Undulators are X-ray sources which are widely used in synchrotron storage rings and free-electron laser (FEL) facilities. As the development of future light sources envisages smaller and more compact ...undulators, it is necessary to construct small-scale high-field undulators with short period lengths <inline-formula><tex-math notation="LaTeX">\lambda \,< </tex-math></inline-formula> 10 mm and narrow magnetic gaps <inline-formula><tex-math notation="LaTeX">d_\text{mag} < </tex-math></inline-formula> 4 mm. Therefore, high-temperature superconducting (HTS) tapes are a promising candidate, since they offer a high critical current density at higher temperatures. Instead of the commonly used wounded coils of low-temperature superconducting (LTS) wires, such as NbTi, to generate the alternating magnetic dipole field, a meandering pattern is structured on the surface of the HTS tape with ps laser pulses to provide a sinusoidal current path through the tape, see Fig. <xref ref-type="fig" rid="fig1">1 . This technique leads to a precise structure and at the same time prevents damage to the superconducting layer due to overheating. A new concept has been developed and improved at KIT. The new concept involves two opposing stacks of 30 laser-structured HTS tapes. The ends of each tape are soldered and connected to the tape above, resulting in an accordion-like arrangement, see Figs. <xref ref-type="fig" rid="fig2">2 and <xref ref-type="fig" rid="fig3">3 . This paper presents the general design and the preparation of the stacks of the compact SCU, followed by the results of a Biot-Savart magnetic field simulation. The magnetic field measurement setup and a first current carrying test of the two coils are included.
•The permeances of H2, D2 and He exhibit a transition in the transport around 360 K.•The H2/He and D2/He permselectivities exceed their Knudsen selectivities.•The H2/D2 permeances ratio is close to ...the Knudsen selectivity.•The permeance of the hydrogen isotopologue with molecular weight M depends on M.•Permeances and selectivities in relation to He are presented for HD, HT, DT, T2.
In future fusion power plants, the tritium (T) breeding inside the reactor is a key aspect to ensure the so-called tritium self-sufficiency. The continuous availability of the fuel for further fusion reactions requires the continuous separation of small molecules such as hydrogen isotopologues (e.g., HT) from helium. Pressure-driven separation with membranes is a promising method to fulfill these requirements, especially if molecular-sieving membranes are available to separate these gas species. In this work, the single gas permeances of He, H2 and D2 were measured with a MFI-ZSM-5 zeolite-type tubular membrane. These experiments were performed in the membrane’s temperature range: 298–398K. At these temperatures, a transition in the transport regime was observed at 360K, which is attributed to the transition from surface-diffusion dominant to gas-translational diffusion dominant. Using the measured permeances, the permselectivities for H2/He and D2/He were calculated. In the temperature range tested, the permselectivities exceed the Knudsen selectivity, indicating that the membrane is of rather high-quality. Instead, the H2/D2 permeances ratio was around the Knudsen ratio (i.e., ∼1.41). Moreover, the permeances of the binary mixture H2/D2, at the whole concentration range, were also measured at 298K to study the isotopic effects on the transport through the MFI-ZSM-5 membrane. We found that the mixed gas behaves macroscopically as a hydrogen isotopologue molecule, and its permeance falls with Meff-0.5, where Meff is the effective mass of the mixture determined by the concentrations of H2 and D2. Using this result, the Q2 permeances and the Q2/He permselectivities (where Q = H, D, T) for the other hydrogen isotopologues (i.e., HD, HT, DT and T2) were also calculated.
Free electron laser (FEL) facilities provide broadly tunable and highly coherent photon beams. These machines still have an unexplored potential and development. The XLS-CompactLight design aims at a ...flexible hard plus soft X-ray FEL facility exploiting the latest concepts in terms of short period magnetic undulators, paving the road towards more compact photon sources.
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.
In a fusion reactor, tritium will be continuously produced in the breeding blanket and a dedicated tritium extraction and removal system (TERS) is used to recover the newly bred tritium. In the TERS ...for the solid blanket, zeolite membranes are proposed to be used to pre-concentrate HT/H2 in He before Pd/Ag membranes. Therefore, permeation experiments were carried out using two experimental facilities to determine the permeances of all hydrogen isotopologues (Q2 = H2, HD, D2, HT, DT, T2) through MFI-ZSM-5 membranes. This study aimed at investigating the existence of isotopic effects on the Q2 permeation and hence on the separation of Q2 from He. The results exhibit a strong dependency of the permeance with the mass of the isotopologue: the selectivity decreases from around 1.8 for H2/He to 1.3 for D2/He down to 1.1 for T2/He. This phenomenon is attributed to the existence of defects in the zeolite structure through which the molecules permeate according to Knudsen diffusion. These results were observed for inactive and active Q2 mixtures and no other effects related to the dipole moment of the asymmetric isotopologues (HD, HT, DT) or tritium decay were observed. Moreover, these results were obtained for three MFI-ZSM-5 membranes, showing a high reproducibility. Our results demonstrate that the pre-concentration of Q2 in He with MFI-ZSM-5 membranes appears to be challenging in the scope of the TERS.
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•Permeation of hydrogen through MFI membranes is dependent on the isotopologues mass.•Isotopic effect due to the existence of defects in the zeolite layer.•Separation of Q2/He is highest for H2 and lowest for T2.•MFI membranes exhibit low separation performances for the tritium extraction system.
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 Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to measure a high-precision integral spectrum of the endpoint region of T2 beta decay, with the primary goal of probing the absolute ...mass scale of the neutrino. After a first tritium commissioning campaign in 2018, the experiment has been regularly running since 2019, and in its first two measurement campaigns has already achieved a sub-eV sensitivity. After 1000 days of data-taking, KATRIN's design sensitivity is 0.2 eV at the 90% confidence level. In this white paper we describe the current status of KATRIN; explore prospects for measuring the neutrino mass and other physics observables, including sterile neutrinos and other beyond-Standard-Model hypotheses; and discuss research-and-development projects that may further improve the KATRIN sensitivity.
In this work we present a keV-scale sterile-neutrino search with the first
tritium data of the KATRIN experiment, acquired in the commissioning run in
2018. KATRIN performs a spectroscopic ...measurement of the tritium $\beta$-decay
spectrum with the main goal of directly determining the effective electron
anti-neutrino mass. During this commissioning phase a lower tritium activity
facilitated the search for sterile neutrinos with a mass of up to $1.6\,
\mathrm{keV}$. We do not find a signal and set an exclusion limit on the
sterile-to-active mixing amplitude of down to $\sin^2\theta < 5\cdot10^{-4}$
($95\,\%$ C.L.), improving current laboratory-based bounds in the
sterile-neutrino mass range between 0.1 and $1.0\, \mathrm{keV}$.
Some extensions of the Standard Model of Particle Physics allow for Lorentz invariance and Charge-Parity-Time (CPT)-invariance violations. In the neutrino sector strong constraints have been set by ...neutrino-oscillation and time-of-flight experiments. However, some Lorentz-invariance-violating parameters are not accessible via these probes. In this work, we focus on the parameters \((a_{\text{of}}^{(3)})_{00}\), \((a_{\text{of}}^{(3)})_{10}\) and \((a_{\text{of}}^{(3)})_{11}\) which would manifest themselves in a non-isotropic beta-decaying source as a sidereal oscillation and an overall shift of the spectral endpoint. Based on the data of the first scientific run of the KATRIN experiment, we set the first limit on \(\left|(a_{\text{of}}^{(3)})_{11}\right|\) of \(< 3.7\cdot10^{-6}\) GeV at 90\% confidence level. Moreover, we derive new constraints on \((a_{\text{of}}^{(3)})_{00}\) and \((a_{\text{of}}^{(3)})_{10}\).
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