Chapter 9 Maintenance
Mini-Switch LB 471
9.4.2 Checking the Crystal-Multiplier Combination
Often, faulty parts can easily be detected through visual inspection
of crystal and multiplier.
Crystal
Magnetic shielding
(Mu-metal)
Photomultiplier
Optical connection
Crystal has to be replaced if
the crystal appears to be crys-
tal-clear inside, does not have
any cracks nor milky spots and
has a slightly greenish color-
ing.
the crystal shows a clear yel-
lowish to brownish coloring.
Multiplier has to be replaced if
the vapor deposited layer in
the multiplier window (photo
cathode) has a slight brownish
or tinted glass like coloring.
the vapor deposited layer is no
longer available or spotted
(cathode destroyed e.g. due to
overheating, breakage of glass
or incidence of light).
If no errors are visible, you can check the function of the crystal-
multiplier combination by performing a plateau measurement.
Figure 45:
Multiplier-crystal
combination
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