IPC Report: Chapter 5; 5.3.5

5.3.5 High Voltage Calibration

Purpose

To calibrate the High Voltage electronics chains by determining the relationships between the following quantities: 1) Number of pulses sent to the HVPSs ("High Voltage Setting") and the voltage at the input to the E-box ("Input Voltage"), 2) Number of pulses sent to the HVPSs and the voltage at the Anode, Anti, or Cathode wire plane ("Feedthrough Voltage"), 3) The Input Voltage and the reading of the "HVPS monitor" (see section 3.2), and 4) The Feedthrough Voltage and the reading of the "E-box monitor" (see section 3.3.2). These relationships are found for the Anode, Anti, and Cathode HVPSs.

Table 13: Crosstalk with the E-box disconnected from the IPC. All numbers are given as a % of 4.0 V. A negative entry indicates that the crosstalk signal is inverted relative to the polarity of a signal for an x-ray event.

Pulsed Channel	Slow Anode	Backanti	Sideanti	Wedge	Strip	Zee	Fast Anode
LE1
Slow Anode	100.0	1.5	0.2	0.2	0.2	0.2	113.5
Backanti	-0.3	100.0	0.1	0.2	0.1	0.1	-1.8
Sideanti	-0.3	0.1	100.0	0.1	-0.1	-0.1	0.8
Wedge	0.3	0.3	3.5	100.0	0.1	-0.1	1.2
Strip	0.1	0.1	-0.1	-0.1	100.0	0.1	0.5
Zee	0.2	0.2	-0.1	0.9	2.2	100.0	0.9
LE2
Slow Anode	100.0	0.5	0.1	0.1	0.1	0.1	117.0
Backanti	-0.1	100.0	0.1	0.1	0.1	0.1	-1.6
Sideanti	-0.2	0.06	100.0	0.04	-0.04	-0.04	0.3
Wedge	0.1	0.1	1.5	100.0	-0.04	-0.04	0.5
Strip	0.1	0.1	-0.1	-0.1	100.0	0.3	0.5
Zee	0.04	0.04	-0.1	0.9	1.2	100.0	0.3
HE1
Slow Anode	100.0	0.5	0.1	0.1	0.1	0.1	49.5
Backanti	0.1	100.0	0.1	0.1	0.1	0.1	0.1
Sideanti	0.1	0.1	100.0	-0.1	-0.1	-0.1	0.2
Wedge	0.1	0.1	1.4	100.0	0.1	0.1	0.3
Strip	0.1	-0.1	0.1	0.1	100.0	0.1	0.3
Zee	0.1	0.2	-0.1	0.3	-0.1	100.0	0.3
HE2
Slow Anode	100.0	0.6	0.3	0.3	0.3	0.3	110.5
Backanti	0.3	100.0	0.3	0.3	0.3	0.3	0.5
Sideanti	1.1	0.2	100.0	0.3	0.3	0.3	-1.2
Wedge	0.2	0.2	1.3	100.0	0.3	0.3	0.5
Strip	0.2	0.2	0.2	0.2	100.0	0.5	not measured
Zee	0.3	0.3	0.3	0.5	1.3	100.0	not measured

Table 14: Crosstalk with the E-box connected to the IPC. All numbers are given as a % of 4.0 V. A negative entry indicates that the crosstalk signal is inverted relative to the polarity of a signal for an x-ray event.

Pulsed Channel	Slow Anode	Backanti	Sideanti	Wedge	Strip	Zee	Fast Anode
LE1
Slow Anode	100.0	0.9	-0.9	-0.5	-0.5	-1.0	95.5
Backanti	0.3	100.0	-0.4	-0.3	-0.3	-0.6	-0.6
Sideanti	-1.3	-0.4	100.0	0.4	0.4	0.3	-4.4
Wedge	-0.1	-0.5	2.6	100.0	0.5	3.0	-0.8
Strip	-1.9	-0.8	0.2	0.6	100.0	3.5	-1.0
Zee	-0.2	-1.2	0.1	3.9	4.4	100.0	-2.4
LE2
Slow Anode	100.0	0.8	-0.9	-0.5	-0.5	-1.0	93.5
Backanti	0.4	100.0	-0.5	-0.3	-0.4	-0.7	2.0
Sideanti	-1.0	-0.5	100.0	0.4	0.5	0.3	-4.0
Wedge	-0.04	-0.04	2.3	100.0	0.5	3.1	-0.4
Strip	-6.2	-0.2	0.4	0.7	100.0	3.8	-6.1
Zee	-0.2	-0.2	-0.04	3.9	4.5	100.0	-0.7
HE1
Slow Anode	100.0	1.0	-0.9	-0.4	-0.5	-0.9	142.5
Backanti	0.3	100.0	-0.5	-0.3	-0.3	-0.6	2.9
Sideanti	-0.6	-0.6	100.0	0.4	0.5	0.3	-5.5
Wedge	0.2	0.1	2.8	100.0	0.4	3.0	0.3
Strip	-1.9	-0.1	0.2	0.5	100.0	3.0	-2.9
Zee	-0.1	-0.1	-0.06	3.3	3.1	100.0	-1.0
HE2
Slow Anode	100.0	-0.2	0.2	0.2	0.2	0.2	94.1
Backanti	-0.2	100.0	0.2	0.2	0.2	0.2	-1.6
Sideanti	0.1	0.1	100.0	1.5	1.3	1.2	1.1
Wedge	0.1	0.1	0.3	100.0	0.7	0.6	0.3
Strip	0.04	0.04	0.4	0.7	100.0	0.7	0.3
Zee	0.04	0.04	0.5	0.8	0.5	100.0	0.4

Testing Setup and Procedure

As the High Voltage Setting is varied, the Input and Feedthrough voltages are measured with electrostatic voltmeters (ESVMs) and the E-box and HVPS monitor voltages are measured with DVMs.

Analysis and Results

For each of the four relationships discussed above, a least squares linear fit is calculated to the data. The fit parameters (slopes and offsets) for the four relationships are given in Tables 15, 16, and 17 for the Anode, Anti, and Cathode HVPSs for each IPC. In each case, the "offset" is the intercept of the vertical axis. The axis assignments for the four cases follow:

Horizontal Axis

Vertical Axis

Location of Fit Parameters

High Voltage Setting

Input Voltage

Table 15

High Voltage Setting

Feedthrough Voltage

Table 15

Input Voltage

HVPS Monitor Reading

Table 16

Feedthrough Voltage

E-Box Monitor Reading

Table 17

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