Status and Perspectives of the KATRIN Experiment

Transcription

1 Status and Perspectives of the KATRIN Experiment for the KATRIN collaboration KIT University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

2 Outline Why are we interested in the absolute neutrino mass scale? How does KATRIN work and what is the status? Background at KATRIN Perspective of KATRIN Conclusion

3 Absolute neutrino mass scale Particle Physics Cosmology 336 relic n s/cm 3 dark energy dark matter baryons KATRIN stars gas

4 Outline Why are we interested in the abolute neutrino mass scale? How does KATRIN work and what is the status? Background at KATRIN Perspective of KATRIN Conclusion

5 KATRIN experiment - overview Goal: Direct neutrino mass measurement Sensitivity = 200 mev [90% C.L.] m 2 ( n ) e 3 i 1 U 2 ei m 2 i

6 KATRIN experiment - overview WGTS: Windowless gasseous tritium source Source mass: 0.3 mg of T 2 Yearly throughput 10 kg ( ITER) ß- intensity: electrons per second

7 Temperature T BT [K] KATRIN experiment - overview WGTS: Windowless gaseous tritium source h measurement KATRIN specification WGTS Demonstrator 06:00 07:00 08:00 09:00 10:00 arxiv: v1

8 KATRIN experiment - overview Transport section Transport section: 12 solenoids at 5.7 T Total KATRIN system: 37 solenoids

9 KATRIN experiment - overview Transport section R>10 7 R>10 7 p(t 2 ) < mbar p = mbar

10 KATRIN experiment - overview Transport section Differential pumping section + Cryogenic pumping section

11 KATRIN experiment - overview Transport section Differential pumping section + Cryogenic pumping section

12 potential [kv] KATRIN experiment - overview Pre- and main spectrometer distance from analyzing plane [m]

13 KATRIN experiment - overview Detector

14 KATRIN experiment - overview Detector

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16 KATRIN experiment - overview main spectrometer

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19 Outline Why are we interested in the abolute neutrino mass scale? How does KATRIN work and what is the status? Background at KATRIN Perspective of KATRIN Conclusion

20 Why is background an issue for KATRIN? Probability = electrons/s 10-2 electrons/s 1 electron/min

21 Background measurement at the prespectrometer

22 Background production mechanism t 1/2 ( 219 Rn) = 3.96 s Getter pump

23 Background production mechanism

24 Background production mechanism Northern lights

25 Background production mechanism

26 Verification of background model Comparison to independent measurement

27 Impact of background on KATRIN sensitivity arxiv: v1

28 Solution: Electron Cyclotron Resonance (ECR) RF cycl eb m

29 Solution: Electron Cyclotron Resonance (ECR) RF cycl eb m

30 Solution: Electron Cyclotron Resonance (ECR) cycl eb m

31 Solution: Electron Cyclotron Resonance (ECR)

32 Solution: Electron Cyclotron Resonance (ECR) arxiv: v1

33 Outline Why are we interested in the abolute neutrino mass scale? How does KATRIN work and what is the status? Background at KATRIN Perspective of KATRIN Conclusion

34 KATRIN and ev sterile neutrinos Reactor anomaly Gallium anomaly Short base line accelerator results

35 KATRIN and ev sterile neutrinos Reactor anomaly Gallium anomaly Short base line accelerator results sterile m s arxiv: v1

36 KATRIN and kev sterile neutrinos CDM predict too many satellite dwarf galaxies CDM WDM

37 KATRIN and kev sterile neutrinos CDM predict too many satellite dwarf galaxies n L, hot dark matter n R, warm dark matter candidate ~ 0, cold dark matter candidate ~ 1 ev ~ 1 kev ~ 1 TeV mass free ~ 1 Gpc ~ 10 kpc ~ 1 pc

38 KATRIN and kev sterile neutrinos M N 10 kev 20

39 Conclusion KATRIN Sensitivity of 200 mev Many major steps have been achieved Data taking will start in 2015 Background Stored electrons are a serious background source Electron Cyclotron Resonance to mitigate the problem Physics reach from sub-ev to kev neutrinos

40 Thank you for your attention

41 Backup slides

42 KATRIN and kev sterile neutrinos M sin N 2 10 kev 10 6 arxiv: v1

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

44 main spectrometer transport November 25, km voyage around Europe

45 LFCS EMCS large Helmholtz coil system main spectrometer vessel Ø = 12.7 m G. Drexlin VL0x KATRIN G. Drexlin KATRIN GDR Strasbourg 2009 G. Drexlin DPG2011

46 HV for KATRIN HV issues are of central importance for KATRIN: actual HV value defines the retarding potential for ß-decay electrons - HV fluctuations I: separate monitor beamline with nuclear standard 83m Kr - HV fluctuations II: ultra-precise HV divider with digital voltmeter

47 KATRIN HV divider ultra-precise HV divider for up to 65 kv U Münster and PTB Braunschweig (stored in steel cylinder in dry nitrogen gas) properties: - four scale factors: 100:1, 500:1, 1818:1, 3636:1-165 selected 880kW resistors (VISHAY) - resistors are pre-aged to reduce the long-term drift - temperature stabilisation DT < 0.1 K improved temperature regulation - HF-probe implemented KATRIN HV divider mark II

48 KATRIN sensitivity neutrino mass sensitivity: detailed investigations of of reference design, requirements: highest luminosity, high energy resolution, low background, control/monitoring of fluctuations near on-line MC of experim. data statistical & systematic errors are expected to contribute equally - statistical error s stat = ev 2 - systematic error s syst < ev 2 reference sensitivity (3 fb years) sensitivity (90% CL) m(n) < 200 mev discovery potential m(n) = 350 mev (5s)

49 m 2 sterile [ev 2 ] KATRIN sensitivity for sterile neutrinos Hannestad et al: initial estimates of KATRIN sensitivity for sterile n s assume very light active neutrinos m a (n) ~ 0 ev, mixed with sterile m s (n) 3 s detection of kink by m sterile if active-sterile mixing U es scenarios can also be disentangled preferred by reactor n anomaly 10 heavy sterile m a light active m a model: mixing U es 2 A.S. Riis, S. Hannestad, arxiv: v2, JCAP02(2011) s

50 Verification of background model Comparison to pre-spectrometer measurement from: vessel getter vessel