KATRIN: first tritium measurements Moriond EW 2019 Valérian 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 E
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
Introduction Tritium data Model components Fitting Conclusion From ν oscillations to mass scale Cosmology m 2 m 2 • Λ CDM ν e • � i m i < 0 . 12 − 1 eV ν µ ν τ 0 νββ 2 2 m 3 m 2 solar~7 × 10 − 5 eV 2 • Majorana phases 2 m 1 atmospheric • Matrix elements ~2 × 10 − 3 eV 2 atmospheric � i U 2 � < 0 . 2 − 4 eV � �� ~2 × 10 − 3 eV 2 • ei m i 2 m 2 solar~7 × 10 − 5 eV 2 2 2 m 1 m 3 β -decay & EC ? ? • Final states 0 0 �� i | U ei | 2 m i 2 < 2 eV • Valérian Sibille : MIT KATRIN: first tritium measurements 2 / 18
Introduction Tritium data Model components Fitting Conclusion KATRIN: m ν from β spectrum • Analyse electrons from molecular tritium β -decay m ν = 0.5 eV 2x10 -12 m ν = 0 eV T T 1.5x10 -12 φ (k e ) (/eV) + 3 He T 1x10 -12 5x10 -13 0 -1.4 -1.2 -1 -0.8 -0.6 -0.4 -0.2 0 k e - Q (eV) ⇒ Transport electrons ⇒ Select energy ⇒ Model comparison Valérian Sibille : MIT KATRIN: first tritium measurements 3 / 18
Introduction Tritium data Model components Fitting Conclusion Karlsruhe Tritium Neutrino experiment • 70 -metre beam-line • Gaseous T 2 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
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
Introduction Tritium data Model components Fitting Conclusion First tritium: commissioning phase 00:00 02:00 04:00 06:00 08:00 10:00 12:00 30.08 Temperature 30.07 30.06 (K) 30.05 • Injection: 18th May 2018 30.04 30.03 30.02 30.01 • Loop operation: 5th to Buffer pressure 18th June 2018 15.85 (mbar) 15.84 15.83 • 1% DT in D 2 15.82 15.81 15.80 • 0 . 1% stability DT concentration 1.1 • HeT + , T + , He + blocked (%) 1.0 0.9 0.8 00:00 02:00 04:00 06:00 08:00 10:00 12:00 Time (h) Valérian Sibille : MIT KATRIN: first tritium measurements 5 / 18
Introduction Tritium data Model components Fitting Conclusion Counting N electron hits • Set retarding potential U • Integrate over region of interest: N ( U ) FPD Event Rate (cps/0.1keV) 10 5 U = 16975V Region Of Interest U = 18275V 10 4 U = 18595V 10 3 10 2 10 1 10 0 10 -1 10 -2 10 -3 0 5 10 15 20 25 30 35 40 45 50 55 60 Energy (keV) ⇒ U, N ( U ) pairs define integrated β -spectrum Valérian Sibille : MIT KATRIN: first tritium measurements 6 / 18
Introduction Tritium data Model components Fitting Conclusion Integrated rate stability • Spectrometer retarding potential set 1 keV below endpoint • Rate averaged on minute-basis - σ + σ 80 Mean Count rate on detector (kcps) 20.95 70 60 20.90 + σ Frequency 50 Mean - σ 40 20.85 30 20.80 20 00:00 02:00 04:00 06:00 10 Time (h) 0 20.80 20.82 20.84 20.86 20.88 20.90 20.92 20.94 Count rate (kcps) ⇒ Stable over hours ⇒ Test analysis? Valérian Sibille : MIT KATRIN: first tritium measurements 7 / 18
Introduction Tritium data Model components Fitting Conclusion High-purity T 2 source: ongoing • Full column density & tritium purity > 95% ⇒× 200 June 2018 activity • Tested ion retention & background model • Optimise source parameters T 2 1.0 0.9 0.8 0.10 HT 0.05 DT 0.00 2000 2500 3000 3500 Raman shift (cm -1 ) Valérian Sibille : MIT KATRIN: first tritium measurements 8 / 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 8 / 18
Introduction Tritium data Model components Fitting Conclusion Tritium β -decay spectrum ���� ��� β ������� ����� � � �� � � ��� � �� �� �� • Super-allowed decay • Radiative corrections ���� ��� • 1 s screening • ... � � �� ��� ��� ��� • Roughly: ��������� ������� � � ��� �� � � � dΓ d E ∝ F ( E ) φ e ( E ) f ( V ) φ ν ( E + V )Θ( Q − E − V − m ν ) d V � ( Q − E ) 2 − m ν 2 φ ν ( E ) = ( Q − E ) Valérian Sibille : MIT KATRIN: first tritium measurements 9 / 18
Introduction Tritium data Model components Fitting Conclusion HeT or HeD molecules after decay • Spectrum f of excitations He • Theoretical work T • Significant 5-year systematic • Learn from data (spectroscopy, KATRIN, TRIMS) ���� � � � � �� ���� ����������� ���� ���� ���� � � � � � �� �� �� �� �� �� �� �� ����������� ������� � � ��� �� � Valérian Sibille : MIT KATRIN: first tritium measurements 10 / 18
Introduction Tritium data Model components Fitting Conclusion Magnetic Adiabatic Collimation & Electrostatic filter • Align electrons along electrostatic field B A � � • Select all signal electrons with E > qU A 1 + B max electrode system analysing plane electron trajectory magnet magnet source detector magnetic fieldlines B s B , U A B max A electron momentum vector Valérian Sibille : MIT KATRIN: first tritium measurements 11 / 18
Introduction Tritium data Model components Fitting Conclusion Scattering on source gas (T 2 , D 2 ) • Electron gun data (0 . 2 eV resolution) • Time of flight measurement 0.3 Energy loss function Aseev et al. parameterisation 2000 (T ) 2 Abdurashitov et al. parameterisation 2017 (D ) 2 0.25 KATRIN data 2018 (D ) 2 0.2 PRELIMINARY 0.15 0.1 2-fold 0.05 scattering 0 10 15 20 25 30 Electron energy loss (eV) ⇒ Refines KATRIN model Valérian Sibille : MIT KATRIN: first tritium measurements 12 / 18
Introduction Tritium data Model components Fitting Conclusion Response function: MAC-E filter & energy loss • Mitigate scattering with θ < 51 deg acceptance • Currently analysing T 2 scattering ��� � ��� ��������� ��������� ��� � ����� ��� � ������� � ���� ��� � �� �� �� �� �� �������� ������� � � ��� �� � � � ⇒ KATRIN model is semi-analytical (Kleesiek et al., EPJ C79 (2019) 204) Valérian Sibille : MIT KATRIN: first tritium measurements 13 / 18
Introduction Tritium data Model components Fitting Conclusion Backgrounds • Neutral Rydberg atoms (H ∗ ) • Optimise fiducial volume • 219 Rn from NEG pumps • N 2 -cooled 219 Rn traps x-position (m) MS H* 4 18.6 keV 2 − β FPD 0 − 2 5 eV e − − 4 − − − Kinetic energy (eV) 4 10 3 10 2 10 10 − 15 − 10 − 5 0 5 10 15 1 − 15 − 10 − 5 0 5 10 15 z-position (m) ⇒ Should reduce current 364 mcps ( ≫ 10 mcps from DR) Valérian Sibille : MIT KATRIN: first tritium measurements 14 / 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
Introduction Tritium data Model components Fitting Conclusion First 3h-run fit • Fit Endpoint, Normalisation, Background • Fix m 2 ν = 0 eV 2 • Poisson likelihood, statistical errors only, 400 eV range 1000 Fit result Count rate (cps) 750 Measurement 500 250 0 Norm. residuals 4 2 0 2 4 18200 18300 18400 18500 18600 Retarding energy (eV) ⇒ Solid model Valérian Sibille : MIT KATRIN: first tritium measurements 15 / 18
Introduction Tritium data Model components Fitting Conclusion Endpoint evolution • Fit 27 × 3 h runs with χ 2 KATRIN First Tritium Stat Fit: E0 Evolution (402eV below E0) 1 0.5 E0-<E0> (eV) 0 -0.5 -1 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 <p-value>=0.40 0.28 (std) = 0.28 eV 6 15 4 10 runs runs 2 5 0 0 0 10 20 30 40 50 -2 0 2 4 2 E0-<E0> / ⇒ Endpoint reproduced ⇒ Distributions exhibit no inconsistencies Valérian Sibille : MIT KATRIN: first tritium measurements 16 / 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 16 / 18
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