TonyS, FranciscoL, [Remote: RickS]
After one week of having the inner beam left by 5mm on the Rx sensor (alog 78373), on June 18, we moved the beam from left to center.
It is very important to note that this procedure had a different order than the movements done previously. The purpose of the procedure - move the inner beam 5 mm to investigate sources of systematic uncertainties on the pcal system - is not affected by this change. The intention of changing the steps of the procedure is to see more clearly any unexpected changes introduced by moving the beam, especially in the optical efficiency.
For the previous movements, the target would always remain in the Rx_PS. During this procedure, the outer beam is blocked before placing the target.
AlignedTarget.jpg shows the alignment with the beam height gauge. The file EndStationLog.pdf lists the voltage values after each significant step of procedure T2400163. The steps represent writing down a voltage value after a particular change to the beam position. Some highlights from the recorded values.
- ("Inner beam, no target") Only inner beam at Rx detector. See InnerBeamBefore.jpg - note, the beam height gauge was removed before moving the beam.
- ("Inner b. no target") Finalized beam movement and recorded the voltage from the Rx sensor with the inner beam only. See InnerBeamAfter2.jpg. Voltage of 1.684V is 0.12% from previous position (1.682V). There are discussions to make a calibration measurement at each position of the inner beam as a continuation of this series of measurements. Also should track the optical efficiency given by
PCALX_FORCE_COEFF_OPT_EFF_LIVE_OVER_REF - ("Botb. no targ.") Both beams, no target. The measurement was recorded after removing beam block on outer beam and removing the target. The measurement of 3.388V is higher by 0.17% from initial measurement (3.382V).
The 'Initial' measurement is *equal* to the last voltage measurement from the previous movement, done on June 11 (alog 78373). The initial and final voltage measurement during today procedure changed by 0.17%.
