scholarly journals Quantitative Long-Term Monitoring of the Circulating Gases in the KATRIN Experiment Using Raman Spectroscopy

Sensors ◽  
2020 ◽  
Vol 20 (17) ◽  
pp. 4827 ◽  
Author(s):  
Max Aker ◽  
Konrad Altenmüller ◽  
Armen Beglarian ◽  
Jan Behrens ◽  
Anatoly Berlev ◽  
...  
Keyword(s):  
Neutrino Mass ◽  
Electron Neutrino ◽  
Effective Electron ◽  
Term Operation ◽  
Laser Raman ◽  
Gaseous Tritium ◽  
Order Of Magnitude ◽  
Recording Analysis ◽  
Katrin Experiment

The Karlsruhe Tritium Neutrino (KATRIN) experiment aims at measuring the effective electron neutrino mass with a sensitivity of 0.2 eV/c2, i.e., improving on previous measurements by an order of magnitude. Neutrino mass data taking with KATRIN commenced in early 2019, and after only a few weeks of data recording, analysis of these data showed the success of KATRIN, improving on the known neutrino mass limit by a factor of about two. This success very much could be ascribed to the fact that most of the system components met, or even surpassed, the required specifications during long-term operation. Here, we report on the performance of the laser Raman (LARA) monitoring system which provides continuous high-precision information on the gas composition injected into the experiment’s windowless gaseous tritium source (WGTS), specifically on its isotopic purity of tritium—one of the key parameters required in the derivation of the electron neutrino mass. The concentrations cx for all six hydrogen isotopologues were monitored simultaneously, with a measurement precision for individual components of the order 10−3 or better throughout the complete KATRIN data taking campaigns to date. From these, the tritium purity, εT, is derived with precision of <10−3 and trueness of <3 × 10−3, being within and surpassing the actual requirements for KATRIN, respectively.

scholarly journals The Neutrino Mass Experiment KATRIN

2019 ◽  
Vol 64 (7) ◽  
pp. 573
Author(s):  
F. M. Fraenkle
Keyword(s):  
Neutrino Mass ◽  
Large Scale ◽  
Mass Measurement ◽  
Current Status ◽  
Effective Electron ◽  
Segmented Detector ◽  
Decay Spectroscopy ◽  
Gaseous Tritium ◽  
Scale Experiment ◽  
Katrin Experiment

The KArlsruhe TRItium Neutrino (KATRIN) experiment is a large-scale experiment with the objective to determine the effective electron antineutrino mass in a model-independent way with an unprecedented sensitivity of 0.2 eV/c2 at 90% C.L. The measurement method is based on the precision B-decay spectroscopy of molecular tritium. The experimental setup consists of a high-luminosity windowless gaseous tritium source, a magnetic electron transport system with differential cryogenic pumping for the tritium retention, and an electrostatic spectrometer section for the energy analysis, followed by a segmented detector system for the counting of transmitted B-electrons. The first KATRIN neutrino mass measurement phase started in March 2019. Here, we will give an overview of the KATRIN experiment and its current status.

scholarly journals Gamma-induced background in the KATRIN main spectrometer

2019 ◽  
Vol 79 (9) ◽  
Author(s):  
K. Altenmüller ◽  
M. Arenz ◽  
W.-J. Baek ◽  
M. Beck ◽  
A. Beglarian ◽  
...  
Keyword(s):  
Experimental Tests ◽  
Effective Electron ◽  
Background Rate ◽  
Electron Antineutrino ◽  
Plane Detector ◽  
Gaseous Tritium ◽  
Background Events ◽  
Gamma Flux ◽  
Katrin Experiment ◽  
Focal Plane Detector

Abstract The KATRIN experiment aims to measure the effective electron antineutrino mass $$m_{\overline{\nu }_e}$$mν¯e with a sensitivity of $${0.2}\,{\hbox {eV}/\hbox {c}^2}$$0.2eV/c2 using a gaseous tritium source combined with the MAC-E filter technique. A low background rate is crucial to achieving the proposed sensitivity, and dedicated measurements have been performed to study possible sources of background electrons. In this work, we test the hypothesis that gamma radiation from external radioactive sources significantly increases the rate of background events created in the main spectrometer (MS) and observed in the focal-plane detector. Using detailed simulations of the gamma flux in the experimental hall, combined with a series of experimental tests that artificially increased or decreased the local gamma flux to the MS, we set an upper limit of $${0.006}\,{\hbox {count}/\hbox {s}}$$0.006count/s (90% C.L.) from this mechanism. Our results indicate the effectiveness of the electrostatic and magnetic shielding used to block secondary electrons emitted from the inner surface of the MS.

scholarly journals Precision measurement of the electron energy-loss function in tritium and deuterium gas for the KATRIN experiment

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
M. Aker ◽  
A. Beglarian ◽  
J. Behrens ◽  
A. Berlev ◽  
U. Besserer ◽  
...  
Keyword(s):  
Energy Loss ◽  
Neutrino Mass ◽  
Loss Function ◽  
Precision Measurement ◽  
Measurement Data ◽  
Gas Mixture ◽  
Systematic Effect ◽  
Effective Electron ◽  
Energy Loss Function ◽  
Katrin Experiment

AbstractThe KATRIN experiment is designed for a direct and model-independent determination of the effective electron anti-neutrino mass via a high-precision measurement of the tritium $$\upbeta $$ β -decay endpoint region with a sensitivity on $$m_\nu $$ m ν of 0.2 $$\hbox {eV}/\hbox {c}^2$$ eV / c 2 (90% CL). For this purpose, the $$\upbeta $$ β -electrons from a high-luminosity windowless gaseous tritium source traversing an electrostatic retarding spectrometer are counted to obtain an integral spectrum around the endpoint energy of 18.6 keV. A dominant systematic effect of the response of the experimental setup is the energy loss of $$\upbeta $$ β -electrons from elastic and inelastic scattering off tritium molecules within the source. We determined the energy-loss function in-situ with a pulsed angular-selective and monoenergetic photoelectron source at various tritium-source densities. The data was recorded in integral and differential modes; the latter was achieved by using a novel time-of-flight technique. We developed a semi-empirical parametrization for the energy-loss function for the scattering of 18.6-keV electrons from hydrogen isotopologs. This model was fit to measurement data with a 95% $$\hbox {T}_2$$ T 2 gas mixture at 30 K, as used in the first KATRIN neutrino-mass analyses, as well as a $$\hbox {D}_2$$ D 2 gas mixture of 96% purity used in KATRIN commissioning runs. The achieved precision on the energy-loss function has abated the corresponding uncertainty of $$\sigma (m_\nu ^2)< {{10}^{-2}}{\hbox {eV}^{2}}$$ σ ( m ν 2 ) < 10 - 2 eV 2 [1] in the KATRIN neutrino-mass measurement to a subdominant level.

scholarly journals First direct neutrino-mass measurement with sub-eV sensitivity

2021 ◽  
Author(s):  
M. Aker ◽  
M. Bottcher ◽  
A. Beglarian ◽  
J. Behrens ◽  
A. Berlev ◽  
...  
Keyword(s):  
Neutrino Mass ◽  
Precision Measurement ◽  
Mass Measurement ◽  
Β Decay ◽  
High Precision Measurement ◽  
Effective Electron ◽  
Upper Limit ◽  
Neutrino Mass Measurement ◽  
Katrin Experiment ◽  
Best Fit

Abstract We report the results of the second measurement campaign of the Karlsruhe Tritium Neutrino (KATRIN) experiment. KATRIN probes the effective electron anti-neutrino mass, mν, via a high-precision measurement of the tritium β-decay spectrum close to its endpoint at 18.6 keV. In the second physics run presented here, the source activity was increased by a factor of 3.8 and the background was reduced by 25% with respect to the first campaign. A sensitivity on mν of 0.7 eV/c2 at 90% confidence level (CL) was reached. This is the first sub-eV sensitivity from a direct neutrino-mass experiment. The best fit to the spectral data yields mν2=(0.26±0.34) eV2/c4, resulting in an upper limit of mν<0.9 eV/c2 (90% CL). By combining this result with the first neutrino mass campaign, we find an upper limit of mν<0.8 eV/c2 (90% CL).

scholarly journals Data reduction for a calorimetrically measured $$^{163}\mathrm {Ho}$$ spectrum of the ECHo-1k experiment

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
Robert Hammann ◽  
Arnulf Barth ◽  
Andreas Fleischmann ◽  
Dennis Schulz ◽  
Loredana Gastaldo
Keyword(s):  
Electron Capture ◽  
Neutrino Mass ◽  
Data Reduction ◽  
Time Profile ◽  
Electron Neutrino ◽  
Effective Electron ◽  
Trigger Time ◽  
Pile Up ◽  
Time Information

AbstractThe electron capture in $$^{163}\mathrm {Ho}$$ 163 Ho experiment (ECHo) is designed to directly measure the effective electron neutrino mass by analysing the endpoint region of the $$^{163}\mathrm {Ho}$$ 163 Ho electron capture spectrum. We present a data reduction scheme for the analysis of high statistics data acquired with the first phase of the ECHo experiment, ECHo-1k, to reliably infer the energy of $$^{163}\mathrm {Ho}$$ 163 Ho events and discard triggered noise or pile-up events. On a first level, the raw data is filtered purely based on the trigger time information of the acquired signals. On a second level, the time profile of each triggered event is analysed to identify the signals corresponding to a single energy deposition in the detector. We demonstrate that events not belonging to this category are discarded with an efficiency above 99.8%, with a minimal loss of $$^{163}\mathrm {Ho}$$ 163 Ho events of about 0.7%. While the filter using the trigger time information is completely energy independent, a slight energy dependence of the filter based on the time profile is precisely characterised. This data reduction protocol will be important to minimise systematic errors in the analysis of the $$^{163}\mathrm {Ho}$$ 163 Ho spectrum for the determination of the effective electron neutrino mass.

scholarly journals High-resolution and low-background $$^{163}$$Ho spectrum: interpretation of the resonance tails

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
C. Velte ◽  
F. Ahrens ◽  
A. Barth ◽  
K. Blaum ◽  
M. Braß ◽  
...  
Keyword(s):  
Electron Capture ◽  
Neutrino Mass ◽  
Line Shape ◽  
High Energy ◽  
Electron Neutrino ◽  
High Energy Resolution ◽  
Precise Description ◽  
Effective Electron ◽  
Low Background ◽  
The Impact

AbstractThe determination of the effective electron neutrino mass via kinematic analysis of beta and electron capture spectra is considered to be model-independent since it relies on energy and momentum conservation. At the same time the precise description of the expected spectrum goes beyond the simple phase space term. In particular for electron capture processes, many-body electron-electron interactions lead to additional structures besides the main resonances in calorimetrically measured spectra. A precise description of the $$^{163}$$163Ho spectrum is fundamental for understanding the impact of low intensity structures at the endpoint region where a finite neutrino mass affects the shape most strongly. We present a low-background and high-energy resolution measurement of the $$^{163}$$163Ho spectrum obtained in the framework of the ECHo experiment. We study the line shape of the main resonances and multiplets with intensities spanning three orders of magnitude. We discuss the need to introduce an asymmetric line shape contribution due to Auger–Meitner decay of states above the auto-ionisation threshold. With this we determine an enhancement of count rate at the endpoint region of about a factor of 2, which in turn leads to an equal reduction in the required exposure of the experiment to achieve a given sensitivity on the effective electron neutrino mass.

scholarly journals Constraints on the Active and Sterile Neutrino Masses from Beta-Ray Spectra: Past, Present and Future1

2016 ◽  
Vol 3 (1) ◽  
pp. 73-113 ◽  
Author(s):  
Otokar Dragoun ◽  
Drahoslav Vénos
Keyword(s):  
Neutrino Mass ◽  
Sterile Neutrino ◽  
Electron Neutrino ◽  
Neutrino Masses ◽  
Effective Electron ◽  
Upper Limit ◽  
Cosmological Observations ◽  
Two Generations ◽  
Experimental Approaches ◽  
The Universe

Although neutrinos are probably the most abundant fermions of the universe their mass is not yet known. Oscillation experiments have proven that at least one of the neutrino mass states hasmi> 0.05 eV while various interpretations of cosmological observations yielded an upper limit for the sum of neutrino masses ∑mi< (0.14 ‒ 1.7) eV. The searches for the yet unobserved 0νββ decay result in an effective neutrino massmββ< (0.2 ‒ 0.7) eV. The analyses of measured tritium β-spectra provide an upper limit for the effective electron neutrino massm(ve) < 2 eV. In this review, we summarize the experience of two generations of β-ray spectroscopists who improved the upper limit ofm(ve) by three orders of magnitude. We describe important steps in the development of radioactive sources and electron spectrometers, and recapitulate the lessons from now-disproved claims for the neutrino mass of 30 eV and the 17 keV neutrino with an admixture larger than 0.03%. We also pay attention to new experimental approaches and searches for hypothetical sterile neutrinos.

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