arXiv subjects

Robin Größle

Publications and source records attributed to Robin Größle.

6 recordsLinked to original sources

arXiv2026

Gaseous Tritium Activity Monitoring with Scintillators (GaTAMoS)

We present a novel device for the inline activity monitoring of gaseous tritium, named Gaseous Tritium Activity Monitoring with Scintillators (GaTAMOS). Unlike established methods that often rely on liquid scintillation or plastic scintillators with limited chemical resistance, this system utilises a chemically inert, inorganic Terbium-activated Gadolinium Oxysulfide (Gd2O2S:Tb) ceramic. A specialised soldering technique was developed to join the ceramic scintillator to a stainless-steel flange, achieving a vacuum-tight seal fully compatible with high-purity tritium applications. The device was characterised using pure tritium gas, demonstrating a linear response and high sensitivity across a dynamic range from < 1 kBq to >10 GBq. A key advantage of the ceramic material over organic alternatives is its high tolerance to aggressive cleaning agents. We demonstrate that the inevitable tritium memory effect can be significantly mitigated by flushing the cell with ethanol, removing >95% of residual contamination within minutes. The proposed system offers a compact, robust, and cost-effective alternative to ionisation chambers or BIXS systems for process monitoring in tritium handling facilities.

physics.ins-det↗

arXiv2025

Tritium accumulation and ozone decontamination of tungsten and beryllium

Tritium adsorption on surfaces creates a variety of issues, ranging from the fields of fusion applications to small and large-scale laboratory experiments using tritium. The extent to which tritium accumulates on surfaces is generally material-dependent and must be determined through experiments. Additionally, this surface contamination necessitates the implementation of appropriate decontamination procedures, preferably in-situ. A suitable method could be exposure to ozone during UV irradiation. However, it is currently not known if both components are necessary for the decontamination. At Tritium Laboratory Karlsruhe, both questions on contamination and decontamination can be addressed using a single experimental setup. With this, it is possible to expose solid samples to gaseous tritium to measure the temporal activity evolution. Furthermore, the system can be filled with dry air, and dry air containing ozone to explore their decontamination effect. Both measurement modes were applied to beryllium and tungsten samples, which were chosen for their relevance in fusion. The beryllium surface was observed to accumulate tritium more than four times faster than tungsten when exposed to gaseous tritium. Concerning the decontamination, without simultaneous UV irradiation, exposure to ozone did not have any distinct effect on the surface activity compared to simply using dry air. This leads to the conclusion that UV illumination of the surfaces is required to achieve a significant decontamination factor.

cond-mat.mtrl-sci↗

arXiv2025

First results of the Tritium Absorption InfraRed Spectroscopy (T2ApIR) experiment

The literature on experimentally verified material properties of tritium is sparse but information about this is crucial in fusion for pellet production (Magnetic Confined Fusion), target fueling (Inertial Confined Fusion), cryogenic distillation, as well as in astroparticle physics for neutrino experiments, and search for rare physics. To improve on this, the T$_2$ApIR experiment has been designed and built at the Tritium Laboratory Karlsruhe (TLK), and is in its scientific commissioning phase. The main focus of this experiment is to enable the investigation of the properties of all six hydrogen isotopologues and their mixtures in the gaseous, liquid, and solid phase, as well as the dynamics of their phase changes. In addition, mixtures with noble gases such as xenon and neon can be investigated. This is achieved using a cryogenic setup capable of reaching less than 10 in a measurement cell that allows optical access for infrared absorption spectroscopy, Raman spectroscopy and a polariscope setup, as well as temperature and pressure measurement.

physics.ins-det↗

arXiv2025

Commissioning of an experiment for thermodynamic and spectroscopic studies of hydrogen isotopologues at cryogenic conditions

To study thermodynamic properties and dynamic phase space behavior of hydrogen isotopologues (Q$_2$) at cryogenic temperatures and at high density, the Tritium Absorption InfraRed Spectroscopy 2 (T$_2$ApIR) experiment has been set up and commissioned at Tritium Laboratory Karlsruhe (TLK). In the frame of the experiment, Q$_2$ behavior in different phases, ortho/para states, temperatures (10 K - 300 K) and pressures (up to 2.5 bar a) will be investigated with optical methods, infrared and Raman spectroscopy. The facility consists of a fully tritium compatible cryostat, which includes an optical cell, ortho/para converter and windows for optical and spectroscopic studies. The cryostat can be cooled below the H$_2$ triple point by a two-stage cryocooler and contains openings in the cryogenic shielding for the optical access. The challenge of combining these scientific requirements in a design with high amounts of tritium (14 g), in a limited space, all while maintaining the TLK safety philosophy was solved by the presented design. The experiment is ready to be fully integrated into the TLK closed loop tritium infrastructure. This contribution reports a comprehensive overview of the commissioning phase of the experimental facility and the results of the first commissioning experiments, including cryogenic performance tests, commissioning experiments with non-radioactive gases, and tests of the analytical instruments.

cond-mat.stat-mech↗

arXiv2022

ViMA -- the spinning rotor gauge to measure the viscosity of tritium between 77 and 300 K

Experimental values for the viscosity of the radioactive hydrogen isotope tritium (T$_2$) are currently unavailable in literature. The value of this material property over a wide temperature range is of interest for applications in the field of fusion, neutrino physics, as well as to test ab initio calculations. As a radioactive gas, tritium requires careful experiment design to ensure safe and environmental contamination free measurements. In this contribution, we present a spinning rotor gauge based, tritium compatible design of a gas viscosity measurement apparatus (ViMA) capable of covering the temperature range from 80 K to 300 K.

physics.ins-det↗

arXiv2022

Viscosity measurements of gaseous H2 between 200 K to 300 K with a spinning rotor gauge

Experimental values for the viscosity of the radioactive hydrogen isotopologue tritium are still unknown in literature. Existing values from ab initio calculations disregard quantum mechanic effects and are therefore only good approximations for room temperature and above. To fill in these missing experimental values, a measurement setup has been designed, to measure the viscosity of gaseous hydrogen and its isotopologues (H$_2$, HD, HT, D$_2$, DT, T$_2$) at cryogenic temperatures. In this paper, the first results with this Cryogenic Viscosity Measurement Apparatus (Cryo-ViMA) of the viscosity of gaseous hydrogen between 200 K to 300 K are presented.

physics.ins-det↗