BERTHOLD TECHNOLOGIES LB 3602, Руководство по эксплуатации

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LB 379
26
Adjust current input Current input adjustment
Target value:/Actual value
Adjustment of input current. Feed current of 1.8 mA.
Confirm display with <enter>.
RUN appears on the display, the adjustment is running. Push
<more> to stop the adjustment and continue with the next
item.
Then feed 18 mA current and confirm with <enter> and push
<more> to continue.
6.1.1 Checking the Crystal-Multiplier
Assembly
A plateau that is too small or too steep indicates faults in the
crystal-multiplier assembly.
Please proceed as follows to perform a visual inspection of crys-
tal and multiplier:
Switch off the scintillation counter before opening the in-
strument.
Do not perform the check in bright daylight, as this may
damage the photo cathode of the photomultiplier.
Figure 8: Assembly of the scintillation counter
Open the scintillation counter by removing the cover of the con-
nection box first and then the screws of the base. The entire
electronics (1) with the crystal/multiplier combination can then
be detached from the housing.
Remove photo multiplier combination from base (2) and un-
screw ring nut (3) on front panel. The multiplier (4) including
crystal (5) can now be detached from the Mu-metal shielding
(6).
A thin layer of silicone oil between crystal and multiplier ensures
optical coupling; silicone oil is rather viscous, particularly at low
temperatures. Carefully detach the crystal from the multiplier
window by gently sliding the crystal sideways.
Do not wipe off the silicone oil layer if no new silicon oil is avail-
able!
(a)
(b)
(c)
3
5
4
6
2
1
1 = electronics part with
(a) CPU,
(b) HV, (c) voltage divider
2 = base
3 = ring nut
4 = photomultiplier
5 = crystal
6 = Mu-metal shielding