11
automatic enable only if detector damage or any hazard due to high voltage is reliably
excluded.
If the outputs are disabled they can be enabled via the ‘Enable Outputs’ button at the bottom
of the main panel.
Controls for Power Outputs and Detector Gain
The main panel is structured into ‘Connector 1’,
‘Connector 2’, ‘Connector 3’, and ‘Cooling’. To
switch on or off one of the output signals click on
the corresponding button. The detector gain
control signals are changed by dragging the
vertical bars or by typing in a value between 0 and
100%. Please note, that the Gain / HV signals
control the high voltage of the detectors.
Therefore, the detector gain is not proportional to
the control signal. For PMTs and MCPs the
relation is approximately
GAIN = V
control
n
with n ranging from 2.5 to 5. Therefore, the
relation is highly nonlinear, and the PMT gain
varies over several orders of magnitude. Don’t be
surprised that photon counting works only at a HV
setting close to the maximum.
Detector Overload
If a PMT overload is detected the ‘OVLD’ light of
the corresponding connector turns on and a
warning (flashing ‘!’) is issued. At the same time
the detector control signal and the +12 V at the
corresponding connector are shut down. You can
also disable the high current switches on overload,
e.g. to close shutters. To disable the switches from
the overload flip-flops of connector 1 or 2 jumpers
on the DCC board have to be set.
To switch on the detector(s) after an overload
shutdown, click on the ‘RESET OVLD’ button.
Make sure that the overload has been removed
before you reset the detectors.
Safety note: Please make sure that you don’t
exceed the maximum values for your detector(s).
Particularly, if you control a HV power supply,
make sure that it is safe to turn on or increase the
voltage. Although the DCC-100 contains some
safety features, such as detector shutdown at
power-on or overload, it cannot be made safe in terms of operator errors, such as turning on
HV power supplies with open or wrong connected output cables, or exceeding the maximum
operating voltage for a given detector. bh will not take responsibility for accidents or detector
damage resulting from setting or loading values exceeding maximum values for a given
experiment setup.
DCC main panel, detectors activated
DCC main panel, after overload
