Florian Priester

Monitoring of tritium purity during long-term circulation in the KATRIN test experiment LOOPINO using Laser Raman Spectroscopy

Abstract The gas circulation loop LOOPINO has been set up and commissioned at Tritium Laboratory Karlsruhe (TLK) to perform Raman measurements of circulating tritium mixtures under conditions similar to the inner loop system of the neutrino-mass experiment KATRIN, which is currently under construction. A custom-made interface is used to connect the tritium containing measurement cell, located inside a glove box, with the Raman setup standing on the outside. A tritium sample (purity > 95 %, 20 kPa total pressure) was circulated in LOOPINO for more than three weeks with a total throughput of 770 g of tritium. Compositional changes in the sample and the formation of tritiated and deuterated methanes CT4-nXn (X=H,D; n=0,1) were observed. Both effects are caused by hydrogen isotope exchange reactions and gas-wall interactions, due to tritium β decay. A precision of 0.1 % was achieved for the monitoring of the T2 Q1-branch, which fulfils the requirements for the KATRIN experiment and demonstrates the feasibility of high-precision Raman measurements with tritium inside a glove box.

CAPER as Central and Crucial Facility to Support R&D with Tritium at TLK

Abstract The CAPER facility at TLK originally devoted to R&D on tokamak exhaust processing has been significantly upgraded over the last years. Beside new R&D on highly tritiated water, CAPER is presently largely used to support satellite experiments, mainly those dedicated to R&D on advanced analytics. Mutation from R&D to part of the TLK tritium infrastructure necessitated new features to be installed in order to facilitate and optimize tritiated mixtures preparation and sample filling, and to enable satellites experiments to discharge their waste gas to CAPER for clean-up. This paper presents recent CAPER mutations to become a central and key facility at TLK.

A New Device for Activity Measurement of Tritiated Water

Abstract This technical note describes advances in the activity measurement of tritiated water with the method of scintillation counting in a solid fibre. The device described can be installed inline thus enabling the monitoring of a process without the need for taking samples. Due to the low overall costs, the system can be installed at various positions in a larger plant adding additional safety and better control over the process. The current technical note on the TRAMPEL setup (TRitium Activity Monitoring with a PhotomultipliEr in Liquids) focuses on the updates and enhanced detection limits due to an updated readout and DAQ system. It is now possible to measure inline down to activity concentrations of 104 Bq/ml, which is roughly one order of magnitude lower than previously reported. A possible memory effect as well as the influence of the filling level was investigated. All measurements were performed with a standalone (non-inline) cell but can be applied for a flow-through application, too.

Status of the Karlsruhe Tritium Neutrino Mass Experiment KATRIN

Abstract Among the most important questions in fundamental physics and cosmology are the origin and the masses of fundamental particles, in particular the neutrino masses. KATRIN will allow a model-independent measurement of the neutrino mass scale with an expected sensitivity of 0.2 eV/c2 (90% CL). KATRIN will use a source of ultrapure molecular tritium and is currently being commissioned at KIT, thereby making use of the unique expertise of the Tritium Laboratory Karlsruhe. This paper presents the status of the KATRIN experiment, with the focus on the activity monitoring of the KATRIN tritium source.

Post service examination of turbomolecular pumps after stress testing with Kg-scale tritium throughput

Abstract Turbomolecular pumps (TMP) will be used with large amounts of tritium in future fusion machines like ITER, DEMO and in the KATRIN Experiment. In the work presented, a stress test of a Leybold® MAG W2800 with a tritium throughput of 1.1 kg over 384 days of operation was performed at TLK. After this, the pump was dismantled and the tritium uptake in several parts was determined. Especially the non-metallic parts of the pump absorb large amounts of tritium and are most likely responsible for the observed pollution of the process gas. The total tritium uptake of the TMP was estimated with 0.1-1.1 TBq. No radiation-induced damages were found on the inner parts of the pump. The TMP showed no signs of functional limitations during the 384 days of operation.