1. DHB, nEDM Collab. Mtg, 15/16 Apr 04 UIUC Test System (Beck, Chandler, Hertzog, Kammel, Newman, Peng, Sharp, Williamson, Yoder; Blackburn, Kenyon, Thorsland) Goal: Provide cooled environment to test experiment components at operating temperature -½ scale cells -¼ scale magnet assemblies Two stage cooling -pumped L 4 He cools to T = 1.3 K, liquifies 3 He -pumped L 3 He cools to T < 0.5 K -experimental “platform” on L 3 He vessel -main advantage is short turnaround time 3 He gas storage LHe Dewar

2. DHB, nEDM Collab. Mtg, 15/16 Apr 04 3He Refrigerator: LHe Vessels 3 He gas storage L 4 He pot (1.3 K) L 3 He pot (0.5 K) Vacuum flange

3. DHB, nEDM Collab. Mtg, 15/16 Apr 04 -maximum 6 h at 0.5 K – valve on turbo pump? -replacing instrumentation leads with superconductor to reduce heat leak -preparing for first cooldown with glass cell -SQUID noise test? 3He Refrigerator: First test Start L 4 He pump Start L 3 He forepump Start L 3 He turbopump L 3 He vessel empty First cooldown: T room to 0.54 K in 11 hours

4. DHB, nEDM Collab. Mtg, 15/16 Apr 04 UIUC: Polarized 3He Development Goal: test t relax with dTPB surface at operating temp I.Metastability optical pumping -commission new diode laser system at 1083 nm 2s 0 23s123s1 23p223p2 23p123p1 23p023p0 1083.034 nm 1083.025 nm 1082.908 nm 4 He excited states 23p023p0 23p123p1 23p223p2 -splitting of lines gives d /dT = 0.076 nm/ o C (spec 0.08 nm/ o C ) -width of lines is 2.8 GHz FWHM: consistent with experience 3031323334 Laser Temperature ( o C) Flourescence signal (V) 0.09 0.10 0.11 4 He

5. DHB, nEDM Collab. Mtg, 15/16 Apr 04 -preparing NMR system and 668 nm polarimeter for room temperature test UIUC: Polarized 3He Development I.Metastability optical pumping -3He flourescence – seen? → gas may be contaminated 2 3 s 3/2 2 3 p 3/2 2 3 p 1/2 1083.031 nm “C9” 3 He excited states 23p023p0 23p123p1 23p223p2 1082.81083.01083.21083.4 Laser Wavelength (nm) 3 He (3/30) Flourescence signal (V) 0.069 0.070 0.071 0.072 0.073 2 3 s 1/2 2 3 p 3/2 2 3 p 5/2 1083.057 nm “C8” C8?

6. DHB, nEDM Collab. Mtg, 15/16 Apr 04 UIUC: Polarized 3He Development II.Glassware and holding field for cryostat -start with simple double cell system to reproduce Duke 4 K results -5 G holding field with minimum gradients (Hayden design) -13 coils: uniform field (  B 2  1/2 /B  10 -4  -volume ~ 7 cm dia x 2.8 m -completing coil shunts Pumping cell Vacuum seal Mirror  B z,RMS /B z z (radii)

7. DHB, nEDM Collab. Mtg, 15/16 Apr 04 UIUC: Polarized 3He Development III.Circulating system -a la Candela, Hayden & Nacher -force 3 He to circulate past pumping cell -aid entrainment of 3 He into L 4 He with HEVAC effect -detailed model developed -measure relaxation -test SQUID pickup with very low concentrations?

8. nEDM Cryostat Layout E 300 mK vessel (incl. graphite HV plane, BN x or Gd paint neutron shielding) Elements Variable capacitor Possible 1K shield Inner coil for B rf, flip Outer coil for B rf, flip 4K vessel Coil for B 0 field Metglas (inner) ferromagnetic shield Superconducting shield 4K vessel Mu-metal (outer) ferromagnetic shield Liquid nitrogen shield Cryostat wall y x z B0B0 B rf 1.79 m o.d. D. Beck 4 Jun 03

9. nEDM Cryostat Layout E Elements 300 mK vessel (incl. graphite HV plane, BN x or Gd paint neutron shielding) Variable capacitor Possible 1K shield Inner coil for B rf, flip Outer coil for B rf, flip 4K vessel Coil for B 0 field Metglas (inner) ferromagnetic shield Superconducting shield 4K vessel Mu-metal (outer) ferromagnetic shield Liquid nitrogen shield Cryostat wall y x, B 0 z B rf D. Beck 4 Jun 03 1.79 m o.d. 3.06 m long

10. DHB, nEDM Collab. Mtg, 15/16 Apr 04 Dressed Spins: Principle interacting system of magnetic moment and photons -effective moment is reduced (“dressed”) -precession rate is reduced depending on “bare” magnetic moment adjust dressing parameter, x, to critical value, given by → field for  rf = 2  *1kHz is 0.41 G

11. DHB, nEDM Collab. Mtg, 15/16 Apr 04 Dressed Spins: Practice use cos  coils for both B 0 and B rf -use 2 opposed cos  coils for B rf -reduces power dissipated in ferromagnetic shield -“rf ” frequency -because for small changes in B 0,  E ~ (  0 /  rf ) 2  0, →  rf ~ 100  0, or  rf ~ 2   1 kHz -also use B rf coil for  /2 pulse Inner coil for B rf, flip Outer coil for B rf, flip Coil for B 0 field y x z B0B0 B rf Metglas (inner) ferromagnetic shield

12. Cos  Coils Central field0.41 G Number of turns20 Inner radius0.45 m Inner length2.5 m -note: ends not shaped (for these results) – to do

13. Outer Cos  Coil minimum power dissipated in shield “soft” function of outer coil size -t shield = 10 layers Metglas 2705M Dissipated Power (W) Inner coilShield Outer radius (m) 1800 integration points 450 integration points 200 integration points

14. DHB, nEDM Collab. Mtg, 15/16 Apr 04 Field Distributions For r i = 0.45 m (4.5 A), r o = 0.6 m (-2.4 A), r shield = 0.66 m B rf (y)/B rf,0 y (m) B rf (y) (G) B rf (x)/B rf,0 x (m) B rf (x) (G)