SPECS 2D-CCD, User Manual

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Manual V2.docx | Status 10.12.2015 | Version 1
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The MCPs show a slow decrease in sensitivity after prolonged use. For that reason,
you need to increase the detector voltage periodically.
Maximizing the lifetime of MCPs 6.10
MCPs are delicate devices and need careful handling to ensure long lifetime and good
performance. The information presented below represents best practice for using MCPs.
Caution!
Failure to observe the precautions in this section can lead severely reduced performance or
even the destruction of the MCPs.
6.10.1 Storage
If the MCPs are exposed to air for more than one day, they can develop small fissures which
seriously affect their operation. It is therefore essential to keep the MCPs under vacuum.
The detector should therefore be stored or transported in the transportation case. This can
be pumped. A storage vacuum obtained from a roughing pump (<10
−3
mbar) is sufficient.
The vacuum must be oil-free.
6.10.2 Operating voltage
The test report supplied with the detector includes the correct operating voltage. Exceeding
this voltage can dramatically reduce the lifetime of the MCPs.
However, the performance of the MCPs degrades over time. In this case, you need to
increase the operating voltage.
6.10.3 Bakeout
After each bakeout, the analyzer needs 2–3 days to cool down.
If MCPs are operated at higher temperatures (>60 °C) they can suffer severe damage. Some
channel electron multipliers will lose gain and exhibit a markedly higher detector plateau.
The interior parts of the PHOIBOS analyzer will cool down significantly more slowly than the
case. For this reason, we recommend that you wait for a complete cool down of the detector
assembly—at least 2 days.
Even if the analyzer case is cold, any internal parts on insulators may still be too hot for safe
operation. Make sure that all users are aware of the issue and take the necessary
precautions.