Canberra 2015A, User Manual

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Resolution Destroying Interfaces
1. Vibration transmitted to the detector and cryostat. This can be through the
floor or mounting, as well as direct audio coupling through the air. Vibration
isolators in the mounting and sound absorbing covers around the detector can
reduce this problem.
2. The close proximity of a radio station can be picked up by the “dipstick” of
the cryostat. Good contact between the dipstick and the cryostat can often
help solve this problem. Beware of grounding the cryostat and dipstick as
this may increase power line frequency (50 or 60 cycle) ground loops.
3. Ground Loops: power line frequency interference can be caused by long
cable connections between the detector, preamplifier, and shaping amplifier.
There is no general solution for this problem. As a first step, the preamp
should use the power supplied by the main shaping amplifier. Second, the
system should have a single point house ground. For example, on a general
system connect the NIM Bin to house ground via the ac line cord. Isolate all
other equipment requiring ac voltage from the house ground. Connect all
chassis’ in the system to the grounded NIM Bin using heavy braided wire.
14
Operating Instructions
Figure 13 Internal Shaping Components