Dynamic Raman spectroscopy of hydrogen isotopomer mixtures in-line at TILO

Lewis, Richard J.; Telle, Helmut H.; Bornschein, B.; Kazachenko, O.; Kernert, N.; Sturm, M.

doi:10.1002/lapl.200810026

Cited by 20 publications

(19 citation statements)

References 19 publications

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“…The Raman gas cell is the same cell we have used in all our previous measurements, which is tritium compatible and is based on the design by Taylor et al . For measurements using tritium‐containing isotopologues, the cell has to be placed into a secondary safety enclosure, which requires that the laser beam (and the Raman scattered light) has to pass through additional windows.…”

Section: Methodsmentioning

confidence: 99%

Accurate depolarization ratio measurements for all diatomic hydrogen isotopologues

James

Schlösser

Fischer

et al. 2013

J Raman Spectroscopy

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The Raman depolarization ratios for individual Q1(J”) branch lines of all diatomic hydrogen isotopologues – H2, HD, D2, HT, DT, and T2 – were measured, for all rotational levels with population larger than 1/100 relative to the Boltzmann maximum at room temperature. For these measurements, the experimental setup normally used for the monitoring of the tritiated hydrogen molecules at KArlsruhe TRItium Neutrino experiment was adapted to optimally control the excitation laser power and polarization, and to precisely define the Raman light collection geometry. The measured Raman depolarization values were compared to theoretical values, which are linked to polarizability tensor quantities. For this, the ‘raw data’ were corrected taking into account distinct aspects affecting Raman depolarization data, including (1) excitation polarization impurities; (2) extended Raman excitation volumes; and (3) Raman light collection over finite solid angles. Our corrected depolarization ratios of the hydrogen isotopologues agree with the theoretical values (based on ab initio quantum calculations by R.J. LeRoy, University of Waterloo, Canada) to better than 5% for nearly all of the measured Q1(J”) lines, with 1σ confidence level. The results demonstrate that reliable, accurate Raman depolarization ratios can be extracted from experimental measurements, which may be substantially distorted by excitation polarization impurities and by geometrical effects. Copyright © 2013 John Wiley & Sons, Ltd.

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Section: Methodsmentioning

confidence: 99%

Accurate depolarization ratio measurements for all diatomic hydrogen isotopologues

James

Schlösser

Fischer

et al. 2013

J Raman Spectroscopy

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“…The different tritiated gas species (T 2 , DT, HT) have to be distinguished not only because of their different properties in the gas dynamical calculations, but also due to their slightly different endpoint energies as well as rotational and vibrational final states. Test measurements with a Raman cell suitable for operation with tritium [118,119] show that a precision of ∆ prec ( T 2 )/ T 2 = 0.1% for T 2 monitoring can be achieved in measurement intervals of < 250 s under KATRIN operating conditions [120,121]. With an optimized setup the acquisition time recently has been reduced to 60 s only.…”

Section: The Wgts Cryostat and Associated Control And Monitoring Systemsmentioning

confidence: 99%

Current Direct Neutrino Mass Experiments

Drexlin

Hannen

Mertens

et al. 2013

Advances in High Energy Physics

288

304

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In this contribution we review the status and perspectives of direct neutrino mass experiments. These experiments investigate the kinematics of β-decays of specific isotopes ( 3 H, 187 Re, 163 Ho) to derive model-independent information on the averaged electron (anti-) neutrino mass, which is formed by the incoherent sum of the neutrino mass eigenstates contributing to the electron neutrino. We first review the kinematics of β-decay and the determination of the neutrino mass, before giving a brief overview of past neutrino mass measurements (SN1987a-ToF studies, Mainz and Troitsk experiments for 3 H, cryo-bolometers for 187 Re). We then describe the Karlsruhe Tritium Neutrino (KATRIN) experiment which is currently under construction at Karlsruhe Institute of Technology. The large-scale setup will use the MAC-E-Filter principle pioneered earlier to push the sensitivity down to a value of 200 meV (90% C.L.). KATRIN faces many technological challenges that have to be resolved with regard to source intensity and stability, as well as precision energy analysis and low background rate close to the kinematic endpoint of tritium β-decay at 18.6 keV. We then review new experimental approaches such as the MARE, ECHO and Project8 experiments, which offer the promise to perform an independent measurement of the neutrino mass in the sub-eV region. This variety of methods and the novel technologies developed in all present and future experiments demonstrate the great potential of direct neutrino mass experiments in providing vital information on the absolute mass scale of neutrinos.

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“…The concept of the laser Raman (LARA) monitoring system is shown in Figure 2 . The setup follows closely that originally proposed in the KATRIN Design Report [ 13 ]; its capabilities were successfully demonstrated in 2008 during the “TILO” (Test of Inner LOop) experiment [ 28 ], to ascertain that the inner loop functioned correctly and fulfilled all design specifications. It should be noted that those tests were performed without the WGTS, which was still under construction at that time.…”

Section: Setup and Methodsmentioning

confidence: 99%

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

Aker

Altenmüller

Beglarian

et al. 2020

Sensors

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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.

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Dynamic Raman spectroscopy of hydrogen isotopomer mixtures in-line at TILO

Cited by 20 publications

References 19 publications

Accurate depolarization ratio measurements for all diatomic hydrogen isotopologues

Accurate depolarization ratio measurements for all diatomic hydrogen isotopologues

Current Direct Neutrino Mass Experiments

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

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