In modern particle and accelerator physics as well as in nuclear fusion experiments turbo-molecular pumps (TMP) are used in close proximity to super-conducting magnets. This can cause considerable ...heating of the fast moving rotor by eddy currents, which can ultimately lead to the destruction of the pump. Motivated by the KATRIN neutrino experiment, where TMPs are operated close to super-conducting magnets, a measurement programme has been elaborated to investigate the effect of magnetic fields on TMPs. An infra-red pyrometer has been used to measure the temperature of the revolving rotor. In addition the effect of different gas loads on the temperature was investigated. With these data a simplified model has been developed to predict the evolution of the rotor temperature over time, using easy to measure parameters. Here we introduce the new model and present first measurements and their application in predicting the rotor temperature in the pulsed field of a nuclear fusion experiment.
► We investigated turbo-molecular pumps in strong magnetic fields. ► An experimental setup measures the rotor temperature for different fields and gas flows. ► An empirical model with 5 easy to measure parameters describe the rotor temperature. ► The model can predict the temperature when designing a vacuum system. ► The rotor temperature in a pulsed field of a fusion reactor is calculated.
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 Formula omittedKr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN's commissioning measurements in July 2017. The measured scale factor Formula omitted 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 TRAP experiment (TRitium Argon frost Pump) has been built at the Tritium Laboratory Karlsruhe (TLK) as a test rig for the Cryogenic Pumping Section (CPS) of the KArlsruhe TRltium Neutrino ...Experiment (KATRIN). TRAP employs a heterogeneous layer of pre-condensed argon to adsorb hydrogen isotopes at - 4.2 K. This paper presents results obtained in the first three tritium experiments with TRAP.
The design of a tritium processing loop for KATRIN tritium source and results of test set-up operation are presented. The constant source intensity is supported by high purity ( > 95% of tritium) of ...tritium circulated through the source with 4.8.10 g/s rate. The possibility of source parameters stabilization was verified with test facility 'TILO' which was built for this purpose. The long term (30 days) deuterium circulation with flow rate 0.2 Pa m3/s shows that using of standard high accuracy pressure sensors from MKS and NI control electronics allows to stabilize the flow rate in the system with 0.1% accuracy. The reliability of process equipment was tested as well during about 3000 h of TILO operation.
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/c2. It investigates the ...kinematics of β-particles from tritium β-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.
The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to determine the effective electron (anti)-neutrino mass with a sensitivity of 0.2eV/c \(^2\) by precisely measuring the endpoint region of the ...tritium \(\beta \) -decay spectrum. It uses a tandem of electrostatic spectrometers working as magnetic adiabatic collimation combined with an electrostatic (MAC-E) filters. In the space between the pre-spectrometer and the main spectrometer, creating a Penning trap is unavoidable when the superconducting magnet between the two spectrometers, biased at their respective nominal potentials, is energized. The electrons accumulated in this trap can lead to discharges, which create additional background electrons and endanger the spectrometer and detector section downstream. To counteract this problem, “electron catchers” were installed in the beamline inside the magnet bore between the two spectrometers. These catchers can be moved across the magnetic-flux tube and intercept on a sub-ms time scale the stored electrons along their magnetron motion paths. In this paper, we report on the design and the successful commissioning of the electron catchers and present results on their efficiency in reducing the experimental background.
The KATRIN experiment aims to determine the effective electron neutrino mass with a sensitivity of 0.2eV/c2 (90\% C.L.) by precision measurement of the shape of the tritium beta-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 219Rn and 220Rn, 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.
TRAP—a cryo-pump for pumping tritium on pre-condensed argon Kazachenko, O.; Bornschein, B.; Bornschein, L. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2008, Letnik:
587, Številka:
1
Journal Article
Recenzirano
The TRitium Argon frost Pump experiment (TRAP) has been built at the Tritium Laboratory Karlsruhe (TLK) as a test rig for the Cryogenic Pumping Section (CPS) of the KArlsruhe TRItium Neutrino ...Experiment (KATRIN). TRAP employs a heterogeneous layer of pre-condensed argon to adsorb hydrogen isotopes at
∼
4.2
K
. This article covers the technical setup of the TRAP experiment and presents first results obtained in a commissioning run with deuterium.
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.
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