KATRIN: first tritium measurements Moriond EW 2019 Valrian Sibille, - - PowerPoint PPT Presentation

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KATRIN: first tritium measurements Moriond EW 2019 Valrian Sibille, - - PowerPoint PPT Presentation

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KATRIN: first tritium measurements Moriond EW 2019 Valrian Sibille, on behalf of the KATRIN collaboration MIT 19th March 2018 T R A I K N T K N A E R M L I S R R E U P H X E E T O R N I I T I R U U T M N

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SLIDE 1

KATRIN: first tritium measurements

Moriond EW 2019

Valérian Sibille, on behalf of the KATRIN collaboration

MIT

19th March 2018

K A T R I N

K A R L S R U H E T R I T I U M N E U T R I N O E X P E R I M E N T

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SLIDE 2

Introduction Tritium data Model components Fitting Conclusion

Outline

1 Introduction 2 Tritium data 3 Model components 4 Fitting 5 Conclusion

Valérian Sibille : MIT KATRIN: first tritium measurements 1 / 18

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SLIDE 3

Introduction Tritium data Model components Fitting Conclusion

From ν oscillations to mass scale

Cosmology

  • ΛCDM

i mi < 0.12 − 1 eV

0νββ

  • Majorana phases
  • Matrix elements
  • i U 2

eimi

  • < 0.2−4 eV

β-decay & EC

  • Final states
  • i |Uei|2mi2 < 2 eV

m2

solar~7×10−5eV2 atmospheric ~2×10−3eV2 atmospheric ~2×10−3eV2 m1

2

m2

2

m3

2

m2

m2

2

m1

2

m3

2

νe νµ ντ ? ? solar~7×10−5eV2

Valérian Sibille : MIT KATRIN: first tritium measurements 2 / 18

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SLIDE 4

Introduction Tritium data Model components Fitting Conclusion

KATRIN: mν from β spectrum

  • Analyse electrons from molecular tritium β-decay

3He

T T T

+ 5x10-13 1x10-12 1.5x10-12 2x10-12

  • 1.4
  • 1.2
  • 1
  • 0.8
  • 0.6
  • 0.4
  • 0.2

φ(ke) (/eV) ke - Q (eV) mν = 0.5 eV mν = 0 eV

⇒ Transport electrons ⇒ Select energy ⇒ Model comparison

Valérian Sibille : MIT KATRIN: first tritium measurements 3 / 18

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SLIDE 5

Introduction Tritium data Model components Fitting Conclusion

Karlsruhe Tritium Neutrino experiment

  • 70-metre beam-line
  • Gaseous T2 from Tritium Laboratory Karlsruhe (40 g d−1)
  • eV-resolution high-pass filter
  • 95%-efficiency Si-PIN diode wafer

Valérian Sibille : MIT KATRIN: first tritium measurements 4 / 18

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SLIDE 6

Introduction Tritium data Model components Fitting Conclusion

Outline

1 Introduction 2 Tritium data 3 Model components 4 Fitting 5 Conclusion

Valérian Sibille : MIT KATRIN: first tritium measurements 4 / 18

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SLIDE 7

Introduction Tritium data Model components Fitting Conclusion

First tritium: commissioning phase

  • Injection: 18th May 2018
  • Loop operation: 5th to

18th June 2018

  • 1% DT in D2
  • 0.1% stability
  • HeT+, T+, He+ blocked

00:00 02:00 04:00 06:00 08:00 10:00 12:00 30.01 30.02 30.03 30.04 30.05 30.06 30.07 30.08 15.80 15.81 15.82 15.83 15.84 15.85 00:00 02:00 04:00 06:00 08:00 10:00 12:00 0.8 0.9 1.0 1.1

Temperature (K) Buffer pressure (mbar) DT concentration (%) Time (h)

Valérian Sibille : MIT KATRIN: first tritium measurements 5 / 18

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SLIDE 8

Introduction Tritium data Model components Fitting Conclusion

Counting N electron hits

  • Set retarding potential U
  • Integrate over region of interest: N (U)

Region Of Interest

Energy (keV) FPD Event Rate (cps/0.1keV) 5 10 15 20 25 30 35 40 45 50 55 60 10-3 10-2 10-1 100 101 102 103 104 105 U = 16975V U = 18275V U = 18595V

⇒ U, N (U) pairs define integrated β-spectrum

Valérian Sibille : MIT KATRIN: first tritium measurements 6 / 18

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SLIDE 9

Introduction Tritium data Model components Fitting Conclusion

Integrated rate stability

  • Spectrometer retarding potential set 1 keV below endpoint
  • Rate averaged on minute-basis

00:00 02:00 04:00 06:00 20.80 20.85 20.90 20.95

Count rate on detector (kcps) Time (h)

  • σ

Mean + σ

20.80 20.82 20.84 20.86 20.88 20.90 20.92 20.94 10 20 30 40 50 60 70 80

+ σ

  • σ

Frequency Count rate (kcps) Mean

⇒ Stable over hours ⇒ Test analysis?

Valérian Sibille : MIT KATRIN: first tritium measurements 7 / 18

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SLIDE 10

Introduction Tritium data Model components Fitting Conclusion

High-purity T2 source: ongoing

  • Full column density & tritium purity > 95%

⇒×200 June 2018 activity

  • Tested ion retention & background model
  • Optimise source parameters

2000 2500 3000 3500 0.00 0.05 0.10 0.8 0.9 1.0

Raman shift (cm -1) T2 DT HT

Valérian Sibille : MIT KATRIN: first tritium measurements 8 / 18

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SLIDE 11

Introduction Tritium data Model components Fitting Conclusion

Outline

1 Introduction 2 Tritium data 3 Model components 4 Fitting 5 Conclusion

Valérian Sibille : MIT KATRIN: first tritium measurements 8 / 18

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SLIDE 12

Introduction Tritium data Model components Fitting Conclusion

Tritium β-decay spectrum

  • Super-allowed decay
  • Radiative corrections
  • 1s screening
  • ...
  • Roughly:
  • β
  • dΓ

dE ∝ F(E) φe(E)

  • f(V ) φν(E + V )Θ(Q − E − V − mν) dV

φν(E) = (Q − E)

  • (Q − E)2 − mν 2

Valérian Sibille : MIT KATRIN: first tritium measurements 9 / 18

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Introduction Tritium data Model components Fitting Conclusion

HeT or HeD molecules after decay

  • Spectrum f of excitations
  • Theoretical work
  • Significant 5-year systematic
  • Learn from data (spectroscopy, KATRIN, TRIMS)

He T

  • Valérian Sibille : MIT

KATRIN: first tritium measurements 10 / 18

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SLIDE 14

Introduction Tritium data Model components Fitting Conclusion

Magnetic Adiabatic Collimation & Electrostatic filter

  • Align electrons along electrostatic field
  • Select all signal electrons with E > qUA
  • 1 +

BA Bmax

  • source

detector magnet magnet electron trajectory analysing plane electrode system magnetic fieldlines Bs B ,

A

Bmax electron momentum vector UA

Valérian Sibille : MIT KATRIN: first tritium measurements 11 / 18

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SLIDE 15

Introduction Tritium data Model components Fitting Conclusion

Scattering on source gas (T2, D2)

  • Electron gun data (0.2 eV resolution)
  • Time of flight measurement

10 15 20 25 30

Electron energy loss (eV)

0.05 0.1 0.15 0.2 0.25 0.3

Energy loss function

)

2

Aseev et al. parameterisation 2000 (T )

2

Abdurashitov et al. parameterisation 2017 (D )

2

KATRIN data 2018 (D

PRELIMINARY

2-fold scattering

⇒Refines KATRIN model

Valérian Sibille : MIT KATRIN: first tritium measurements 12 / 18

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Introduction Tritium data Model components Fitting Conclusion

Response function: MAC-E filter & energy loss

  • Mitigate scattering with θ < 51 deg acceptance
  • Currently analysing T2 scattering
  • ⇒ KATRIN model is semi-analytical (Kleesiek et al., EPJ C79 (2019) 204)

Valérian Sibille : MIT KATRIN: first tritium measurements 13 / 18

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Introduction Tritium data Model components Fitting Conclusion

Backgrounds

  • Neutral Rydberg atoms (H∗)
  • 219Rn from NEG pumps
  • Optimise fiducial volume
  • N2-cooled 219Rn traps

− − −

4 − 2 − 2 4

x-position (m)

−

β 18.6 keV

−

e 5 eV FPD MS

15 − 10 − 5 − 5 10 15

15 − 10 − 5 − 5 10 15

z-position (m)

1 10

2

10

3

10

4

10 Kinetic energy (eV)

H*

⇒Should reduce current 364 mcps (≫ 10 mcps from DR)

Valérian Sibille : MIT KATRIN: first tritium measurements 14 / 18

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SLIDE 18

Introduction Tritium data Model components Fitting Conclusion

Outline

1 Introduction 2 Tritium data 3 Model components 4 Fitting 5 Conclusion

Valérian Sibille : MIT KATRIN: first tritium measurements 14 / 18

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Introduction Tritium data Model components Fitting Conclusion

First 3h-run fit

  • Fit Endpoint, Normalisation, Background
  • Fix m2

ν = 0 eV2

  • Poisson likelihood, statistical errors only, 400 eV range

250 500 750 1000 Count rate (cps) Fit result Measurement 18200 18300 18400 18500 18600 Retarding energy (eV) 4 2 2 4

  • Norm. residuals

⇒ Solid model

Valérian Sibille : MIT KATRIN: first tritium measurements 15 / 18

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Introduction Tritium data Model components Fitting Conclusion

Endpoint evolution

  • Fit 27 × 3 h runs with χ2

40667 40668 40669 40670 40671 40672 40673 40674 40675 40676 40677 40678 40679 40680 40681 40682 40683 40684 40685 40686 40687 40688 40689 40690 40691 40692 40693

run

  • 1
  • 0.5

0.5 1 E0-<E0> (eV) <p-value>=0.40 0.28 (std) 10 20 30 40 50

2

2 4 6 runs = 0.28 eV

  • 2

2 4 E0-<E0> / 5 10 15 runs KATRIN First Tritium Stat Fit: E0 Evolution (402eV below E0)

⇒ Endpoint reproduced ⇒ Distributions exhibit no inconsistencies

Valérian Sibille : MIT KATRIN: first tritium measurements 16 / 18

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SLIDE 21

Introduction Tritium data Model components Fitting Conclusion

Outline

1 Introduction 2 Tritium data 3 Model components 4 Fitting 5 Conclusion

Valérian Sibille : MIT KATRIN: first tritium measurements 16 / 18

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Introduction Tritium data Model components Fitting Conclusion

Conclusion & prospects

Running T2 experiment Tested data analysis framework Blind analysis Optimise source & spectrometer parameters Refine systematics Complete mν campaign Sub-eV sensitivity soon

Valérian Sibille : MIT KATRIN: first tritium measurements 17 / 18

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Introduction Tritium data Model components Fitting Conclusion

Thank you

Thank you for your attention

Valérian Sibille : MIT KATRIN: first tritium measurements 18 / 18