3.4 Dose1/Dose2 Calibration - CPI Indico 100 Series Service And Installation Manual

CPI Canada Inc.
3E.3.3 I.I. Input Dose Calibration (Cont)
15.
16.
17.
3E.3.4 Dose1/Dose2 Calibration
Use these steps to calibrate dose 1 and dose 2.
Step
1.
2.
3.
4.
5.
6.
Millenia / Indico 100 Series Service Manual
Adjust the PMT high voltage using R10 (refer to figure 3E-6) on the AEC interface
board while pressing the fluoro footswitch such that the PMT current is 20 ± 5 uA at
the desired I.I. input dose. This corresponds to a voltage of 2.00 ± 0.50 VDC for a
100K resistor if using the voltmeter method in the above step. The high voltage should
be approximately -750 VDC at this point.
The PMT high voltage is adjusted to yield the PMT current noted in this step. The
approximate value of PMT voltage is stated for reference only. The PMT voltage does
not normally need to be measured in this step, however, if it is desired to do so for
troubleshooting purposes please note the following:
USE TP5 ONLY ON THE AEC INTERFACE BOARD FOR THE HV METER
GROUND WHEN MEASURING PMT HIGH VOLTAGE. CONNECT THE GROUND
FIRST BEFORE MEASURING THE HIGH VOLTAGE. DO NOT ATTEMPT TO
MEASURE THIS WITHOUT A SUITABLE METER.
Disconnect the meter (and resistor if applicable) that was was connected in step 9.
Reconnect the PMT signal lead if required.
Initiate fluoro operation and measure the input dose to the I.I. If this value is not as
desired adjust the NOMINAL DOSE using the + or - buttons as required. Record this
value in step 1 of 3E.3.4.
Action
Before continuing, record the NOMINAL
DOSE value as determined in the previous
section.
Record the desired dose 1 and dose 2
input values.
Initiate fluoro operation and measure the
input dose to the I.I. Adjust to the desired
dose 1 value by altering the NOMINAL
DOSE value as required using the + or -
buttons.
When the desired dose 1 value has been
achieved, enter the new NOMINAL DOSE
value in the DOSE 1 location using the +
or - buttons.
Initiate fluoro operation and measure the
input dose to the I.I. Adjust to the desired
dose 2 value by altering the NOMINAL
DOSE value as required using the + or -
buttons.
When the desired dose 2 value has been
achieved, enter the new NOMINAL DOSE
value in the DOSE 2 location using the +
or - buttons.
Nominal Dose (cal value): _______
Desired dose values:
Dose 1:______________ mR/Min
Dose 2:______________ mR/Min
Ch # 740904-07 Rev. D
3E
ABS Calibration
Result
Page 3E-21