An atomic beam polarimeter to measure the nuclear polarization in the HERMES gaseous polarized hydrogen and deuterium target

Baumgarten, C.; Braun, B.; Court, G.R.; Ciullo, G.; Ferretti, Paola; Golendukhin, A.; Graw, G.; Haeberli, W.; Henoch, M.; Hertenberger, R.; Koch, Norbert; Kolster, H.; Lenisa, P.; Nass, A.; Pod'yachev, S.P.; Reggiani, D.; Rith, Klaus; Simani, M. C.; Steffens, E.; Stewart, J.; Wise, T.

doi:10.1016/s0168-9002(01)01738-7

Cited by 46 publications

(28 citation statements)

References 9 publications

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“…3. The two main components of the experimental apparatus used for the measurement are the polarized hydrogen gas target [9,10] making use of a storage cell, installed at the PAX interaction point, and the beam polarimeter. Beam polarimetry has been accomplished by detecting elastically scattered protons off a deuterium cluster target [11] by means of two silicon tracking telescopes [12].…”

Section: Methodsmentioning

confidence: 99%

Polarization of a stored beam by spin filtering

Weidemann

2014

EPJ Web of Conferences

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Abstract. In 2011 the PAX Collaboration has performed a successful spin-filtering test using protons at T p = 49.3 MeV at the COSY ring, which confirms that spin filtering is a viable method to polarize a stored beam and that the present interpretation of the mechanism in terms of the proton-proton interaction is correct. The equipment and the procedures to produce stored polarized beams was successfully commissioned and are established. The outcome of the experiment is of utmost importance in view of the possible application of the method to polarize a beam of stored antiprotons.

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Section: Methodsmentioning

confidence: 99%

Polarization of a stored beam by spin filtering

Weidemann

2014

EPJ Web of Conferences

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“…The target vacuum chamber containing the storage cell is surrounded by the external target magnet which provides a strong holding field to define the direction of polarization and to decouple the nuclear and electron spins. The nuclear polarization and the atomic fraction of the target gas are determined analyzing a sample beam diffusing through a side tube from the center of the cell to the Breit-Rabi polarimeter (BRP) [27] and to the target gas analyzer (TGA) [28], respectively, as it will be described in the next section.…”

Section: The Hermes Targetmentioning

confidence: 99%

“…The nuclear and electronic polarizations of the atoms in a given magnetic field are linear functions of the hyperfine state population numbers n i and are calculated as described in reference [27].…”

Section: Breit-rabi Polarimeter and Target Gas Analyzermentioning

confidence: 99%

First measurement of the hydrogen spin-exchange collision cross-section in the low temperature region

Baumgarten¹,

Braun

Capiluppi

et al. 2008

Eur. Phys. J. D

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Abstract. The spin-exchange collision cross-section for hydrogen atoms has been measured for the first time in the low temperature range 40-100 K by using the polarized hydrogen gas target of the HERMES experiment at DESY (Hamburg, Germany). The results agree with a previous measurement in the overlapping temperature region 80-100 K, while seem to hint an increasing behaviour with temperature in the region 50-80 K.

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“…A small sample of target gas enters the sampling tube and is subsequently analyzed by the BRP or the target gas analyzer (TGA). The BRP [80] essentially works in reverse to the ABS. High frequency transitions and a sextupole system are used to select a particular hyperfine state.…”

Section: The Polarized Targetmentioning

confidence: 99%

Polarized Parton Distributions Measured at the HERMES Experiment

Wendland

2004

AIP Conference Proceedings

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The HERMES experiment at DESY, Germany was designed to carry out precision measurements of the proton spin structure using polarized deep-inelastic scattering. The experiment utilizes the ¾ Î electron or positron beam of the HERA accelerator which is longitudinally polarized at HERMES, in combination with a polarized internal gas target. For this work, data on longitudinally polarized hydrogen and deuterium targets were used to determine cross section asymmetries with respect to the alignment of the target and beam polarizations. Inclusive asymmetries on the proton and the deuteron, where only the scattered electron/positron is detected, were measured with high precision. In semi-inclusive deep-inelastic scattering, at least one final-state hadron is detected in coincidence. Semi-inclusive asymmetries of pions on the proton and pion and kaon asymmetries on the deuteron were measured for the first time by the HERMES collaboration. The measured asymmetries include detector effects and effects of higher-order processes in quantum electrodynamics.A new unfolding procedure that takes into account the correlations between kinematic bins was implemented to correct for these effects.The polarized parton densities of the up, down, and sea flavours were obtained from the unfolded inclusive and semi-inclusive asymmetries in a probabilistic analysis based on leading-order quantum chromodynamics. In the case of the up quark and the down quark, the polarized densities were determined to be positive and negative, respectively. The polarized densities of the sea flavours, decomposed for the first time into the densities of the anti-up, anti-down, and strange quarks, were found to be compatible with zero. Moments of the polarized parton densities were computed. TheBjørken sum rule was verified and the total spin carried by the quark spins was determined to bé ¿ ¼ ¦ ¼µ ±. This latter result is larger than earlier measurements but still smaller than ¼ ± predicted in relativistic models of the proton.iii iv ABSTRACT AcknowledgementsFirst of all I would like to thank my adviser, Dr. Michel Vetterli, for providing the opportunity to conduct research on the nucleon spin structure. His support towards the completion of this work was indispensable. I would also like to thank the members of the ¡Õ-group, notably Thore Lindemann and Marc Beckmann, whose collaboration was invaluable.My thanks go to Elke Aschenauer for her tremendous efforts in running the experiment and in contributing to the analysis. I am indebted to Naomi Makins for the numerous discussions we had.

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An atomic beam polarimeter to measure the nuclear polarization in the HERMES gaseous polarized hydrogen and deuterium target

Cited by 46 publications

References 9 publications

Polarization of a stored beam by spin filtering

Polarization of a stored beam by spin filtering

First measurement of the hydrogen spin-exchange collision cross-section in the low temperature region

Polarized Parton Distributions Measured at the HERMES Experiment

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