Polarized 3 He Target for 12 GeV Experiments J. P. Chen, August 15, 2012, JLab Experiments and requirements Target performance from previous experiments Upgrade/design / R&D consideration and status (Gordon) Hall C / A compatibility and special consideration (Patricia) Discussion on cost, manpower, schedule consideration (All)
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Polarized 3 He Target for 12 GeV Experiments J. P. Chen, August 15, 2012, JLab
Polarized 3 He Target for 12 GeV Experiments J. P. Chen, August 15, 2012, JLab. Experiments and requirements Target performance from previous experiments Upgrade/design / R&D consideration and status (Gordon) Hall C / A compatibility and special consideration (Patricia) - PowerPoint PPT Presentation
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Polarized 3He Target for 12 GeV Experiments J. P. Chen, August 15, 2012, JLab
Experiments and requirements
Target performance from previous experiments
Upgrade/design / R&D consideration and status (Gordon)
Hall C / A compatibility and special consideration (Patricia)
Discussion on cost, manpower, schedule consideration (All)
Experiments and Requirements
12 GeV Polarized He3 Experiments
Total 7 approved experiments using polarized He3 target
Hall A: 1) A1n: BigBite/HRS, upgrade luminosity (3x1036?)
• Magnet: existing ones or new design? • Support structure: upgrade/improvements?
or new design?• Polarization measurement:
pulsed NMR needed for metal cellsabsolute calibration (AFP): EPR and/or water?
Options, Manpower, Cost, Schedule?
Goal: meet experiment needs within budgetary constraints One path: upgrade to have luminosity by a factor of 3 first (A1n-A, d2n-C) then another a factor of 3 in 2nd stage (GENII, A1n-C) Length of target cell?
Mechanical support/motion system • Design manpower /costs
Option A: simple design/existing magnets/minimum modification/not full size guesstimation: design/engineering: ~ 1-2 man-year (similar to transversity)
cost: ~ $ 370-500K (similar to transversity/d2n...) Option B: large size pumping cell /mostly new design guesstimation: design/engineering: ~ 3-4 man-year (similar to GEn)
cost: ~ $ 1M Need R&D/design activities by the user groups and at Jlab User contributions are essential
Options for A1n-A running from Gordon
Option Cost Performance ------------------------------------------------------------------------------1) Transversity target as is 200K 1/3 Luminosity2) Trans. w convection (minimal) 300K 1/2 Luminosity 3) Trans. w convection (full) 375K 2/3 Luminosity 4) Double-pumping ch. w conv. 0.5-1.0M Full Luminosity
Gordon: “(We) would like to present you with an idea that might allow the Hall A A1n experiment to remain in the running for early (first?) running….we advocate going with option 3.”