A high power liquid hydrogen target for parity violation experiments

Beise, E. J.; Beck, D.; Candell, E.; Carr, R.; Duncan, F.; Forest, T. A.; Korsch, W.; Mark, John W.; McKeown, R. D.; Mueller, B.; Pitt, M. L.; Wells, S. P.

doi:10.1016/0168-9002(96)00489-5

Cited by 23 publications

(8 citation statements)

References 6 publications

(5 reference statements)

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“…The liquid hydrogen target is 40 cm long, and is part of a high flow-rate recirculating liquid hydrogen system with a heat exchanger to remove the ϳ500 watts of heat deposited by the electron beam. Studies of the performance [9] of the target indicate that with 40 mA of beam the target can be maintained as a subcooled liquid and that density fluctuations are less than 0.1%. The fluctuations in the detected signal are then dominated by counting statistics of the scattered particles.…”

mentioning

confidence: 99%

Measurement of the Proton's Neutral Weak Magnetic Form Factor

Mueller¹,

Beck²,

Beise³

et al. 1997

Phys. Rev. Lett.

169

109

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We report the first measurement of the parity-violating asymmetry in elastic electron scattering from the proton. The asymmetry depends on the neutral weak magnetic form factor of the proton which contains new information on the contribution of strange quark-antiquark pairs to the magnetic moment of the proton. We obtain the value G Z M 0.34 6 0.09 6 0.04 6 0.05 n.m. at Q 2 0.1 ͑GeV͞c͒ 2 . [S0031-9007(97)03181-5] PACS numbers: 13.60. Fz, 11.30.Er, 13.40.Gp, 14.20.Dh The measurement of strange quark-antiquark (ss) effects in the nucleon offers a unique window to study the effects of the qq "sea" at low momentum transfers. This information is an important clue to the dynamical effects of QCD that are responsible for form factors in the nonperturbative regime, and may lead to new insight into the origins of these effects.It has been shown [1] that the neutral weak current can be used to determine the ss contributions to nucleon form factors. The magnetic moment is one important nucleon property that can be studied in this fashion. The neutral weak magnetic form factor of the proton can be measured in parity-violating electron scattering, [2], thus providing information on the ss content of the nucleon's magnetic moment. In this Letter, we report the first such measurement and obtain the first direct experimental data relevant to determination of the strange magnetic moment of the proton.To lowest order (tree-level), the neutral weak magnetic form factor of the proton G Z M can be related to nucleon electromagnetic form factors and a contribution from strange quarks: As mentioned above, the quantity G Z M for the proton can be measured via elastic parity-violating electron scattering at backward angles [2]. The difference in cross sections for right and left handed incident electrons arises from interference of the electromagnetic and neutral weak amplitudes, and so contains products of electromagnetic and neutral weak form factors. The expression for elastic scattering from the proton is given by

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mentioning

confidence: 99%

Measurement of the Proton's Neutral Weak Magnetic Form Factor

Mueller¹,

Beck²,

Beise³

et al. 1997

Phys. Rev. Lett.

169

109

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“…Hydrogen safety issues can trigger a broad variety of answers [8][9][10]. For instance, the NFPA panel is delegated to generate H 2 standards and create a Proposed Hydrogen Technology Correlating Committee.…”

Section: Electrical Component Solutionsmentioning

confidence: 99%

“…A continuous flow of 27 g/s, 14 K helium is necessary to cool the 25 liters of sub-cooled LH 2 flowing in a closed loop composed of a 6.9-liter absorber, a LH 2 pump, a He/H 2 counter-flow heat exchanger and a heater. Although a conceptual design for the forced-flow system was completed in 2002 [6][7] an alternative solution using the existing cryostat from the SAMPLE experiment is being considered [8]. Numerical simulations were necessary to size the cryo-system and to optimize the LH 2 flow hydro-dynamics [7] so that up to 300 W can be deposited by the dummy beam to the LH 2 absorber.…”

Section: A Future Continuous Helium Supplymentioning

confidence: 99%

“…The design of the different cryo-systems (forced-flow LH 2 absorber, KEK LH 2 absorber and superconducting solenoid magnet) utilizes the expertise of existing US hydrogen experiments [8][9] and Fermilab LH 2 target guidelines. Due to the presence of hydrogen in the experimental hall, all ignition sources must be rated Class I (areas with flammable vapors), Division 2 (hazard normally not present), group B (hazard is hydrogen) in accordance with the National Electrical Code (NEC).…”

Section: Electrical Component Solutionsmentioning

confidence: 99%

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Cryogenics for the MuCool Test Area (MTA)

Darve¹,

Norris²,

Pei³

2006

AIP Conference Proceedings

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Abstract. MuCool Test Area (MTA) is a complex of buildings at Fermi National Accelerator Laboratory, which are dedicated to operate components of a cooling cell to be used for Muon Collider and Neutrino Factory R&D. The long-term goal of this facility is to test ionization cooling principles by operating a 25-liter liquid hydrogen (LH 2 ) absorber embedded in a 5 Tesla superconducting solenoid magnet. The MTA solenoid magnet will be used with RF cavities exposed to a high intensity beam. Cryogens used at the MTA include LHe, LN 2 and LH 2 . The latter dictates stringent system design for hazardous locations. The cryogenic plant is a modified Tevatron refrigerator based on the Claude cycle. The implementation of an in-house refrigerator system and two 300 kilowatt screw compressors is under development. The helium refrigeration capacity is 500 W at 14 K. In addition the MTA solenoid magnet will be batch-filled with LHe every 2 days using the same cryo-plant. This paper reviews cryogenic systems used to support the Muon Collider and Neutrino Factory R&D programs and emphasizes the feasibility of handling cryogenic equipment at MTA in a safe manner.

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“…Therefore, the task of in-beam heat removal is to be solved. Recently, Experiments at the MIT-Bates accelerator [1,2], at the TJNAF [3], and at SLAC [4] have reported on their powerful targets. In this paper we present the target design and realization for the A4-experiment at the MAMI accelerator in Mainz [5,6,7,8,9].…”

Section: Introductionmentioning

confidence: 99%

A high power liquid hydrogen target for the Mainz A4 parity violation experiment

Altarev¹,

Schilling²,

Baunack³

et al. 2006

Nuclear Instruments and Methods in Physics Research Section A:

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We present a new powerful liquid hydrogen target developed for the precise study of parity violating electron scattering on hydrogen and deuterium. This target has been designed to have minimal target density fluctuations under the heat load of a 20µA CW 854.3 MeV electron beam without rastering the electron beam. The target cell has a wide aperture for scattered electrons and is axially symmetric around the beam axis. The construction is optimized to intensify heat exchange by a transverse turbulent mixing in the hydrogen stream, which is directed along the electron beam. The target is constructed as a closed loop circulating system cooled by a helium refrigerator. It is operated by a tangential mechanical pump with an optional natural convection mode. The cooling system supports up to 250 watts of the beam heating removal. Deeply subcooled liquid hydrogen is used for keeping the in-beam temperature below the boiling point. The target density fluctuations are found to be at the level 10 −3 at a beam current of 20 µA.

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A high power liquid hydrogen target for parity violation experiments

Cited by 23 publications

References 6 publications

Measurement of the Proton's Neutral Weak Magnetic Form Factor

Measurement of the Proton's Neutral Weak Magnetic Form Factor

Cryogenics for the MuCool Test Area (MTA)

A high power liquid hydrogen target for the Mainz A4 parity violation experiment

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