introduction experiment design sensitivity status and perspectives

Transcription

1 KATRIN Karlsruhe Tritium Neutrino Experiment direct measurement of the neutrino mass with sub-ev sensitivity Johannes (Hans) Blümer Universität Karlsruhe (TH) Forschungszentrum Karlsruhe Germany introduction experiment design sensitivity status and perspectives

2 some history

3 Wolfgang Pauli

4 Enrico Fermi

5 Reines and Cowan

6 Steinberger, Lederman, Schwartz

7 Salam, Weinberg, Glashow Proton Neutron

8 Davis, Koshiba, Giacconi

9

10 astroparticle physics is connecting quarks with the cosmos astroparticle theory gravitational waves nuclear astrophysics dark matter gamma rays neutrino properties (charged) cosmic rays low-energy astrophysical neutrinos high-energy astrophysical neutrinos

11 Astroparticle Physics 'connecting quarks with the cosmos' astroparticle theory gravitational waves nuclear astrophysics dark matter gamma rays neutrino properties (charged) cosmic rays low-energy astrophysical neutrinos high-energy astrophysical neutrinos

12 neutrino sources

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14

15

16

17 answers and questions

18 3 generations

19 fermion mass patterns the current range outdated

20 open questions Nuclear Physics what are the neutrino-nucleus cross-sections? Particle physics does CP violation in the neutrino sector exist? what are the precise values of oscillation parameters? do sterile neutrinos exist? are neutrinos Dirac or Majorana particles? Astrophysics what is the role of neutrinos in element synthesis? how do supernovae explode? Astroparticle physics, cosmology what is the neutrino fraction in Dark Matter? what is the role of neutrinos in structure formation? do ultra-high energy neutrinos exist? can we detect the big bang relic neutrinos? what are the absolute neutrino masses?

21 the neutrino mass

22 ν mass in cosmology hot dark matter: KATRIN: laboratory measurement of Ω ν cosmology: use LSS and CMBR to test Σm ν D.N. Spergel et al, Astrophys.J.Suppl. 148 (2003) 175 Σm ν < 0.69 ev (95%CL) S.W. Allen et al, astro-ph/ , MNRAS in press Σm ν = 0.56 ev (best fit value) these results are model-dependent

23 absolute scale of neutrino mass KATRIN scientific objective: model independent measurement of ν mass scale with sub-ev sensitivity for particle physics & cosmology quasidegenerate hierarchical 2 generic models of ν-masses

24 ν mass patterns

25 four methods for mν

26 beta decay experiments

27 beta decay oscillation experiments mass splittings Δm 2 ij & mixings sin2 (2θ ij ) beta decay kinematics model-independent mass value source: detection: high decay rate, low endpoint energy, superallowed transition, minimal inelastic electron scattering ev resolution, large solid angle, low background

28 electrostatic filters with magnetic guiding external ß- source: molecular tritium 3 H : E 0 =18.6 kev windowless gaseous or quenchcondensed T 2 ~ few Tesla ~few Gauss electrostatic spectrometer & magnetic adiabatic guiding integrated spectrum

29 Troitsk tritium experiment gas source analysis , 2001

30 Mainz tritium experiment quench-condensed solid source analysis 1998/9, 2001/2

31 KATRIN

32 programme context Helmholtz Association (FZK, FZJ, GSI, DESY,...) Energy Earth and Environment Health Key Technologies Transport and Space Structure of Matter Elementary Particle Physics Astroparticle Physics Galactic Cosmic Rays: KASCADE-Grande (Karlsruhe) Extragalactic cosmic rays: Pierre Auger Observatory (Argentina, USA) UHE Neutrino Astronomy: AMANDA, IceCube (Antarctica) Neutrino Mass and Dark Matter: KATRIN (Karlsruhe) Condensed Matter Hadrons and Nuclei Photons, Neutrons, Ions

33 the site Forschungszentrum Karlsruhe member of the Helmholtz Association 4 institutes on-site Tritium Laboratory Ka.: embedded into European fusion research

34 10 10 ß decays/s molecular tritium sources

35 windowless gaseous tritium source

36 source characteristics

37 differential pumping

38 cryo pumping

39 tandem electrostatic spectrometers

40 pre-spectrometer

41 pre-spectrometer

42 main spectrometer stainless steel vessel (Ø=10m & l=22m) on HV potential minimisation of background rate: p < mbar (UHV) inner surface ~ 800m 2 outgassing < mbar l / s volume to pump ~ 1500m 3 International X-VAT Workshop at Burg Bad Liebenzell, April 23-25, 2003

43 detector

44 sensitivity

45 sensitivity reference parameters

46 sensitivity simulated spectrum (1yr)

47 sensitivity statistical errors reference LoI 9/2001 design optimisations x stronger source Ø=75 90mm requires 10m Ø tank optimal HV points (~5 ev below E 0 ) background reduction by inner electrodes, low background detector (ongoing)

48 sensitivity discovery potential LoI 9/2001 statistical and systematic error will contribute about equally KATRIN sensitivity m(ν) < 0.2 ev (90% CL) reference KATRIN discovery potential m(ν) = 0.35 ev (5σ) m(ν) = 0.30 ev (3s)

49 sensitivity optimization improved statistics: source luminosity, scanning reduced systematics: ß-energy losses in source statistical and systematic error will contribute about equally KATRIN sensitivity m(ν) < 0.2 ev (90% CL) KATRIN discovery potential m(ν) = 0.35 ev (5σ) m(ν) = 0.30 ev (3s)

50 systematic uncertainties general relation for KATRIN statistics: Δ(m ν2 ) = 2 σ 2 syst inelastic scatterings of ß s in source (major uncertainty) requires dedicated e-gun measurements, unfolding techniques for response fct. HV stability of retarding potential on ~1ppm level required precision HV divider (PTB), monitor spectrometer beamline fluctuations of WGTS column density (required < 0.1%) rear detector, Laser-Raman spectroscopy, T=30K stabilisation WGTS charging due to remaining ions (MC: φ<20mv) inject low energy mev electrons from rear side, diagnostic tools available final state distribution reliable quantum chem. calculations, new calc. by J Tennyson (UCL)

51 source charging

52 the present status

53 present hardware

54 uhv test recipient tasks: a) validate XHV-techniques - sealings, surface preparations, pumps ( ) - thermal cycles ( ) b) training of XHV-personnel l=1.5m Ø=0.5m, V=0.3m_ - leak tests, XHV-measurements, cleanliness, c) test facility for XHV-materials - outgasing rates, XHV-compatibility Results: outgasing of stainless steel ( ) final pressure = 6 x mbar ( ) 500 mm flanges

55 pre-spectrometer IK/IEKP contributions: spectrometer vessel vacuum techniques techn. infrastructure & hall cooperation example ITP-contributions: superconduct. magnets magnetic field calculations vacuum techniques TLK contributions: electron gun calibration techniques safety & licensing contributions of collaborators inner electrode system (UW Seattle) electromagn. design (U Bonn/Mainz & FH Fulda) HV measurements & calibration (U Bonn) calibration devices (NPI Rez) IPE-contributions: Si-detector & electronics Slow Control System Data Acquisition System

56 pre-spectrometer delivery: Oct. 1, 2oo3 now: installation works for XHV tests, 1-6/04 vacuum tests, 6-12/04: em. Tests (e-gun)

57 collaboration and schedule

58 KATRIN Collaboration

59 organisation

60 Helmholtz KATRIN resources KATRIN Collaboration (~75 people) HGF funding profile KATRIN 7000 UW Swansea NPI Rez INR Troitsk U Mainz UW Seattle U Bonn Daresbury JINR k U Karlsruhe FH Fulda FZ Karlsruhe combined expertise of 4 FZK institutes IK - spectrometers, simulation, co-spokesperson ITP - magnets, vacuum, cryo supply, tech. coordination TLK - tritium handling & supply, safety IPE - electronics, DAQ & slow control Σ=21.6 M year investment granted by BMBF

61 schedule 1/2001 first presentation (internat. workshop Bad Liebenzell) 6/2001 formal founding of KATRIN Collaboration 9/2001 submission of Letter of Interest (hep-ex ) ~80 citations; BMBF funding astroparticle physics background studies, R&D works, design optimisation 5/2002 International KATRIN review panel, UK joins Collaboration 2003 pre-spectrometer tests, tenders for transport section and cryo supply; JLAB meets KATRIN at XVAT workshop 2003/04 funding applications & reviews: HGF, DOE, PPARC, RAS set up of T 2 source, transport section, spectrometer, detector 2007/8 commissioning & first test measurement

62 summary KATRIN reference design finished and optimised: sensitivity m ν < 0.2 ev (90%CL.), discovery m ν =0.35 ev (5σ) strong implications for cosmology (νhdm) & particle physics time critical: validate XHV-concept and novel electromagnetic design with prespectrometer (techn. manpower) detailed design specifications for magnet tenders KATRIN will need a high degree of control of systematic errors to develop new methods for calibration & monitoring (opportunities for new groups): QCTS, WGKrS, Am-Co ß-source,