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 0.4K/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; assuming the number, the heaters would supply 0.24^2 * 22 = 1.26 W.

  • 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.