectors underground at WIPP in low-background apparatus • Installed Ge detectors in clean room environment • Connected and tested associated electronics • Brought system to vacuum and cooled with LN • Collected 17-hour background run from three Ge detectors Steve Elliott

  31. Test Cryostat for String Design - Large cryostats • Detector String • Cryostat holds 3 strings - Each string holds 3 detectors • Strings hang inside detector hanger Goals • Study thermal properties of the Majorana crystal cooling design • Explore detector string design and mounting options • Operate a string of cooled detectors under vacuum Thermal Test Stainless steel “detector blanks” (above) similar thermal mass and emissivity of Ge crystals Thermocouples mounted on blanks and copper parts show temperature response when cooled (above) Successful cooling of blanks by weak conduction Steve Elliott

  32. 2 MeV DEP Survival: 59.7 ± 7.8% 2 MeV γ-Ray Survival: 27.9 ± 1.1% 3 MeV γ-Ray Survival: 28.5 ± 0.4% SEGA is the first seg. detector made from enriched 76Ge The FEL can be used as a tunable energy γ-ray source to get γ-rays and DEPs at Qββ What is the background discrimination power of PSA and segmentation for γ-ray and DEP events at Qββ? Demonstrated PSA in SEGA detector for the first time Used 6 x 2 (φx z) segmentation to examine survival probabilities for several segmentation schemes for DEP and γ-ray events Performance should improve after electronic and cryogenic upgrades HIγS FEL Runs to Characterize SEGA - background/detectors Steve Elliott

  33. Reference Design Backgrounds • Background modeling • Simulated major background sources for detector components in a 57-cystal array + shield using MaGe • Calculated total backgrounds individually for each detector technology under consideration • Results • Cu purity of ~0.3 mBq/kg is required; sizeable contribution from 208Tl in the cryostat and shield. • Higher rejection of segmented designs is roughly balanced by introduction of extra readout components. • P-PC appears to achieve the best backgrounds with minimal readout complexity. Steve Elliott

  34. Better Sensitivity – New Backgrounds Pb target in neutron beam arXiv:0809.5074 • Specific Pb gamma rays are problematic backgrounds • 206Pb has a 2040-keV γ ray • 207Pb has a 3062-keV γ ray • 208Pb has a 3060-kev γ ray • Neutron interactions in Pb can excite these levels • The DEP of the ~3062 keV γ ray is a single site energy deposit at ββ Q-value Steve Elliott

  35. Features Run time configuration, on-the-fly configurable acquisition tasks, run control, data monitoring, data replay capabilities, ROOT support. Real-time data stream can be broadcast to remote applications/machines Supports operator and expert user modes Object-oriented throughout (Objective-C), very modular, very easy to add new objects Uses XML for file headers and configuration storage Hardware Support VME, CAMAC, GPIB, cPCI, USB, IEEE 1394, Serial Usage SNO NCD, KATRIN pre-spect., CENPA accelerator, CENPA test stands, UW Radiology, MAJORANA(development), LANL, FZK test stands ORCA: Object-Oriented Real-time Control and AcquisitionHowe et al. IEEE Transactions on Nuclear Science, 51 (3), 878-83 Object Catalog Drag ‘n Drop to Place Objects Configuration View Steve Elliott

  36. GERDA MAJORANA MAJORANA - GERDA • Modules of enrGe housed in high-purity electroformed copper cryostat • Shield: electroformed copper / lead • Initial phase: R&D demonstrator module: Total ~60 kg (30 kg enr.) • ‘Bare’ enrGe array in liquid argon • Shield: high-purity liquid Argon / H2O • Phase I (late 2009): ~18 kg (HdM/IGEX diodes) • Phase II (mid 2009): add ~20 kg new detectors - Total ~40 kg • Joint Cooperative Agreement: • Open exchange of knowledge & technologies (e.g. MaGe, R&D) • Intention is to merge for 1 ton exp. Select best techniques developed and tested in GERDA and MAJORANA Steve Elliott

  37. The MAJORANACollaboration (Feb. 2009) Note: Red text indicates students • Black Hills State University, Spearfish, SD • Kara Keeter • Duke University, Durham, North Carolina , and TUNL • James Esterline, Mary Kidd, Werner Tornow • Institute for Theoretical and Experimental Physics, Moscow, Russia • Alexander Barabash, Sergey Konovalov, Igor Vanushin, Vladimir Yumatov • Joint Institute for Nuclear Research, Dubna, Russia • Viktor Brudanin, Slava Egorov, K. Gusey,OlegKochetov, M. Shirchenko, V. Timkin, E. Yakushev • Lawrence Berkeley National Laboratory, Berkeley, California andthe University of California - Berkeley • Mark Amman, Marc Bergevin, Yuen-Dat Chan, • Jason Detwiler, Brian Fujikawa, Kevin Lesko, James Loach, • Paul Luke, Alan Poon, Gersende Prior, Craig Tull, Kai Vetter, • Harold Yaver, Sergio Zimmerman • Los Alamos National Laboratory, Los Alamos, New Mexico • Steven Elliott, Victor M. Gehman, Vincente Guiseppe, • Andrew Hime, Kieth Rielage, Larry Rodriguez, Jan Wouters • North Carolina State University, Raleigh, North Carolina and TUNL • Henning Back, Lance Leviner, Albert Young • Oak Ridge National Laboratory, Oak Ridge, Tennessee • Jim Beene, Fred Bertrand, Thomas V. Cianciolo, Ren Cooper, • David Radford, Krzysztof Rykaczewski, Robert Varner, Chang-Hong Yu Osaka University, Osaka, Japan Hiroyasu Ejiri, Ryuta Hazama, Masaharu Nomachi, Shima Tatsuji Pacific Northwest National Laboratory, Richland, Washington Craig Aalseth, James Ely, Tom Farmer, Jim Fast, Eric Hoppe, Brian Hyronimus, Marty Keillor, Jeremy Kephart,Richard T. Kouzes, Harry Miley, John Orrell, Jim Reeves, Bob Thompson, Ray Warner Queen's University, Kingston, Ontario Art McDonald University of Alberta, Edmonton, Alberta Aksel Hallin University of Chicago, Chicago, Illinois Phil Barbeau, Juan Collar, Nicole Fields, Charles Greenberg, University of North Carolina, Chapel Hill, North Carolina and TUNL MelissaBoswell, Padraic Finnerty, Reyco Henning, Mark Howe, Michael Akashi-Ronquest, Sean MacMullin, Jacquie Strain, John F. Wilkerson University of South Carolina, Columbia, South Carolina Frank Avignone, Richard Creswick, Horatio A. Farach, Todd Hossbach University of South Dakolta, Vermillion, South Dakota Tina Keller, Dongming Mei, Chao Zhang University of Tennessee, Knoxville, Tennessee William Bugg, Yuri Efremenko University of Washington, Seattle, Washington John Amsbaugh, Tom Burritt, Peter J. Doe, Jessica Dunmore, Robert Johnson, Michael Marino, Mike Miller, Allan Myers, R. G. Hamish Robertson, Alexis Schubert, Tim Van Wechel

  38. DEMONSTRATOR Schedule 2015 Begin construction of 1-tonne Steve Elliott

  39. Summary • Primary focus is on first module, 18 BEGe’s • Much design work and prototyping in progress. • Final detector mount / cryostat design and readout down-select for first module in the summer • Sanford Lab preparations are proceeding rapidly, hope to begin installation late 2009 • Next collaboration meeting: June 2-4 at Sanford Lab in South Dakota Steve Elliott

  40. EXTRAS Steve Elliott

  41. MAJORANA technical progress - past year • Materials & Assay- Samples of low-activity plastics and cables have been obtained for radiometric counting and neutron activation analysis. Additional improvements have been gained in producing pure Cu through electroforming at PNNL and we have established an operating pilot program demonstrating electroforming underground at WIPP. • Ge Enrichment - Options available for germanium oxide reduction, Ge refinement, and efficient material recycling were considered. We have a plan to develop this capability located near detector fabrication facilities in Oak Ridge.  • Detectors- Additional p-type point contact (PPC) detectors have been ordered, using FY08 DUSEL R&D funds as well as LDRD or institutional funds. 18 of these detectors are intended for the “first cryostat”. Efforts to deploy a prototype low-background N-type segmented contact (NSC) detector using our enriched SEGA crystal are underway.  This will allow us to test low-mass deployment hardware and readout concepts while working in conjunction with a detector manufacturer.  • Cryostat Modules- A realistic prototype deployment system has been constructed at LANL.  Modifications to this design are in place to permit prototyping of the current string design. • DAQ & Electronics– Decision to use GRETINA digitizers. Preparing to place order. The slow control systems were exercised in a prototype deployment system at LANL. • Facilities- Designs for an underground electroforming facility at the 800’ level and a detector laboratory located on the 4850’ level in the Homestake Mine are nearly complete in collaboration with the Sanford Laboratory design team. The schedule indicates the labs should be ready near the end of CY2009. • Simulations- Several papers describing background studies have been published. • Management- Task specific groups have been formed based on revised R&D WBS.  Task leaders and their deputies have organized and held a number of workshops including Level 2 Task Leaders (Berkeley), Sanford/DUSEL planning (Lead, SD), Ge Enrichment (Oak Ridge), Cryostat Module (Seattle, Berkeley), Materials and Assay (Berkeley), and PPC Detectors (Oak Ridge). GERDA and MAJORANA collaborators have been attending the other collaboration’s meetings and updated the letter of intent to collaborate on a tonne-scale experiment. Steve Elliott

  42. Refinements to the MAJORANADemonstrator • Concentrate on P-PC Detectors. • Advantages of cost and simplicity, with no loss of physics reach. • Will continue N-SC R&D utilizing SEGA crystal. • Considering additional physics one can do with low-energy P-PC detectors. • exploits low-energy sensitivity (~100 eV threshold) of P-PC detectors • In joint partnership with agencies and institutions, plan early implementation of natural Ge P-PC sub-module. • Future commitments of institutional funds dependent on agency support. Steve Elliott

  43. The need for enriched 76Ge • Background Risks: • Achieving acceptable backgrounds in natGe detectors is a necessary, but not a sufficient condition to demonstrate our background goal • Past examples of significant background differences between natural and enriched detectors • Require backgrounds a factor of 100 below previous Ge experiments • At such levels, previously unanticipated background sources can arise • Require 60 kg of total Ge to establish background goal • 50% needs to be enriched to assure comparable background levels – 30 kg enrGe • Enrichment and purification can introduce impurities and physical differences that can impact subsequent chemistry • Require intrinsic enrGe detectors with isotopes of U and Th at the 10-15 g/g • Different isotopes of Ge have different cross-sections for cosmogenic activation • Cost Risks: • Must develop and maintain separate “production capabilities” for reduction of GeO2 to Ge metal; refinement to high purity Ge suitable for detector fabrication; successful detector fabrication • For 1-tonne it may be necessary to perform some of these steps UG • Conclusion: Must show in the Demonstrator phase that we can produce working enriched HPGe detectors with acceptable backgrounds. Steve Elliott

  44. ORTEC PPC prototype: >500 g Canberra BEGe for low-BG low-E studies Inverted-coax PPC Mini-PPCs for surface preparation studies Point contact Detectors Detectors in hand: Steve Elliott

  45. Front Ends: Resistive Feedback • Trace proximity provides ~1 pF capacitance • Silica or sapphire substrate provides thermal control • Amorphous Ge resistor: deposit in H environment gives proper R at low T • MX-120 FET • Possibility to add decoupling C inside feedback loop (substrate stands off HV) Steve Elliott 45

  46. Front-end and first stage “hybrid” design: close the loop near the detector Power dissipation and radioactivity levels may be challenging Currently prototyping Front Ends – Pulsed Reset COGENT front ends UW “Hybrid” Design Steve Elliott 46

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