40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
  ATF eLog  Not logged in ELOG logo
Message ID: 2583     Entry time: Tue Jun 8 12:58:40 2021
Author: Stephen 
Type: DailyProgress 
Category: Cryo vacuum chamber 
Subject: Maximum power for temperature actuation 

Quick log establishing the maximum power for our thermal actuation:

Heater: HSA25100RJ from TE, unknown sourcing. Acetone wiping cleaned off p/n and markings from body, should engrave at next opportunity, but [Attachment 1] from many months ago shows the p/n. Note that this is not the current mounting configuration - [Attachment 2] is more similar to current mounting. Anyway, according to the datasheet (now added to the QIL wiki at Documentation > Manuals) this heater is rated for 25W and has a resistance of 100Ω.

Leads: unknown, and not super important unless we had tiny hair conductor - I am not in lab presently, but it appears from our connector (Lesker FTACIR19AC) that we must have 20-24 AWG,

Carrying the 7, the current through the Heater will be 0.25 A at max actuation, and the 20-24 AWG insulated copper leads will have plenty of ampacity for this load (plus, they are cooled, so normal current capacity considerations fly out the window a bit).

Conclusion: 25W actuation will be the limit that we will apply in the CTC100 temperature actuation routine.

From first trials yesterday, the response at ~20W (at starting temperatures around 80K) appears to be on the order of 1 degree per minute, which should be just fine for actuating to maintain a +/-  1 degree constant setpoint with static thermal loads. More to follow on trials implementing temperature control.

Note that the QIL Wiki points to the DCC (which contains a budget that was helpful resources to trace these purchases), the datasheets and other documentation, and also points to the QIL Cryo Vacuum Chamber photo album, which hosts the images below.

Attachment 1: IMG_8495.JPG  2.397 MB  | Hide | Hide all
Attachment 2: IMG_8745.JPG  3.131 MB  Uploaded Tue Jun 8 14:37:08 2021  | Hide | Hide all
ELOG V3.1.3-