20180419

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Today's activities

• This morning, the temperature rising of the WAB dummy seemed not stop by the heat inputting since the last evening.
• Even in noon the rising rate seemed not changing; eventually it was approaching 66K.

• Hoping it reached in equilibrium, I calculated the change of derivative coefficient (K/hours) roughly from the collected measured temperature data so far, and found the derivative was asymptotically approaching a non-zero value: about 0.35K/hours!

• So, I gave up waiting the equilibrium, and reduced the input power to be about 1.3W to the WAB dummy .
  • The power source (Agilent E3630A) shows 0.24A, 7.12V.
  • Simply calculating, the power consumption is 0.24A x 7.12V = 1.70W, and the total resistance is 7.12V/0.24A = 29.7 ohms.

  • Actually, the part of the total resistance should be the "heaters". By the yesterday's estimation, it would be around 22 ohms now (in the cryogenic temperature), but difficult to be sure, as resistance would vary w.r.t. temperature; assuming the number, the heaters would supply 0.24^2 * 22 = 1.26 W so I wrote about 1.3W.

  • Let's see.

Next plan

• Check the balance of the suspended WAB with some wires and sensors are attached.
• Check how the damping would be now after the replacement of the damping magnets.
• Check the reproducibility of the alignment of the suspension among several modes.
• Check heights of several points.
• Take care of water spring??

Wanted!

• Good rail(?) to move the WAB suspension in the cryostat in the main beam direction.

• Chain block? to support the load in the chamber.