Investigation of turbo-molecular pumps in strong magnetic fields

Wolf, J.; Bornschein, B.; Drexlin, G.; Gehring, R.; Größle, Robin; Horn, Susanne; Kernert, N.; Riegel, Sebastian; Neeb, R.; Wagner, A. James

doi:10.1016/j.vacuum.2011.07.063

Cited by 18 publications

(10 citation statements)

References 10 publications

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“…Specifically, the vacuum system of the spectrometer section consists of six TMPs [62] installed in pairs at the three pump ports at the detector-facing end of the main spectrometer and two smaller TMPs at the pre-spectrometer pump ports. The pump ports in the main spectrometer (pre-spectrometer) are additionally equipped with 3000 m (180 m) of NEG strips [63,64].…”

Section: The Vacuum System Of the Katrin Spectrometer Sectionmentioning

confidence: 99%

Background due to stored electrons following nuclear decays in the KATRIN spectrometers and its impact on the neutrino mass sensitivity

Mertens

Drexlin

Fränkle

et al. 2013

Astroparticle Physics

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The KATRIN experiment is designed to measure the absolute neutrino mass scale with a sensitivity of 200 meV at 90% C.L. by high resolution tritium β-spectroscopy. A low background level of 10 mHz at the β-decay endpoint is required in order to achieve the design sensitivity. In this paper we discuss a novel background source arising from magnetically trapped keV electrons in electrostatic retarding spectrometers. The main sources of these electrons are α-decays of the radon isotopes 219,220 Rn as well as β-decays of tritium in the volume of the spectrometers. We characterize the expected background signal by extensive MC simulations and investigate the impact on the KATRIN neutrino mass sensitivity. From these results we refine design parameters for the spectrometer vacuum system and propose active background reduction methods to meet the stringent design limits for the overall background rate.

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Section: The Vacuum System Of the Katrin Spectrometer Sectionmentioning

confidence: 99%

Background due to stored electrons following nuclear decays in the KATRIN spectrometers and its impact on the neutrino mass sensitivity

Mertens

Drexlin

Fränkle

et al. 2013

Astroparticle Physics

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“…R(60 d) > 10 12 . In this case a linear interpolation between the first non zero bin and the origin (where the tritium flow is expected to be zero) is applied.…”

Section: Reduction Factor Calculationmentioning

confidence: 97%

“…The superconducting magnets surrounding the beamline provide a guiding field of up to 5.5 T [11]. A passive magnetic shield encases each TMP to prevent eddy currents from heating up, and possible crashing, of the fast-moving rotors [12].…”

Section: Vacuum Systemmentioning

confidence: 99%

Time-dependent simulation of the flow reduction of D2 and T2 in the KATRIN experiment

Friedel

Röttele

Schimpf

et al. 2019

Vacuum

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The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to measure the effective electron anti-neutrino mass with an unprecedented sensitivity of 0.2 eV/c 2 , using β-electrons from tritium decay. Superconducting magnets will guide the electrons through a vacuum beam-line from the windowless gaseous tritium source through differential and cryogenic pumping sections to a high resolution spectrometer. At the same time tritium gas has to be prevented from entering the spectrometer. Therefore, the pumping sections have to reduce the tritium flow by at least 14 orders of magnitude. This paper describes various simulation methods in the molecular flow regime used to determine the expected gas flow reduction in the pumping sections for deuterium (commissioning runs) and for radioactive tritium. Simulations with MolFlow+ and with an analytical model are compared with each other, and with the stringent requirements of the KATRIN experiment.

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“…Turbopumps are sensitive to dust (because of the high rotor speeds), vibrations and sudden vacuum breaks (magnetic bearing with small gaps between rotor and stator), changing magnetic fields (mainly problems of controlling the magnetic bearings and thermal problems due to eddy currents in the rotor) and high gas loads (rotor heat can only be removed by thermal radiation what leads to high rotor temperatures). In order to reduce the eddy heating effect of the rotor which already becomes inacceptable at field stremgths of the order of some mT [17], ceramic rotors have been developed in the 90s, initiated from the Japanese Fusion Programme, but the achieved performance was not convincing [18]. A 2 m³/s turbopump that had been specially developed for fusion applications with a sealed bearing set and other material changes to make it tritium compatible [19], has been used at JET, but the tritium-compatibility is still questionable and various on-machine failures have been experienced.…”

Section: ) Turbomolecular Pumpsmentioning

confidence: 99%

Exhaust pumping of DT fusion devices: Current state-of-the-art and a potential roadmap to a fusion power plant

Day

Giegerich

2013

2013 IEEE 25th Symposium on Fusion Engineering (SOFE)

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The main functions of the exhaust pumping system of a DT fusion device are to pump out the helium ash and to control the divertor neutral gas density. This requires the handling of large gas throughputs at high pumping speeds (but at relatively moderate vacua). The pumped exhaust gas is then usually transported to the tritium plant for cleaning, which involves impurity removal and separation of the pure hydrogenic species for re-injection as fuel.In view of a fusion power plant, a systematic technical review of primary and roughing pump technologies is conducted in order to identify potential exhaust pumping concepts which eliminate some of the disadvantages that eventually result from simple scale-up of the ITER solutions that are based on batchwise operating cryogenic pumps. This paper also illustrates the methodology applied to come to unbiased results and describes the final configuration which is based on a vapor diffusion pump as primary pump together with a metal foil pump for hydrogen separation, and a liquid metal ring pump as roughing pump. All pumps are working continuously and do not require cryogenic temperatures.The new concept will reduce the tritium inventories of a power plant, firstly because of the continuous pumping characteristics of the pumps involved, and secondly because the metal foil pump allows for internal recycling of the unburnt fuel species directly from the divertor to the fuelling systems, bypassing the tritium plant.

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Investigation of turbo-molecular pumps in strong magnetic fields

Cited by 18 publications

References 10 publications

Background due to stored electrons following nuclear decays in the KATRIN spectrometers and its impact on the neutrino mass sensitivity

Background due to stored electrons following nuclear decays in the KATRIN spectrometers and its impact on the neutrino mass sensitivity

Time-dependent simulation of the flow reduction of D2 and T2 in the KATRIN experiment

Exhaust pumping of DT fusion devices: Current state-of-the-art and a potential roadmap to a fusion power plant

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