ITC503: control at <5K

[Tom-Willemsen]

As an instrument scientist on ZOOM, I would like my ITC503 controller to be able to cool down a cryostat to less than 5K.

Current behaviour:

• The ITC503's PID tables increase the flow of liquid Helium to try to cool down the cryostat. This can only get to ~5K (boiling point of 4He is ~4.2K). Hence, the ITC503 continuously pours 100% helium onto the cryostat (in automatic PID controlled mode).

Requested behaviour:

• As above for T > 5K
• Below 5K, need to decrease the flow of helium and instead activate a pump somewhere (to reduce the pressure) and hence cool to T = ~2K

Notes

• The ITC503 is physically capable of doing this (the scientist set it up using the front panel) but we do not provide a remote interface for it.
• We will require input from cryogenics to find out:
  • What this entails
  • Whether the ITC503 is capable of doing this remotely (I have not checked that appropriate commands exist)
  • If other "special" configurations of ITC503 may exist (3He sorb?). We should discuss what can go in the "general" driver and what is specific to a particular experiment with cryogenics.
• The first step of this ticket is to have a meeting with cryogenics.

Acceptance criteria

• [ ] An ITC503 temperature controller can adequately control the temperature of a cryostat down to ~2K

[Tom-Willemsen]

After discussion with cryogenics, Dave Bunce is going to have a chat with Diego about this, it appears some information has got lost somewhere along the way. The existing ITC503 driver should already be able to achieve what is needed (apparently).