| DATE |
MAINTENANCE |
| 24 Jun 2008 |
dewar removed from C9 |
| 30 Jun 2008 |
opened refrig, cleaned and vacuum baked displacers noted that Envex sleeve on stage3 displacer is badly cracked SS section of displacer measures 0.496 to 0.4955 dia replaced carbon bushings and Kap-Seal; also installed new dowel pins in valve clothespins new stage3 seal, reuse stage1 and stage2 seals install prototype welded electrical feedthrough because pin 1 is pushed back on old feedthrough Dusty repolished the radiation shields, which were badly tarnished note that slots in base of radiation shield are uncomfortably narrow for wire bundles removed 3mm mixer and amp, installed HIA-188, WBA13 131D |
| 06 Jul 2008 |
lab test; temps are 60 / 14 / 3.3 / 3.4 / 3.4 K |
| 09 Jul 2008 |
installed on C12 |
| 09 Jul 2010 |
removed from C12; stage3 had been running at 5 - 5.5 K |
| 20 Jul 2010 |
opened refrig, cleaned cylinder and displacers (did not seem exceptionally dirty) replaced stage3 seal (not worn through), reused stage1 and stage2 seals stage2 seal thickness ranges from 0.059 to 0.063" Envex section of stage3 displacer measures 0.4993 at base, 0.475 at tip; Scotch yoke bushings seem OK |