User name R. Michaels
Log entry time 03:52:05 on January21,2008
Entry number 226524
keyword=alignment of thick PREX targetWe put in the 0.5 mm lead target.
We put 2 uA on target.
Ask for raster 6.5 x 5 in MCC units which will give us
4 x 4 in reality.
Run ... X ..... Y ..... T1 .... T3
......... (mm) ........ (Hz)
3080 .. +1.5 .. 0 ... 880 ... 620
3081 .. +3.0 ...0 ... 820 ... 600
3082 .. -3.0 ...0 ... 1150 .. 640
3083 ... 0 ... +2 ... 1020 .. 640
3084 ... 0 ... -2 ... 1020 .. 640
3085 ... 0 ... -4 ... 41K ... 7500 .. <-- Hitting ! (see fig 1)
3086 ... 0 ... +4 ... 16K ... 2800 .. <-- Hitting bottom now
but not as wide a swath of frame (fig 2)
So the center is at Y ~ +1 mm.
3087 ... 4.0 .. 0 .... 1600 ... 680
3088 ... -4.0 .. 0 ... 1300 ... 760
Conclusion:
X alignment has a fairly wide tolerance (as expected with
a 19 mm hole in X). Y alignment off by 1 mm and hits at 4 mm.
We will put the (X,Y) at (0,1) since that's close enough.
Next we will ramp the beam up to 60 uA to stress test
the PREX target at a current slightly above the proposal.
FIGURE 1
FIGURE 2
