the katrin experiment m. beck institut für kernphysik westfälische wilhelms-universität münster...

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