single ß-decay experiments: overview and KATRIN

Transkript

1 single ß-decay experiments: overview and KATRIN ß-decay & ν-mass p tritium experiments KATRIN a MAC MAC--E filter project p j status ν 1 G. Drexlin EKP VL

2 neutrino oscillations: 3-flavour mixing 3-flavour oscillations decouple into three separate mixing terms: 0 0 cosθ13 1 U = 0 cosθ 23 sin θ 23 0 iδ 0 sin sin i θ cos θ i θ e δ: CP-phase 0 sin i θ13e iδ cosθ12 sin i θ sin θ12 cosθ cosθ &&2. 3. Generation generation 1. & 3. generation 1. & 2. generation atmospheric ν s solar / reactor neutrinos solar neutrinos long baseline reactor/accelerators reactor experiments long baseline accelerators νµ - x G. Drexlin KIT-EKP ISAPP νµ - ντ _ νe x νµ - νe νe - x _ νe x

3 neutrino oscillations: 3-flavour mixing 3-flavour oscillations decouple into three separate mixing terms: U iδδ cos θ 13 0 sinθ13e cos θ12 sin θ12 0 = 0 cosθ23 sinθ sinθ12 cosθ12 0 iδ 0 sinθ23 cosθ23 sinθ13e 0 cosθ δ: CP-Phase & Generation generation 1. & 3. generation 1. & 2. generation Δm 232 = ev 2 Δm 132 = ev 2 Δm 122 = ev 2 θ 23 = (45 ± 4) (maximum) θ 13 < 15 (very small) θ 23 = (33.7±1.3) (large) Δm 2 23 Δm 2 13 Δm tan 2 θ 23 sin 2 θ 13 tan 2 θ 12 G. Drexlin KIT-EKP ISAPP

4 neutrino masses in particle physics normal hierarchy with m 1 < m 2 < m 3 ν mass [ev] quasi-degenerated mass models ν 3 atmospheric solar ν 2 ν 1 solar atmospheric hierarchical mass models?? ν mass offset? absolute scale m 1? G. Drexlin KIT-EKP ISAPP

5 neutrino masses in particle physics normal hierarchy with m 1 < m 2 < m 3 quasi-degenerated scenario quasi-degenerated mass models hierarchical scenario hierarchical mass models G. Drexlin KIT-EKP ISAPP

6 neutrino masses in particle physics normal hierarchy with m 1 < m 2 < m 3 quasi-degenerated mass models flavour composition of mass eigenstates hierarchical mass models G. Drexlin KIT-EKP ISAPP

7 neutrino mass: status and perspectives kinematics of ß-decay absolute ν e -mass mass: :m ν model-independent status: m ν < 2.3 ev potential: m ν = 200 mev KATRIN (MARE-II) search for 0νßß eff ff. Majorana mass m ßß model-dependent (CP-phases) status: m ßß < 0.35 ev, evidence? potential: m ßß = mev GERDA, EXO, CUORE neutrino masses experimental techniques: status & potential cosmology sum Σm i, HDM Ω ν model-dependent d d (multi-parameter t fits) status: Σm i < 1 ev [Hannestad et al., arxiv: v2] potential: Σm i = mev Planck, LSST, weak lensing

8 Majorana and Dirac neutrinos what is the intrinsic particle-antiparticle symmetry of neutrinos? ν L Dirac neutrino Lorentz 4 ν states lepton number ν D conservation ΔL = 0 neutrino antineutrino CPT CPT ν L _ ν R _ ν L ν R Majorana neutrino Lorentz 2 ν states t lepton number violation ΔL =2 ν M ν L ν R ν D and ν M only distinguishable if m ν 0 CPT

9 Majorana and Dirac neutrinos what is the intrinsic particle-antiparticle symmetry of neutrinos? ν L ν L _ ν R Lorentz _ ν L ν R CPT CPT Lorentz ν L ν R CPT

10 ß-decay: Fermi s theory & ν-mass a model-independent measurement of m(ν e ) based on kinematics & energy conservation ) ( i i ei e m m U = = ν ) ( ), ( ) ( ) ( ) ( d i i i m E E Z E F m E E E E m E p C + = Γ θ based on kinematics & energy conservation 1 i incoherent sum ) ( ), ( ) ( ) ( ) ( d i i e m E E Z E F m E E E E m E p C E + θ (ν mass) 2 hi h i t? ( ) which isotope?

11 ß-decay: energy spectrum ( ei mi a model-independent measurement of m(ν e ) m ν e ) = U based on kinematics & energy conservation i= 1 dγi = de C p ( E m ) ( E E ) ( E E ) m F ( E, Z ) θ ( E e incoherent sum E m 0 0 i 0 i ) ß-source requirements short half life t ½ high luminosity low endpoint energy E 0 superallowed/allowed transition simple atomic/molecular structure (ν mass) 2 ß-detection requirements large solid angle (~2π) low background rate high energy resolution (~ev) short dead time, no pile up 3 H: super-allowed E kev t 12 3 y 187 Re: unique 1 st E kev calorimeter ß-source =detector spectrometer external ß-source t / y t 1/ Gy ß-source: Re ß-source: H

12 techniques in ß-decay the two different techniques are complementary due to different systematics calorimeter spectrometer source metallic Re / dielectric AgReO 4 windowless gaseous / condensed T 2 activity low: <10 5 ß/s, ~ 1 Bq / mg Re high: ~10 11 ß/s, 4.7 Ci/s injection energy single crystal bolometers electrostatic spectrometer response entire ß-decay energy kinetic energy of ß-decay electrons interval entire spectrum very narrow interval close to E 0 method differential energy spectrum integrated energy spectrum set-up modular size, scaling factors integral design, size limits resolution ΔE expected ~ 5-10 ev (FWHM) ΔE expected ~ 0.93 ev (100%) MARE KATRIN

13 history of tritium ß-decay experiments experimental results for m ν 2 < 2.3 ev < 2.3 ev

14 Troitsk & Mainz experiments Troitsk experiment windowless gaseous tritium source analysis of data , 99, 2001 Mainz experiment quench condensed tritium source analysis of data , 2001

15 spectrometers comparison of techniques Tret yakov detector source Δp/p = δω = 10-3 magnetic guiding field: momentum analysis U 0 MAC-E ΔE/E = δω ~ 2 π source detector magnetic guiding field & conversion, cyclotron motion electric retarding field: energy analysis

16 MAC-E filter principle MAC Magnetic Adiabatic Guiding adiabatic guiding of electrons along magnetic field lines inhomogenous B-field: superconducting solenoids B max = 3 6 T B min < 1 mt solid angle dω ~ 2π r r r r r F = μ B + q E μ = ( ) E E / B = const. T 2 source s.c. solenoid adiabatic transformation E E s.c. solenoid detector

17 MAC-E filter principle E Filter Electro- static filter energy analysis by an electrostatic t ti retarding field variable E-field: inner electrodes U 0 = kv integral transmission for E>U 0 high pass filter Efi field ld Bfi B-field T 2 source s.c. solenoid HV electrodes s.c. solenoid detector conversion retarding adiabatic transformation E E

18 KATRIN B-field & electrostatic potential 1 tritium source spectrometer B max [T] B-field po otential [kv V] steep gradients B min distance from analysing plane [m]

19 KATRIN B-field & gyroradius tritium source 1 spectrometer [T] B-field gyr ro radius [m m] electron gyroradius: 10-2 r g =33µm 3.3 p [kev] / B [T] distance from analysing plane [m]

20 KATRIN experiment - overview tritium-bearing components electrostatic spectrometers & detector improve experim. precision i by factor 100 ( go to the technological l limits ) it fully adiabatic (mev-skala) particle transport over > 50 m Bq tritium source 10-2 Bq total background

21 KATRIN closed tritium cycle & TLK KATRIN tritium throughput per year equivalent to fusion facility ITER KATRIN closed cycle operational in 2012 first D-T operation of ITER in 2026 TLK Tritium Laboratory Karlsruhe a unique research facility in Europe licensed for storage of 20 g tritium

22 KATRIN closed tritium cycle KATRIN tritium loop system 27 pumps, 109 valves, 62 sensors, 6 buffer vessels, 2 permeators CMS-R 5% 95% DPS1-R WGTS DPS1-F DPS2-F inner loop control system T 2 injection 95% 5% CPS batch mode, 60 days (<1 Ci) 1% outer loop T 2 preparation isotope separation 1% outer loop T 2 retention- system

23 KATRIN closed tritium cycle KATRIN tritium loop system 27 pumps, 109 valves, 62 sensors, 6 buffer vessels, 2 permeators set-up of inner loop system in progress

24 KATRIN Laser Raman Spectroscopy high-precision (~0.1%) in-situ measurement of 200 actual H-isotopologue composition in the WGTS T 2 D intensit ty [arb. units] wavelength [nm]

25 WGTS windowless gaseous source tritium source WGTS design value precision luminosity Bq injection rate mol/s ±0.1 1% column density ρd mol/cm 2 ±0.1 % tritium purity > 95% ±0.1 % magnetic field 3.6 T ± 2%

26 WGTS windowless gaseous source tritium source 12 cryogenic circuits 6 cryogenic fluids - instrumentation: ~ 500 sensors for temperature (4 600 K), B-field, pressure, gas flow, liquid levels

27 KATRIN windowless gaseous source WGTS gasdynamics: on-going detailed modelling of molecular velocities T 2 T 2 T 2 T 2 T 2 T 2 P in = mbar TMP MAG 2800

28 KATRIN tritium retention the tritium flow out of the WGTS has to be reduced by factor ~10 14 tritium bearing components tritium free WGTS DPS2-F CPS spectrometers bar] p [10-3 m injection injection rate = 1.8 mbar l / s differential cryogenic pumping p p(t < ) mbar R>10 7 R> mbar l/s mbar l/s

29 differential pumping section DPS2-F active tritium pumping with 4 TMP s DPS2-F TMP #4 ß s TMP #1 T 2

30 July 14, 2009: DPS2-F cryostat has arrived at KIT campus north

31 differential pumping section DPS2-F 2010 DPS2-F experimental programme - verify H-isotopologue retention R = investigations of ion properties: - diagnostics with FT-ICR measurements - suppression with dipoles

32 cryogenic pumping section CPS CPS UHV pumping- duct DN100 77K 77K cold valve DN 150 RT objective: reduction of T 2 -flux by factor 10 7 : 10-7 mbar l/s mbar l /s method: cryo-sorption on condensing Ar-frost T 2 -rate: <1 Ci T 2 in 60 days = 1 KATRIN run (regeneration with warm He-gas) argon frost pump T = 3 45K 4.5 presently being manufactured by ASG

33 cryogenic pumping section CPS CPS RT UHV pumping- duct DN100 77K cold valve DN K argon frost pump T = 3 45K 4.5

34 electrostatic spectrometers UHV p < mbar pre-filter fixed retarding potential U 0 = kv ΔE ~ 100 ev - filter out all ß-decay electrons without m(ν)-info - reduce background from ionising collisions no info on m(ν) precision filter - scanning variable retarding potential U 0 = kv ΔE ~ 0.93 ev (100% transmission) tandem design: pre-filter & energy analysis

35 pre-spectrometer UHV UHV p < mbar successful verification of UHV concept SAES getters

36 pre-spectrometer: electromagnetic tests optimisation of electromagnetic design - minimisation of Penning traps - background reduction techniques (dipole fields) - study of field emission diameter = 1.7m length = 3.4m Si-PIN e-gun

37 pre-spectrometer: electromagnetic tests 360mm U < 0V magnetic field 310mm optimisation of electromagnetic design GND - design of geometry of ground & Anti-Penning electrodes - detailed d study of characteristics ti of fpenning traps as function of electrostatic potential, B-field, pressure - 3 rd generation layout is being implemented

38 main spectrometer: world s largest UHV recipient Helmholtz- coils UHV : p < mbar! Helmholtz coils vessel on HV dimensions: diameter: 10 m length: 23.3 m surface: 690 m 2 volume: 1240 m 3 38 G. Drexlin G. Drexlin KIT- IK & EKP ISAPP July 22, 2009

39 main spectrometer: world s largest UHV recipient LHC accelerator KATRIN Volume pressure spectrometer 1250 m mbar LHC Volume pressure storage ring 154 m mbar cryogenic insulation 640 m mbar method turbomolecular pumps / nonevaporable getters method cryocondensation on beam screen/magnet bore (1.9K) cryocondensation on magnet cold mass KATRIN spectrometer VIRGO antennae LIGO Volume pressure method 2x4km arms 8000 m 3 ~10-8 mbar ion pumps & cold traps VIRGO Volume pressure method 2x3km arms 6800 m 3 <10-9 mbar titanium & ion pumps ps

40 main spectrometer: pre-acceptance tests August TMP (WMAG2800) p < 6 x 10-8 mbar initial integral He-leak test at MAN-DWE

41 main spectrometer: transport

42 main spectrometer: transport start: Oct 2006 Deggendorf MAN-DWE manufacture hall

43 main spectrometer: transport

44 main spectrometer: transport

45 the final 7km: passing Leopoldshafen November 25, 2006: after an 8800 km sea-going voayge the main Spectrometer was manoeuvred by an SPMT over 7km to the final destination at the KATRIN experimental halls ( visitors) arrival at Leimersheim ferry & reloading onto SPMT with heavy-duty crane In pictures: photos of the year 2006 SPMT

46 the final 7m, initial out-baking & UHV July 2007: initial UHV tests of vessel after out-baking with 6 TMPs steam blasting outgassing rate [ T = 20 C ] mbar l / cm 2 s p = mbar H 2 0 H 2 November 29, 2006 temperature distribution vessel at T = 350 C

47 inner electrodes: motivation & tasks #1: fine forming of electrostatic retarding field - precision HV power supplies: intrinsic HV precision ~1 ppm - dipole mode: emptying of particles stored in Penning traps #2: background suppression inelastic reactions of cosmic muons low-energy secondary electrons from the 690 m 2 inner surface d=22cm =15cm d vessel wall ΔU 1 = 100 V background reduction: factor wire plane #1 ΔU 2 = 200 V 2 wire plane #2 47 G. Drexlin EKP VL

48 inner electrodes: overall system layout shallow cone 3x20 modules cylindrical part 5x20 modules steep cone 1x10 module 1x4 module module manufacture at U Münster

49 inner electrodes: mounting system mounting system - access via 85 m 2 clean room at rear end - electropolished mounting system for precise mounting - laser tracker alignment with 100 µm over entire inner surface

50 July 2009: first wire modules installed successfully

51 main spectrometer UHV p < mbar air coils (LFCS) E(e - ) = U 0-1 ev for better visualisation of cyclotron motion set m e = 0.01 m e

52 main spectrometer: Helmholtz coil system LFCS Low Field Coil System radial coils tasks: - constrain magnetic flux tube (2.4 G 3.4 G) - reduce field inhomogeneities (33% 13%) EMCS Earth Magnetic Field Coil System cosine coils tasks: - compensate earth magnetic field (500 mg) or B-field distortions 02/09-08/09: assembly Ø=12.6m

53 earth magnetic field position: latitude N longitude E h = 115 m earth magnetic field: International Geomagnetic Reference Field (IGRF 10) field parameter value for 7/2009 yearly change inclination declination absolute field strength nt 34.3 nt vertical component nt 32.1 nt horizontal component nt 12.3 nt horizontal field north nt 11.3 nt horizontal field east nt 42.9 nt 1 G = nt 1% of 3 G = 3000 nt

54 Helmholtz coil system status July y m 12.6

55 focal plane system pinch magnet provide maximum field B max = 6 T (bore 340mm) - guiding g B-field in rear spectrometer part - define θ max for ß-electrons in WGTS - define energy resolution spectrometer detector magnet strong field B det = 3 6 T (bore 440 mm) - optimised focusing of analysing plane inhomogeneities (B, U 0 ) focal plane detector t segmented Si-PIN diode array read-out electronics

56 focal plane detector monolithic segmented Si-PIN diode array: - counting of transmitted ß-decay electrons - determination of radial position r & azimuth angle φ of ß-electrons to correct for electrostatic & magnetic inhomogeneities in analysing plane

57 detector system present hardware status

58 background sources tritium source - ß-decay electrons from areas with different electrostatic potentials - ß-decays from T - /T + iones detector - X-rays, gammas & electrons from natural radioactivity or scattered ß-decay electrons (beam-halo) total bg -rate = 10 mhz R bg spectrometer - stored ß-electrons (Penning traps) - low-energy shake off electrons from T 2 -ß-decays in central spectrometer area - cosmic induced secondary electrons

59 systematic effects Δm 2 ν = 2 2σ syst general relation for tritium-ß-decay inelastic scattering of ß-decay electrons in the WGTS - dedicated measurements with electron gun, special unfolding techniques HV-stabilisation of spectrometer retarding potential - precision-hv-divider (calibrated by PTB) & digital voltmeter - monitor spectrometer (Mainz) & atomic/nuclear standard (Rb/Kr-source) fluctuations of the WGTS column densitiy ρd (required <10-3 ) - stabilisation of ρd: injection pressure, beam tube T=27K, Laser-Raman - measurements electron gun, rear monitor detector/system charging effects in the WGTS - neutralise remaining ions in WGTS (Φ <20mV) mv), injection of mev-e e - distribution of final states (molecular excitations in 3 H 3 He) - reliable quantumchemical calculations, very good agreement

60 measurement intervals & spectra optimised HV scanning procedure, parameter decorrelation by 3 regions Region I: E «E 0 determine E 0 from fit procedure (ΔE 0 ~ 3 mev) Region II: E ~ ev maximum sensitivity for m(ν) with S/B-ratio~2 Region III: E > E 0 determine background rate (aim for 10 mhz) I II III retarding potential [ev] retarding potential [ev]

61 KATRIN sensitivity ν-mass sensitivity for 3 full beam measuring years ity / disc covery potential [σ] Sensitiv reference setup 2004 statistical & systematic errors contribute equally: - statistical error σ stat = ev 2 - systematic error σ syst < ev 2 sensitivity (90% CL) m(ν) < 200 mev discovery potential ti m(ν) = 350 mev (5σ) ν-mass m ν [ev]

62 KATRIN impact on astroparticle physics cosmic architects: fix relic-ν role as hot dark matter microscopic c keys: fix generic e neutrino mass pattern tritium ß-decay dark energy dark matter baryons KATRIN stars gas ν oscillations KATRIN : a key experiment for astroparticle physics

63 KATRIN Collaboration uniting the world-wide expertise in tritium ß-decay experiments: ~140 Collaboration members (12 institutions from D, USA, GB, CZ, Russia) ~ 60% from KIT pool of expertise (IK, EKP, ITP/TLK, IPE) 2012: begin of T 2 measurements 2008