New improvements leading to higher polarization frozen spin HD targets at the LEGS facility

Wei, X.; Bade, C.; Caracappa, A.; Kageya, T.; Lincoln, F.; Lowry, M.; Mahon, J.; Sandorfi, A. M.; Thorn, C.; Whisnant, C. S.

doi:10.1016/j.nima.2004.03.168

Cited by 10 publications

(8 citation statements)

References 12 publications

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“…The HD gas contains trace amounts of H 2 and D 2 that are necessary for the polarization process [9]. Once the target cell 1 The chemical composition for polychlorotrifluoroethylene is C 2 ClF 3 .…”

Section: Production Of a Hd Targetmentioning

confidence: 99%

“…These polarize rapidly and transfer their polarization to HD. As the metastable impurities decay away (with relaxation times of 6 and 18 days for H 2 and D 2 , respectively), the solid HD reaches high polarization and a frozen-spin state [9]. A target is nominally held under these conditions for approximately two to three months as the spins of the H and D decouple from the HD lattice.…”

Section: Polarizing the Hd Targetmentioning

confidence: 99%

“…The core design of the present TC was originally developed at BNL for handling frozen-spin HD targets during experiments at the Laser-Electron-Gamma-Source (LEGS) [5,9]. The overall dimensions of the TC were constrained by the geometry of the target cell, the dimensions of the cryostats used for production and polarization, and the requirement of maintaining target polarization during transport between cryostats.…”

Section: Design and Construction Featuresmentioning

confidence: 99%

“…Because of the significantly shorter spin relaxation times under the TC conditions, the time elapsed in each TC transfer must be minimized. Earlier generations of TCs used with HD targets had transfer success rates between 65% and 75% [7,8,9]. Such efficiencies result in an overall success rate of less than 25% for five transfers, (0.75) 5 , which makes the running of a major experiment difficult.…”

Section: Design and Construction Featuresmentioning

confidence: 99%

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A portable cryostat for the cold transfer of polarized solid HD targets: HDice-I

Bass

Bade

Blecher

et al. 2014

Nuclear Instruments and Methods in Physics Research Section A:

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A device has been developed with moveable liquid nitrogen and liquid helium volumes that is capable of reaching over two meters into the coldest regions of a cryostat or dilution refrigerator and reliably extracting or installing a target of solid, polarized hydrogen deuteride (HD). This Transfer Cryostat incorporates a cylindrical neodymium rare-earth magnet that is configured as a Halbach dipole, which is maintained at 77 K and produces a 0.1 T field around the HD target. Multiple layers provide a hermetic 77 K-shield as the device is used to maintain a target at 2 K during a transfer between cryostats. Tests with frozen-spin HD show negligible polarization loss for either H or D over typical transfer periods. Multiple target transfers with this apparatus have shown an overall reliability of about 95% per transfer, which is a significant improvement over earlier versions of the device.

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Section: Production Of a Hd Targetmentioning

confidence: 99%

Section: Polarizing the Hd Targetmentioning

confidence: 99%

Section: Design and Construction Featuresmentioning

confidence: 99%

Section: Design and Construction Featuresmentioning

confidence: 99%

See 2 more Smart Citations

A portable cryostat for the cold transfer of polarized solid HD targets: HDice-I

Bass

Bade

Blecher

et al. 2014

Nuclear Instruments and Methods in Physics Research Section A:

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“…Discussions of the earlier versions may be found in refs. [5,6]. A third paper is in preparation which will deal with the NMR measurement and RF manipulation of the polarization and with the polarization lifetime dependences on temperature, field and concentrations of metastable impurities.…”

Section: Introductionmentioning

confidence: 99%

A cryostat to hold frozen-spin polarized HD targets in CLAS: HDice-II

Lowry

Bass

D’Angelo

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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The design, fabrication, operation, and performance of a He-3/4 dilution refrigerator and superconducting magnet system for holding a frozen-spin polarized hydrogen deuteride target in the Jefferson Laboratory CLAS detector during photon beam running is reported. The device operates both vertically (for target loading) and horizontally (for target bombardment). The device proves capable of maintaining a base temperature of 50 mK and a holding field of 1 T for extended periods. These characteristics enabled multi-month polarization lifetimes for frozen spin HD targets having proton polarization of up to 50% and deuteron up to 27%. (C) 2016 Elsevier B.V. All rights reserved

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Development of portable NMR polarimeter system for polarized HD target

Ohta

Fujiwara

Fukuda

et al. 2011

Nuclear Instruments and Methods in Physics Research Section A:

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A portable NMR polarimeter system has been developed to measure the polarization of a polarized Hydrogen-Deuteride (HD) target for hadron photoproduction experiments at SPring-8. The polarized HD target is produced at the Research Center for Nuclear Physics (RCNP), Osaka university and is transported to SPring-8. The HD polarization should be monitored at both places. We have constructed the portable NMR polarimeter system by replacing the devices in the conventional system with the software system with PCI eXtensions for Instrumentation (PXI). The weight of the NMR system is downsized from 80 kg to 7 kg, and the cost is reduced to 25%. We check the performance of the portable NMR polarimeter system. The signal-to-noise (S /N) ratio of the NMR signal for the portable system is about 50% of that for the conventional NMR system. This performance of the portable NMR system is proved to be compatible with the conventional NMR system for the polarization measurement.

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New improvements leading to higher polarization frozen spin HD targets at the LEGS facility

Cited by 10 publications

References 12 publications

A portable cryostat for the cold transfer of polarized solid HD targets: HDice-I

A portable cryostat for the cold transfer of polarized solid HD targets: HDice-I

A cryostat to hold frozen-spin polarized HD targets in CLAS: HDice-II

Development of portable NMR polarimeter system for polarized HD target

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