Fusion facilities like ITER and DEMO will circulate huge amounts of deuterium and tritium in their fuel cycle with an estimated throughput of kg per hour. One important capability of these fuel ...cycles is to separate the hydrogen isotopologues. For this purpose the Isotope Separation System (ISS), using cryogenic distillation, as part of the TRitium Enrichment Test Assembly (TRENTA) is under development at Tritium Laboratory Karlsruhe. Fourier transform infrared absorption spectroscopy (FTIR) has been selected to prove its capability for inline monitoring of the tritium concentration in the liquid phase at the bottom of the distillation column of the ISS. The actual R&D work is focusing on the calibration of such a system. Two major issues are the identification of appropriate absorption lines and their dependence on the isotopic concentrations and composition. For this purpose the Tritium Absorption IR spectroscopy experiment has been set up as an extension of TRENTA. For calibration a Raman spectroscopy system is used. First measurements, with equilibrated mixtures of H
2
, D
2
and HD demonstrate that FTIR can be used for quantitative analysis of liquid hydrogen isotopologues and reveal a nonlinear dependence of the integrated absorbance from the D
2
concentration in the 2nd vibrational branch of D
2
FTIR spectra.
For the design of efficient hydrogen liquefaction plants and for the production of accurate ortho-para hydrogen samples, precise knowledge about the kinetics of ortho-para catalysts and accurate ...ortho-para monitoring is mandatory. Raman spectroscopy as a direct measurement of the ortho-para ratio is independent of other gas parameters, such as temperature, pressure, and flow rate and also undisturbed by impurities, such as nitrogen and oxygen in the gas. Therefore, Raman spectroscopy is a superior technique for ortho-para monitoring, com-pared to methods based on thermodynamic properties like heat conductivity. Within this work, an experimental proof of concept of a Raman based system to study ortho-para catalyst kinetics is shown.
•Raman based measuring system to study ortho-para cryo catalyst kinetics.•Raman method is independent of parameters, such as temperature, pressure, flow.•Experimental setup with a closed hydrogen loop and cyclical operation down to 77K.
The KATRIN experiment aims to measure the effective electron antineutrino mass
m
ν
¯
e
with a sensitivity of
0.2
eV
/
c
2
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
count
/
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.
The KATRIN experiment aims to determine the effective electron neutrino mass with a sensitivity of
0.2
eV/c
2
(%90 CL) by precision measurement of the shape of the tritium
β
-spectrum in the endpoint ...region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. A common background source in this setup is the decay of short-lived isotopes, such as
219
Rn
and
220
Rn
, in the spectrometer volume. Active and passive countermeasures have been implemented and tested at the KATRIN main spectrometer. One of these is the magnetic pulse method, which employs the existing air coil system to reduce the magnetic guiding field in the spectrometer on a short timescale in order to remove low- and high-energy stored electrons. Here we describe the working principle of this method and present results from commissioning measurements at the main spectrometer. Simulations with the particle-tracking software
Kassiopeia
were carried out to gain a detailed understanding of the electron storage conditions and removal processes.
Raman spectroscopy, a powerful method for the quantitative compositional analysis of molecular gases, e.g. mixtures of hydrogen isotopologues, is not able to detect monoatomic species like helium. ...This deficit can be overcome by using radioluminescence emission from helium atoms induced by β-electrons from tritium decay. We present theoretical considerations and combined Raman/radioluminescence spectra. Furthermore, we discuss the linearity of the method together with validation measurements for determining the pressure dependence. Finally, we conclude how this technique can be used for samples of helium with traces of tritium, and vice versa.
The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at − 18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise ...high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two 83mKr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN’s commissioning measurements in July 2017. The measured scale factor M=1972.449(10) of the high-voltage divider K35 is in agreement with the last PTB calibration 4 years ago. This result demonstrates the utility of the calibration method, as well as the long-term stability of the voltage divider.
Abstract The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at − 18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise ...high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two $$^{83{\mathrm{m}}}$$ 83m Kr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN’s commissioning measurements in July 2017. The measured scale factor $$M=1972.449(10)$$ M=1972.449(10) of the high-voltage divider K35 is in agreement with the last PTB calibration 4 years ago. This result demonstrates the utility of the calibration method, as well as the long-term stability of the voltage divider.
The KATRIN experiment aims to measure the effective electron antineutrino mass \(m_{\overline{\nu}_e}\) with a sensitivity of 0.2 eV/c\(^2\) 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 count/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.
In this work, we present the first spectroscopic measurements of conversion
electrons originating from the decay of metastable gaseous $^\mathrm{83m}$Kr
with the Karlsruhe Tritium Neutrino (KATRIN) ...experiment. The results obtained
in this calibration measurement represent a major commissioning milestone for
the upcoming direct neutrino mass measurement with KATRIN. The successful
campaign demonstrates the functionalities of the full KATRIN beamline. The
KATRIN main spectrometer's excellent energy resolution of ~ 1 eV made it
possible to determine the narrow K-32 and L$_3$-32 conversion electron line
widths with an unprecedented precision of ~ 1 %.
The KArlsruhe TRItium Neutrino (KATRIN) experiment aims to make a model-independent determination of the effective electron antineutrino mass with a sensitivity of 0.2 eV/c\(^{2}\). It investigates ...the kinematics of \(\beta\)-particles from tritium \(\beta\)-decay close to the endpoint of the energy spectrum. Because the KATRIN main spectrometer (MS) is located above ground, muon-induced backgrounds are of particular concern. Coincidence measurements with the MS and a scintillator-based muon detector system confirmed the model of secondary electron production by cosmic-ray muons inside the MS. Correlation measurements with the same setup showed that about \(12\%\) of secondary electrons emitted from the inner surface are induced by cosmic-ray muons, with approximately one secondary electron produced for every 17 muon crossings. However, the magnetic and electrostatic shielding of the MS is able to efficiently suppress these electrons, and we find that muons are responsible for less than \(17\%\) (\(90\%\) confidence level) of the overall MS background.
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