Seminar Construction and operation of the Bern EXO - 100 cryogenic - PowerPoint PPT Presentation

Seminar Construction and operation of the Bern “EXO - 100” cryogenic facility for R&D in liquid xenon: advances in barium ion tagging Sébastien Delaquis University of Bern Switzerland SLAC, 17th November 2015

Outline Double-beta decay ( ββ )  a way to address some of the open questions in the neutrino sector The Enriched Xenon Observatory (EXO)  EXO’s approach to address the challenge  the concept of barium ion tagging – open R&D questions Advances in barium ion tagging: • Analysis of alpha decays with EXO-200 data  ion properties relevant for ion tagging in liquid xenon • The EXO-100 facility  construction and operation of a cryogenic R&D facility 2

Neutrino physics: status quo Measured with neutrino oscillation experiments: 3 mixing angles 2 Δ𝑛 2 Open questions in the neutrino sector: • Mass hierarchy • Absolute neutrino masses • Nature of neutrino mass (Dirac, Majorana) • CP violation in the lepton sector • Massive sterile neutrinos Sébastien Delaquis – Seminar, SLAC, 17th November 2015 3

Double-beta decay: determining the absolute neutrino mass Search for neutrinoless double-beta decay  sensitive to Majorana neutrinos 2 2 2 = 2 𝑛 𝑗 𝑉 𝑓𝑗 2 𝑓 𝜷 𝒋 𝑛 𝑗 𝑛 𝛾𝛾 𝑉 𝑓𝑗 = 𝑗 𝑗 Direct neutrino mass determination: 2(eff) = • Kinematics of weak decays 𝑉 𝑓𝑗 2 𝑛 𝜉 𝑗 2 𝑛 𝜉 𝑓 𝑗 • Time-of-flight measurment (supernova) 𝑁 = 𝑛 𝜉 𝑗 Measurements of the anisotropies of the primordial 𝑗 microwave background Sébastien Delaquis – Seminar, SLAC, 17th November 2015 4

Double-beta decay: decay modes Two neutrino double-beta decay ( 2νββ ) • Allowed by the SM of particle physics • Observed in 11 isotopes so far: 𝟐𝟒𝟕 𝒀𝒇: 𝟔𝟓 2𝜉𝛾𝛾 = 2.165 ± 0.016 𝑡𝑢𝑏𝑢 ± 0.059 𝑡𝑧𝑡 10 21 yr 𝑈 1/2 EXO Collaboration: Phys. Rev. C 89, 015502 (2014) As a comparison the age of the universe: (13.798 ± 0.037) 10 9 yr This is the most precisely measured half-life of any 2 nbb decay to 2νββ: 2𝑜 0 → 2𝑞 + + 2𝑓 − + 2 𝜉 𝑓 date. Moreover, this is the slowest process ever directly observed by mankind! Sébastien Delaquis – Seminar, SLAC, 17th November 2015 5

Double-beta decay: decay modes Neutrinoless double-beta decay ( 0νββ ) • Only allowed if the neutrino is a Majorana particle! Violating total lepton number: Δ𝑀 = 2 • • Hypothetical process: not observed so far (one controversal claim). 1 2 0𝜉 = 𝐻 0𝜉 𝑁 0𝜉 2 𝑛 𝛾𝛾 𝑈 0νββ: 2𝑜 0 → 2𝑞 + + 2𝑓 − 1/2 𝐻 0𝜉 phase space factor 𝑁 0𝜉 nuclear matrix element 𝑛 𝛾𝛾 effective neutrino mass Sébastien Delaquis – Seminar, SLAC, 17th November 2015 6

Double-beta decay: decay modes Seperating 0νββ from 2νββ 0νββ: 2𝑜 0 → 2𝑞 + + 2𝑓 − 2νββ: 2𝑜 0 → 2𝑞 + + 2𝑓 − + 2 𝜉 𝑓 Energy resolution is essential! Sébastien Delaquis – Seminar, SLAC, 17th November 2015 7

Double-beta decay: candidate isotopes Realistically observable only in a few even-even nuclei (35 naturaly occuring isotopes). Q-value Sargent’s rule: decay rate ∝ Q 5 • • backgrounds Natural abundance of the isotope and 𝐵, 𝑎 → 𝐵, 𝑎 − 2 + 2𝑓 − + 2 2𝜉𝛾𝛾: 𝜉 𝑓 ease of enrichment A suited detection technique • source as detection medium • easy to purify (nat. rad.) Sébastien Delaquis – Seminar, SLAC, 17th November 2015 8

Double-beta decay: detection technique cathode at high voltage e- e- e- e- e- Electric field e- charge read-out system PMTs for scintillation light Sébastien Delaquis – Seminar, SLAC, 17th November 2015 23

Double-beta decay: ββ experiments 76 Ge: γ Advantage of xenon TPC: GERDA • segmentation 130 Te: CUORE 𝛿 𝛾 136 Xe: multi site (MS) single site (SS) EXO KamLand-Zen • good energy resolution • Others: unique capability to identify the decay product; NEMO barium tagging Sébastien Delaquis – Seminar, SLAC, 17th November 2015 10

University of Alabama, Tuscaloosa AL, USA - D. Auty, T. Didberidze, M. Hughes, A. Piepke, R. Tsang University of Bern, Switzerland - S. Delaquis, R. Gornea, T. Tolba, J-L. Vuilleumier California Institute of Technology, Pasadena CA, USA - P. Vogel Multi stage project: Carleton University, Ottawa ON, Canada - V. Basque, M. Dunford, K. Graham, C. Hargrove, R. Killick, T. Koffas, F. Leonard, C. Licciardi, M.P. Rozo, D. Sinclair Colorado State University, Fort Collins CO, USA - C. Benitez-Medina, C. Chambers, A. Craycraft, W. Fairbank, Jr., T. Walton Drexel University, Philadelphia PA, USA - M.J. Dolinski, M.J. Jewell, Y.H. Lin, E. Smith, Y.-R Yen • EXO-200 Duke University, Durham NC, USA - P.S. Barbeau IHEP Beijing, People ’ s Republic of China - G. Cao, X. Jiang, L. Wen, Y. Zhao • University of Illinois, Urbana-Champaign IL, USA - D. Beck, M. Coon, J. Ling, M. Tarka, J. Walton, L. Yang nEXO Indiana University, Bloomington IN, USA - J. Albert, S. Daugherty, T. Johnson, L.J. Kaufman University of California, Irvine, Irvine CA, USA - M. Moe • nEXO with barium tagging ITEP Moscow, Russia - D. Akimov, I. Alexandrov, V. Belov, A. Burenkov, M. Danilov, A. Dolgolenko, A. Karelin, A. Kovalenko, A. Kuchenkov, V. Stekhanov, O. Zeldovich Laurentian University, Sudbury ON, Canada - B. Cleveland, A. Der Mesrobian-Kabakian, J. Farine, B. Mong, U. Wichoski University of Maryland, College Park MD, USA - C. Davis, A. Dobi, C. Hall University of Massachusetts, Amherst MA, USA - J. Abdollahi, T. Daniels, S. Johnston, K. Kumar, A. Pocar, D. Shy University of Seoul, South Korea - D.S. Leonard SLAC National Accelerator Laboratory, Menlo Park CA, USA - M. Breidenbach, R. Conley, A. Dragone, K. Fouts, R. Herbst, S. Herrin, A. Johnson, R. MacLellan, K. Nishimura, A. Odian, C.Y. Prescott, P.C. Rowson, J.J. Russell, K. Skarpaas, M. Swift, A. Waite, M. Wittgen Stanford University, Stanford CA, USA - J. Bonatt, T. Brunner, J. Chaves, J. Davis, R. DeVoe, D. Fudenberg, G. Gratta, S.Kravitz, D. Moore, I. Ostrovskiy, A. Rivas, A. Schubert, D. Tosi, K. Twelker, M. Weber Technical University of Munich, Garching, Germany - W. Feldmeier, P. Fierlinger, M. Marino TRIUMF, Vancouver BC, Canada – J. Dilling, R. Krucken, F. Retière, V. Strickland Sébastien Delaquis – Seminar, SLAC, 17th November 2015 11

The Enriched Xenon Observatory: EXO-200 set-up Located at WIPP in New Mexico, 655 m.w.e below ground Sébastien Delaquis – Seminar, SLAC, 17th November 2015 12

The Enriched Xenon Observatory: EXO-200 results Expected background Th-232 chain : 16.0 U-238 chain : 8.1 Xe-137 : 7.0 Total expected: 31.1 ± 3.8 Total observed: 39 Best fit for 0 nbb : 9.9 2𝜉𝛾𝛾 = 2.165 ± 0.016 𝑡𝑢𝑏𝑢 ± 0.059 𝑡𝑧𝑡 10 21 yr 𝑈 1/2 EXO Collaboration: Phys. Rev. C 89, 015502 (2014) 0𝜉𝛾𝛾 > 1.1 10 25 yr at 90% C. L. 𝑈 1/2 EXO Collaboration: Nature (London) 510, 299-234 (2014) Sébastien Delaquis – Seminar, SLAC, 17th November 2015 13

The Enriched Xenon Observatory: EXO-200 performance Sébastien Delaquis – Seminar, SLAC, 17th November 2015 14

The Enriched Xenon Observatory: nEXO A single TPC 5 tn of enriched xenon Operational in ~2020 Sébastien Delaquis – Seminar, SLAC, 17th November 2015 15

The Enriched Xenon Observatory: nEXO expected performence How can we further increase sensitivity? Make it HUGE?!?... Not possible because of: Ba tagging • xenon world production • 𝟐𝟒𝟕 𝑪𝒃 ++ + 2𝑓 − (+2 enrichment rate 136 𝑌𝑓 𝜉 𝑓 ) • cost… 54 𝟔𝟕 𝛿 -line of 214 Bi within 10keV of the Q-value • Sébastien Delaquis – Seminar, SLAC, 17th November 2015 16

The Enriched Xenon Observatory: expected performence of nEXO w. Ba tagging Advantage of barium tagging: tag all backgrounds not related to ββ • • ultimate background 2νββ Sébastien Delaquis – Seminar, SLAC, 17th November 2015 17

The Enriched Xenon Observatory: barium tagging technique Ba + grabber probe cavity ionizer mass filter ion trap e- e- e- e- e- e- CCD Sébastien Delaquis – Seminar, SLAC, 17th November 2015 18

The Enriched Xenon Observatory: barium tagging technique Ba + grabber probe cavity ionizer mass filter ion trap e- e- e- e- e- e- CCD Sébastien Delaquis – Seminar, SLAC, 17th November 2015 19

The Enriched Xenon Observatory: polonium tagging 218 Po decay 222 Rn decay Sébastien Delaquis – Seminar, SLAC, 17th November 2015 20

The Enriched Xenon Observatory: polonium tagging technique Ba + grabber probe 218 Po decay alpha detector e- e- e- 222 Rn decay e- e- e- Sébastien Delaquis – Seminar, SLAC, 17th November 2015 21

The Enriched Xenon Observatory: steps towards barium / polonium tagging Important properties of the decay product • fraction of ions • drift speed • neutralisation during drift Need for a test set-up: • cryostat • TPC • displacement device • ion grabbing probe → requires that barium is ionized!!! Sébastien Delaquis – Seminar, SLAC, 17th November 2015 22

Analysis of alpha decays with EXO-200 data: concept Important properties of the decay product • fraction of ions • drift speed • neutralisation during drift Sébastien Delaquis – Seminar, SLAC, 17th November 2015 23