KATRIN - Karlsruhe Tritium Neutrino Experiment - measuring sub-eV neutrino masses G. Drexlin, FZ...
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Transcript of KATRIN - Karlsruhe Tritium Neutrino Experiment - measuring sub-eV neutrino masses G. Drexlin, FZ...
KATRIN - Karlsruhe Tritium Neutrino Experiment -
measuring sub-eV neutrino masses
G. Drexlin, FZ Karlsruhe
for the KATRIN Collaboration
International Europhysics Conference on High Energy Physics EPS-HEP
Aachen, July 17-23, 2003
International Collaboration: 60 people, 12 institutions, 5 countries (CZ, D, RU, UK, US)
U Bonn – JINR Dubna* – Daresbury Lab – FH Fulda – U & Forschungszentrum
Karlsruhe – U Mainz – NPI Rez – RAL – UW Seattle – UW Swansea – INR Troitsk
- motivation
- major components : molecular tritium sources, spectrometers
- sensitivity & project schedule
Motivation I : particle physics
valididate or largely rule out models
w. quasi-degenerate mass eigenstates
Mixings and mass splittings by -oscillation studies,
fundamental -mass scale by ß-decay and 0ßß
KATRIN sensitivity
Science objectives of KATRIN
perform high resolution & high statistics
measurement of ß-spectrum
close to 18.6 keV endpoint of T2
mi [
eV]
Motivation II : cosmology
role of ‘s as hot dark matter –
fix or constrain m ()
S.W. Allen et al, astro-ph/0306386m = 0.7 eV (best fit)
Cosmological limits for m
are model-dependent:
D.N. Spergel et al, astro-ph/0302209
m < 0.69 eV (95%CL)
need lab measurement!
Science objectives of KATRIN
perform high resolution & high statistics
measurement of ß-spectrum
close to 18.6 keV endpoint of T2
status of present tritium experiments
Troitsk Mainz
gaseous T2-source quench-condensed solid T2-source
both experiments have reached their intrinsic limit of sensitivity
analysis 1994-99, 2001 analysis 1998/99, 2001
electrostatic retarding spectrometers with magnetic adiabatic collimation
see previous talk by Christine Kraus
experimental observable in ß-decay is m
aim : improve m by one order of magnitude (2 eV 0.2 eV )
requires : improve m by two orders of magnitude (4 eV2 0.04 eV2 )
problem : count rate close to ß-end point drops very fast (~E3)
last 10 eV : 2 x 10-10 / last 1 eV : 2 x 10-13 of total ß-activity
• improve statistics :
- stronger tritium source (factor 80) (& larger analysing plane, Ø=10m)
- longer measuring period (~100 days ~1000 days)
• improve energy resolution :
- large electrostatic spectrometer with E=1 eV (factor 4 improvement)
- reduce systematic errors :
- better control of systematics, energy losses (reduce to less than 1/10)
2
2
scaling factors for next-generation experiment
10 m 20 m 5 m 25 m 5m
KATRIN Layout
KATRIN will be located
on the site of FZK at
Tritium Laboratory Karlsruhe
TLK is worldwide unique,
for ITER tritium fuel cycle
TLK
1010 ß-decays/s
Main spectrometer – industrial design study
Stainless steel vessel ( Ø = 10 m & l = 22 m ) on HV potential,
minimisation of background rate : p < 10-11 mbar (XHV!)
main technological challenge of KATRIN,
addressed recently at X-VAT Workshop, Bad Liebenzell, April 2003
KATRIN Sensitivity
MC spectra for 3 years
with (bg) = 10 mHz:
statistical accuracy for
optimised measuring
point distribution:
(m2) = 0.013 eV2
m() < 0.146 eV (90%CL)
m() < 0.160 eV (95%CL)
all systematic errors :
(m2) = 0.011 eV2
statistical & systematic
errors contribute ~ equally
KATRIN Sensitivity
m() < 0.2 eV (90% CL)
no -mass signal –
KATRIN sensitivity :
evidence for-mass signal –
KATRIN discovery potential :
m() = 0.35 eV (5)
m() = 0.30 eV (3)
MC spectra for 3 years
with (bg) = 10 mHz:
1 2 3
3
2 1
KATRIN time schedule
1/2001 first presentation at internat. workshop Bad Liebenzell
6/2001 formal founding of KATRIN Collaboration
9/2001 submission of Letter of Interest (hep-ex 0109033)BMBF funding astroparticle physics
5/2002 International KATRIN review panel, UK joins Collaboration
2002-03 background studies, R&D works, design optimisation
5/2002 International KATRIN review panel, UK joins Collaboration
2003 Proposal submission, pre-spectrometer tests,tender for transport section & cryo supply,
KATRIN - hardware status
pre-spectrometer: first major KATRIN system component
will be operational soon with 2 superconducting magnets
vacuum and electromagnetic tests, background studies
inspection of weld seams
KATRIN time schedule
1/2001 first presentation at internat. workshop Bad Liebenzell
6/2001 formal founding of KATRIN Collaboration
9/2001 submission of Letter of Interest (hep-ex 0109033)BMBF funding astroparticle physics
5/2002 International KATRIN review panel, UK joins Collaboration
2002-03 background studies, R&D works, design optimisation
5/2002 International KATRIN review panel, UK joins Collaboration
2003 Proposal submission, pre-spectrometer tests,tender for transport section & cryo supply,
2003/04 funding applications & reviews: HGF, DOE, PPARC, RAS
2004-06 set up of T2 loop, transport section, spectrometer, detector
2006/07 commissioning of major components
2007 first measurements of entire system
Conclusions
KATRIN – a next generation tritium ß-decay experiment:
the only model-independent kinematic measurement with
sensitivity to sub-eV neutrino masses
- no signal: m< 0.2 eV (90% CL.) sensitivity
- signal : m = 0.35 eV @ 5 discovery potential
0.30 eV @ 3
first substantial funding: construction works have started !
tight project schedule with aim for first measurements 2007