Spare Parts
● The channeltrons should be protected from exposure to particle contamination.
Particles which become affixed to the plate can be removed by using a single-
hair brush and an ionized dry nitrogen gun.
10.2.1.2 Operation of the Multiplier
Microchannel plates and Channeltron detectors can be degraded by exposure to various
types of hydrocarbon materials which raise the work function of the surface, causing
gain degradation. Operation in a clean vacuum environment of 10
-5
mbar or better is
necessary in order to ensure the long-life characteristics of these devices.
10.2.1.3 Storage of the Multiplier
Due to the hygroscopic nature of the doped lead glass, it is important that the channel-
trons are stored properly.
Warning:
The shipping containers are not suitable for storage periods exceeding the delivery
time. Upon delivery to the customer‘s facility, channeltrons must be transferred to a
suitable long term storage medium.
● The most effective long term storage condition for the channeltron is a clean
(oil free) vacuum.
● A dry box which utilizes an inert gas, such as argon or nitrogen heated above
the dew point, is also suitable.
● Desiccator cabinets that utilize silica gel or other solid desiccants to remove
moisture have been proven to be unacceptable.
10.2.2 Change a Channeltron
A multiplier loses its gain with operating time. It should be changed when a significant
degradation in amplification (i.e. intensity) is experienced or the detector voltage limit
of the control unit is reached.
10.2.2.1 Removing the Detector Flange
● Switch off the analyzer supply.
● Remove both the detector and analyzer connections.
● Vent the system.
● Open the detector flange, let the detector unit down slowly and put it carefully
on a table.
(Three springs, pressing the detector assembly to the groundplate may exert
some force downward when the screws are released.)
10.2.2.2 Replacing Channeltrons
● Note: Use dry nitrogen only in order to remove dust or lint.
● Loosen the three screws at the top plate and remove the plate.
82 PHOIBOS
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