Polhe3 cell wall thickness measurement
measurement for transitivity cell with ultra sonic gauge
Here we used the ultrasonic thickness gauge to measure the glass cell wall thickness. We did the measure for Cell Astralweek, Maureen and Brady.
Firstly we did a calibration for the velocity. Then we pressed the probe on the surface and it worked very well as long as kept straightly.
For the transfer tube wall, we measured three different points. One point is close to pumping chamber, one point is in the middle and another one is close to target chamber. For target and pumping cell, we choose 3 separated points to do the measurement.
1. Maureen
a. Transfer tube wall thickness: 1.63mm 1.62mm 1.64mm average: 1.63mm
b. Target chamber wall thickness: 1.54mm 1.52mm average: 1.53mm
c. Pumping chamber wall thickness: 3.02mm 3.10mm average: 3.06mm
2. Astralweek
a. Transfer tube wall thickness: 1.59mm 1.59mm 1.58mm average: 1.587mm
b. Target chamber wall thickness: 1.58mm 1.64mm 1.58mm average: 1.60mm
c. Pumping chamber wall thickness: 3.05mm 3.19mm 3.33mm average: 3.19mm
3. Brady
a. Transfer tube wall thickness: 1.36mm 1.26mm 1.36mm average: 1.327mm
b. Target chamber wall thickness: 1.44mm 1.40mm 1.38mm average: 1.407mm
c. Pumping chamber wall thickness: 2.8mm 2.84mm 2.54mm average: 2.727mm
Brady appears to be thinner
about ultra sonic gauge
note: it's bit tricky of using the ultra thickness gauge on the curvy glass surface. you need to press it STRAIGHT on the surface and hard (but not too hard to break glass). The liquid coming with it is a must have to have some reading. First a calibration is needed with its built in calibration button and a known thickness of the same type glass (a broken cell). then the number still can jump around in the order of 0.01mm depending how stable your hand is. but the error is certainly controlled at 0.1mm level. We could check how thin the gauge can measure, but the pressure it needs make it impossible for our target window thickness measurement.
source: borrowed it from RF group. Andrew Burill (aburrill@jlab.org) and Era Perry (elperry@jlab.org)
https://www.olympus-ims.com/en/45mg/
measurement for transitivity cell with laser interferometer
Yi Zhang summarized the results in the file
http://hallaweb.jlab.org/equipment/targets/polhe3/lab/ccell/he3_cell.pdf
Three cells have similar thickness. Brady is not thinner which is different from ultra sonic measurement.
We shall redo Brady measurement with ultra sonic when the new cell comes
