the katrin experiment m. beck institut für kernphysik westfälische wilhelms-universität münster...
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The KATRIN experiment
M. Beck
Institut Für KernphysikWestfälische Wilhelms-Universität Münster
Wilhelm-Klemm-str. 948149 Münster
MotivationThe Experiment
Principle, Set-up, StatusSummary
The NeutrinomassExperimental detection of neutrino oscillations
Neutrinos have got mass
How large is m(e), what is the mass hierarchy?
-Oscillations7,310-5eV2 < m12
2 < 9.310-5eV2 solar
1,610-3eV2 < m232 < 3.610-3eV2 atm.
There is a with mi 0,009eV and one with mj 0,05eV
2. 0-decaym(e) 0,4 eV to be confirmed
3. Tritium -decaym(e)2 = -0,6 2,2 2,1 eV2 Mainz m(e) 2,3eV (95%)
4. CosmologymiO(1eV)
The Neutrinomass
Planned sensitivity of KATRIN: 0,2eV
Detection limit 0,3eV (3) / 0,35eV (5)
Tritium Decay: 3H3He+ + e- + e
Tritium -Decay
SuperallowedE0 = 18.6 keVt 1/2 = 12.3 a
dN/dE = K F(E,Z) p Etot (E0-Ee) |Uei|2 [ (E0-Ee)2 – m(i)2 ]1/2
The KATRIN experiment
Being set-up at the Forschungszentrum Karlsruhe
KArlsruhe TRItium Neutrinoexperiment
Principle: MAC-E Filter
Solid angle:
Up to 2
Adiabatic:
=E/B=const.
Resolution:
E/E=Bmin/Bmax
Bmax= 6T
Bmin 310-4T
E 1eV
The Tritium-Source: WGTSWGTS: Windowless Gaseous Tritium Source
Purpose:Tritium source with high and uniform intensity
Properties: = 9cm/L = 10m/B = 3,6T/ = 0,1%, T = 0,1K !!!Gas purity 95±1% T2 !!!T2-flow: 4,7Ci/s !!!
p(T2)max= 410-3mbarColumn density 51017 T2/cm2
1010 -decays/s
conzept:
2-Phasen Neon
(sied.
Flüssigkeit)2-phase Neon
beam pipe
Cu Tritium
heaters.c.Heliumvessel
Kr
The Tritium-source: WGTS
Pressure regulationtested successfully:testexperiment TILO
( constant at ‰ im level)
Status:Ordered
The transport section
Purpose:- Transport of the -Electrons to the spectrometers- Prevent the transport of T2 (Reduction of the flux of T2 by 1011 to 10-14 mbar l/s!!!)
Differential pumping sectionsDPS1-F, DPS2-FCryopumping sections
CPS1-F, CPS2-F
The transport section
Status:DPS2-F under constructionTRAP-experiment: cryosorption is working
Cryopumping:Cryosorption on Ar-snow
Testexperiment TRAP:
DPS2-F
The prespectrometer
Purpose:MAC-E filter for the suppression of -electrons with E<18,4keV
Fixed retardation potential of 18,4kV = 1,7m/L = 4,2m, Bmax= 4,5T, Bmin = 0.025TReduction of electron-flux 10-7
E 70-80eV
The prespectrometer at FZK
Since end of 2003 at the Forschungszentrum Karlsruhe
The prespectrometer at FZK
Wire electrode
NEG (10000l/s)
Status:Vaccuum tests successfull: p < 10-11 mbarEMD-test in progress since July 2006
The main spectrometer
Purpose:MAC-E filter for the precision measurement of the endpoint region of the Tritium -spectrum
Variable retardation potential 18,5-18,6kV=10m/L=23m, Bmax= 6T, Bmin = 310-4Tvacuum < 10-11mbar !!!E 1eV
An end section
Deggendorf, 14.3.2006Deggendorf, 14.3.2006
The spectrometer tank
Deggendorf, 14.3.2006Deggendorf, 14.3.2006June 2006
The wire elctrode
The wire electrode
5 x 20cylinder
3 x 20large cone
1 x 10small cone
Sum: 240 moduls!
The wire electrode
Single module:ca. 1.50 m x 1.80 m2 combs connectedvia 4 C-profiles
„Combs of stainlesssteel“:
Cut by water or laser
The wire electrode
C-profile
Comb1. layerØ 0.3 mm
2. layerØ 0.2 mm
70 m
m 25 mm
Prototype, U MünsterPrototype, U Münster
Prototype in Münster
The detector
Purpose:Position sensitive detectionof the electrons
Status:Under development
SegmentedSi-PIN diode
Detector of prespectrometer
Schedule
First components already set up at FZK:Prespectrometer → vacuum- and EMD-tests
Installation of the main spectrometer at FZKplanned for end of 2006
(Mass-)production of the wire electrode modulesin Münster in 2007 → installation end of 2007
Test measurements with a Krypton-source(U Münster) at the main spectrometer in 2008
Installation of the Tritium-source in 2008
Tritium measurements will start in 2010
Work on the building for the main spectrometer at FZK
SummaryThe aim of KATRIN is to search for the
neutrino mass in the region 0,2-2eV→ distinguish between hierarchical
and degenerate mass models
→ cosmologically relevant
For the specifications see KATRIN design report 2004 FZKA Scientific Report 7090
The main components are under construction
Measurements with KATRIN will start in 2010