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Processing Subsystem

Processing Subsystem

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Processing Subsystem

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  1. Processing Subsystem DHB/UIUC 25 Jan 06

  2. Schematic → 3He • Purifier pump B being regenerated Purifiers (D. Haase) Collection Bh1 Bh2 V7 Charcoal Charcoal “Piston” Bh3 B0 V1L V6A (open) V6B (closed) V4 V2 Cell L V5 V3 Cell R V1R

  3. Proposed Cycle (A) • Measure (V2, V3 closed): T = 0 – 1000 s • Flip spins, measure n precession • Collect polarized 3He • Purify LHe in purifier, collection volumes (V4, V5 open): T = 0 – 885 s (?) • Close V4, open V7: T = 885 – 895 s • Collect polarized 3He: T = 895 – 995 s • Close V7: T = 995 – 1000 s • Reduce electric field (close capacitor): T = 1000 – 1020 s • Open V2: T = 1020 – 1025 s • Decrease cell pressure (release piston): T = 1025 – 1035 s • Open V1L, V1R, V3: T = 1035 – 1050 s • Purify ‘cell’ LHe: T = 1050 – 1250 s • Close V5, open V4: T = 1250 – 1260 s

  4. Proposed Cycle (A) • Load polarized 3He into cells: T = 1260 – 1270 s • Close V3, open V5: T = 1270 – 1280 s • Increase cell pressure (load piston): T = 1280 – 1290 s • Close V2, V1L, V1R: T = 1290 – 1305 s • Increase electric field (open capacitor): T = 1305 – 1315 s • Open n shutter: T = 1315 – 1320 s • Accumulate n: T = 1320 – 2320 s • Close n shutter: T = 2320 – 2325 s • Measure: T = 0 – 1000 s

  5. Proposed Cycle (B) • Flip spins, measure n precession (V2, V3 closed): T = 0 – 1000 s • Reduce electric field (close capacitor): T = 1000 – 1020 s • Open V2: T = 1020 – 1025 s • Decrease cell pressure (release piston): T = 1025 – 1035 s • Open V1L, V1R, V3: T = 1035 – 1050 s • Purify ‘cell’ LHe: T = 1050 – 1250 s • Close V5, open neutron shutter: T = 1250 – 1260 s • Loading: T = 1260 – 2260 s • Load neutrons into cells • Collect polarized 3He • Purify LHe in purifier, collection volumes (V4, V5 open): T = 1260 – 2145 s (?) • Close V4, open V7: T = 2145 – 2155 s • Collect polarized 3He: T = 2155 – 2255 s • Close V7: T = 2255 - 2260 s

  6. Proposed Cycle (B) • Open V4: T = 2260 – 2265 s • Load polarized 3He into cells: T = 2265 – 2275 s • Close V3, open V5: T = 2275 – 2285 s • Increase cell pressure (load piston): T = 2285 – 2295 s • Close V2, V1L, V1R, neutron shutter: T = 2295 – 2315 s • Increase electric field (open capacitor): T = 2315 – 2325 s • Measure: T = 0 – 1000 s

  7. Valve States

  8. Valve Types • 9 physical valves, 7 different valve ‘numbers’ – expect 6 different types • Type 1: V1L/R (T = Tcell) • aperture and conductance consistent with purification time • neutron friendly • polarized 3He friendly: dTPB on inner surface • no electrical conductors, non-magnetic, non-superconducting • note: makes hole in lightguide – what is least damaging location? • ground plane continued across ‘outside’ surface of valve ‘stem’ • actuator based on main downstream flange • actuator mechanism at radius of E field return, then at right angles to ‘300 mK’ vessel axis • gap consistent with n, pol’d 3He lifetimes (~1 mm) • no pressure drop

  9. Valve Types • Type 2: V2 (T = Tcell) • polarized 3He friendly, especially in closed position • non-magnetic, probably non-superconducting • actuator based on main downstream flange • no pressure drop • could be just ‘superleak’ (no moving parts) • Type 3: V3 (T = Tpur – Tcell) • Dp = 1 atm when closed: superfluid He ‘tight’ (perhaps 1/10 mm gap) • polarized 3He friendly • non-magnetic, probably Snon-superconducting • actuator based on main downstream flange

  10. Valve Types • Type 4: V4, V5 (T = Tpur) • polarized 3He friendly, especially V4 • non-magnetic, non-superconducting • actuator based on main downstream flange • no pressure drop • ‘shutter-like’ • collection volume must also be at Tpur (pvap < 10-6 T?) • Type 5: V6 (T = Tpur) • reasonably vacuum tight (isolate charcoal for regeneration) • essentially zero pressure drop • large aperture (~ 30 cm) • actuator based on main downstream flange

  11. Valve Types • Type 6: V7 (T = Tpur – Tsrc) • polarized 3He friendly • non-magnetic, non-superconducting • actuator based pol’d 3He source • no pressure drop • ‘shutter-like’

  12. * Only in thin films or at high pressure