2.3 Pmt (Photo Multiplier Tube); 2.4 Photo Diode - CPI Indico 100 Series Service And Installation Manual

3E
ABS Calibration
WARNING: SWITCH
DISCHARGED BEFORE CONNECTING ANY ABS PICKUP DEVICES
3E.2.3 PMT (Photo Multiplier Tube)
NOTE: The generator must be fitted with the "Universal AEC Board" assembly if using a PMT. The high
voltage supply for the PMT is located on this assembly.
1. Dress the PMT cable from the imaging system such as to allow the dynode high voltage lead to plug
into the "universal AEC interface board" at J7. Refer to figure 3E-4. J7 is the high voltage output for
the PMT, all pins on this connector are connected in parallel and thus any of the 4 pins on J7 may be
used. Ensure that the high voltage lead is rated at 1000 VDC minimum.
NOTE: The total resistive load of all dynodes must be greater than 1 megohm to prevent excess PMT
power supply loading.
2. Dress the signal (coax) cable from the PMT to allow it to connect to J7 on the generator interface
board. Wire to J7 as per figure 3E-3. Alternately, the PMT output may be connected to BNC connector
J8 on the generator interface board.
3. Ensure that there is sufficient slack in the cables such that the cabinet door does not strain these
cables when opening and closing. Secure the cables in place such as to prevent mechanical stress on
the connections.
4. The signal ground must be at the generator interface board only to avoid ground loops.
5. Position the jumpers on the generator interface board as per table 3E-2 for Photo Multiplier Tube,
selecting the correct configuration depending on whether the input is at J7 or J8.
6. The PMT high voltage calibration will be done at a later step.
3E.2.4 Photo Diode
1. Dress the signal cable from the photo diode circuit to allow it to connect to J7 on the generator
interface board. Connect the photodiode to J7 as follows: Output signal to pin 12, ground to pin 7, +12
VDC to pin 4, and -12 VDC if used to pin 5.
2. Ensure that there is sufficient slack in the cable such that the cabinet door does not strain this cable
when opening and closing. Secure the cables in place such as to prevent mechanical stress on the
connections.
3. Note that there are three types of photo diodes for this application with outputs as listed below:
•
a zero to positive DC voltage for increasing light flux
•
a zero to negative DC voltage for increasing light flux
•
a negative DC voltage to positive DC voltage for increasing light flux. The required dose is set for
0 volts. The output will be negative for reduced light due to increased patient absorption, then
swinging positive for increased light due to reduced patient absorption.
4. Position the jumpers on the generator interface board as per table 3E-2 for Photo Diode. Please
ensure that the correct configuration is selected per your photo diode type as detailed above.
Page 3E-8
OFF THE GENERATOR AND ENSURE THAT ALL CAPACITORS ARE
Rev. D Millenia / Indico 100 Series Service Manual
CPI Canada Inc.
Ch # 740904-07