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The OTR viewer at 2C23 (at the last quad stand ~2m upstream of
tagger) has been changed to a "normal" viewer. This will provide
a visible spot for the tuners.
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The radiator targets have been replaced. From the initial examination
it is hard to tell if the radiators failed due to:
a) beam heating
b) turbulence from pump down/bleed up
The radiators are as follows:
insert direction ->
---------------------------------
/ /\
--------/ D C B A / \
--------\ / \ BEAM North-->
\ / \
---------------------------------
<- retract direction
A: 5*10^-5 radiation length
B: 1*10^-5 "
C: 5*10^-6 "
D: 1*10^-6 "
This is the REVERSE order compared to the previous installation!
Hopefully by having
the thinest radiator furthest from the beam pipe will reduce the
wind during pump down and bleed up.
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Photon Beam profile:
A 2mm steel wire has been installed in the pair-spectrometer converter
box. Hopefully correlating movement of this wire with scaler counts
in the pair-spectrometer or pair counter will enable us to measure the
photon beam profile at the downstrem devices. Mike Klusman fabricated
and installed the hardware. Yannick Patois is working hard on the
software. The wire will provide two orthogonal profiles (u and v
rotated 45 degrees from the lab coordinate system x and y).
Arne