FourStar Software Documentation

Warmup Procedure

Location of this document: http://instrumentation.obs.carnegiescience.edu/Software/FourStar/warmup.html

  • Preparations
  • Warmup


    FourStar Cooldown
    FourStar Software Documentation

    Preparations

    Please read the entire document before you start the warmup and familiarize yourself with the FourStar Sensors.

    Once you know that there will be a System Warmup it is recommended to not top-off the tanks any more than necessary for the remainder of the operations. In particular the detector tank should not be more than half full.
    It is safe to let the tanks run out of LN2 and let the temperatures drift up (passive warmup) provided that the system is on the turbo-pump and the ion-pump is turned off.

    Connect the dewar to the turbo-pump. You may leave the ion-pump on while the pressure is below 1.0e-5 [Torr] but it must be turned off once the tanks are warming up (tanks out of LN2). It is recommended to turn-off the ion-pump once the turbo-pump is running.

    Startup the FourStar software selecting just the Detector-, Optics-Temperature and TempControl-3 controllers, Front- and Back-Temperature monitors and the LN2-Controller (if available):

    The TempControl-3 temperature controller is not strictly necessary to warmup the system, but provides a considerable speed-up. The use of this 3rd temperature contoller requires a special cable to connect the tank heater with the controller heater output.

    Warmup

    Use the following settings on the temperature controllers:
    Setting Detector T.Controller (TC1) Optics T.Controller (TC2) Tank T.Controller (TC3)
    Target [K] 295 295 300
    |Max| [K/min] 0.04 0.02 0.04
    Range [W] 5 25 48
    Meta On On On

    During the warmup you should ensure that

  • The detector is never the coldest part of the system
  • The detector temperature is not more that 20 [K] warmer than the coldest part (typically the tank).

    Once the detector reaches about 270 [K] turn-off the heaters over night, or when you cannot check at least every hour.

    The diagrams below show a typical warmup: [todo use latest warmup]

    2012-01-30, Christoph C. Birk, Carnegie Observatories