Summary

This document describes the procedure for filling DEIMOS with liquid nitrogen (LN2) cryogen which is required to maintain the CCD temperature.

Advisories

WARNING: EXTREME COLD! Do not attempt to perform fill without proper safety gear

Procedure

  1. Toggle rotator control hand paddle switch to MANUAL.
  2. On hand paddle, select: (Note: If the 170L dewar is on the opposite side of instrument, select #2=FILL L.) Depress either FWD or REV button to rotate.
  3. When instrument rotation is complete, set the band brake on the front left side of DEIMOS (as viewed from behind DEIMOS looking toward the telescope) to full down position to prevent any inadvertent rotation moves. See figure 1.
  4. Connect LN2 transfer line quick disconnect (QD) tip to instrument fill port.
  5. Slowly open the liquid valve on top of the 170L dewar. Caution: Stand clear of gas plume venting from side port on DEIMOS.
  6. Transfer LN2 until liquid cryogen begins to flow from DEIMOS vent port.
  7. Close the liquid valve on the 170L dewer.
  8. Disconnect LN2 transfer line from DEIMOS LN2 fill port and place QD tip in stow holster.
  9. Return DEIMOS band brake handle to the unlocked up position to release the brake.
  10. Toggle the rotator control hand paddle switch back to COMPUTER. Verify all light indicators extinguish.

Figures

Figure 1. DEIMOS band brake
Image showing DEIMOS band brake
Band brake. Push lever down to engage. Pull up to release.