On this shift, we were supposed to perform runs examining the trigger rate
and beam lifetime as a function of the beam current. However, our first
run had trigger rates simply too high (they were around 9300Hz at 90mA and
dropped to around 400Hz at 20mA).
Thinking that the beam might be clipping the collimator, we started
playing with the beam position. We examined the trigger rate and beam
lifetime as we shifted the beam respectively up, down, left, and right of
the initial position by 1mm. The results were that the rate dropped the
most (yet was still fairly high (around 5500Hz at 80mA)) 1mm BELOW the
initial position (the initial position was x = -9.37mm, y = -3.69mm).
At 2mm BELOW the initial position, the rate dropped even more (to around
3700Hz at 80mA).
At 3mm BELOW the initial position, CCR couldn't get the beam current above
30mA.
All results are in the lab book.
Aaron and Adrian
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