Thermomechanical design of a static gas target for electron accelerators

A system of modular sealed gas target cells has been developed for use in electron scattering experiments at the Thomas Jefferson National Accelerator Facility (Jefferson Lab). This system was initially developed to complete the MARATHON experiment which required, among other species, tritium as a target material. Thus far, the cells have been loaded with the gas species 3 H, 3 He, 2 H, 1 H and 40 Ar and operated in nominal beam currents of up to 22.5 µA in Jefferson Lab's Hall A. While the gas density of the cells at the time of loading is known, the density of each gas varies uniquely when heated by the electron beam. To extract experimental cross sections using these cells, density dependence on beam current of each target fluid must be determined. In this study, data from measurements with several beam currents within the range of 2.5 to 22.5 µA on each target fluid are presented. Additionally, expressions for the beam current dependent fluid density of each target are developed.

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“…This design is similar to the design proposed in Ref. [10] with engineering details for the construction and loading of these cell in Ref. [11].…”

Section: Target Systemmentioning

confidence: 82%

Density changes in low pressure gas targets for electron scattering experiments

Santiesteban

Alsalmi

Meekins

et al. 2019

Nuclear Instruments and Methods in Physics Research Section A:

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“…METHODS: Target details. A special target system was built to meet the goals of the tritium rungroup experiments 27,34 while satisfying all safety requirements for tritium handling 35 . Four identical aluminum cells, 25.00 cm long and 1.27 cm in diameter, contained gaseous deuterium, hydrogen, helium-3 and tritium, with areal densities of 142.2, 70.8, 53.2, and 84.8 mg/cm 2 (85.0 mg/cm 2 for the spring data taking on tritium) at room temperature 36 .…”

Section: Articlementioning

confidence: 99%

Revealing the short-range structure of the mirror nuclei 3H and 3He

Cruz-Torres

Santiesteban

et al. 2022

Nature

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When protons and neutrons (nucleons) are bound into atomic nuclei, they are close enough together to feel significant attraction, or repulsion, from the strong, short-distance part of the nucleon-nucleon interaction. These strong interactions lead to hard collisions between nucleons, generating pairs of highly-energetic nucleons referred to as short-range correlations (SRCs). SRCs are an important but relatively poorly understood part of nuclear structure 1-3 and mapping out the strength and isospin structure (neutron-proton vs proton-proton pairs) of these virtual excitations is thus critical input for modeling a range of nuclear, particle, and astrophysics measurements [3][4][5] . Hitherto measurements used two-nucleon knockout or "triple-coincidence" reactions to measure the relative contribution of np-and pp-SRCs by knocking out a proton from the SRC and detecting its partner nucleon (proton or neutron). These measurements [6][7][8] show that SRCs are almost exclusively np pairs, but had limited statistics and required large model-dependent final-state interaction (FSI) corrections. We report on the first measurement using inclusive scattering from the mirror nuclei 3 H and 3 He to extract the np/pp ratio of SRCs in the A=3 system. We obtain a measure of the np/pp SRC ratio that is an order of magnitude more precise than previous experiments, and find a dramatic deviation from the near-total np dominance observed in heavy nuclei. This result implies an unexpected structure in the high-momentum wavefunction for 3 He and 3 H. Understanding these results will improve our understanding of the short-range part of the N-N interaction.

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“…This experiment would also be useful in determining the EMC effect in the mass-three system [31]. Although providing a tritium target for JLab is straightforward [32], it is not trivial. The necessary tritium target has been developed for JLab and will be installed in 2016.…”

Section: Status Of High-x Experimentsmentioning

confidence: 99%

Quarks in Few Body Nuclei

Holt

2016

EPJ Web of Conferences

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Abstract. Electron scattering at very high Bjorken x from hadrons provides an excellent test of models, has an important role in high energy physics, and from nuclei, provides a window into short range correlations. Light nuclei have a key role because of the relatively well-known nuclear structure. The development of a novel tritium target for Jefferson Lab has led to renewed interest in the mass three system. For example, deep inelastic scattering experiments in the light nuclei provide a powerful means to determine the neutron structure function. The isospin dependence of electron scattering from mass-3 nuclei provide information on short range correlations in nuclei. The program using the new tritium target will be presented along with a summary of other experiments aimed at revealing the large-x structure of the nucleon.

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Thermomechanical design of a static gas target for electron accelerators

Cited by 6 publications

References 8 publications

Density changes in low pressure gas targets for electron scattering experiments

Density changes in low pressure gas targets for electron scattering experiments

Revealing the short-range structure of the mirror nuclei 3H and 3He

Quarks in Few Body Nuclei

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