Capacitance Measurements
- Measuring equipment and measurement procedure
  - Keysight U1733C
  - Keysight N9917A
- Detector C for low frequencies
  - S11 measurements

Capacitance Measurements

The goal is to measure the capacitance of the detectors which are in use in the high energy beam lines as a fiction of frequency. This information can be used in to simulate detector response and for diagnostics of the detector health. For instance defect cables can be discovered by controlling the detector capacitance.

Measuring equipment and measurement procedure

Keysight U1733C, Handheld LCR Meter. Used to determine C at 100 Hz, 120 Hz, 1 kHz, 10 kHz, 100 kHz
Keysight N9917A network-analyser. S11 measured at frequency larger than 30 kHz. The maximum measurement frequency is set automatically by selecting maximum cable length of 1 m in the TDR measurements, or to 10 MHz when S11 is recorded.

Keysight U1733C

Using the ZLCR button select C with serial resistance.
Select the measurement frequency with the Freq. button
Lave the rage to Auto
After connecting the measurement cable select Δ Null. Hence, a relative measurement is done

Keysight N9917A

In the cable menu: More → TDR ( Ohm )
Setup: Start = 0 m, Stop = 1m
Out power: High
VF = 0.7

For S11 measurement, select NA and set Start F = 30 kHz, Stop F = 10 MHz

For all measurements perform quick calibration with SMA open and 50 Ohm load from the Nano-VNA set

Detector C for low frequencies

Detector	F [kHz]	C [pF]	Θ [deg]
Ref.Cal. L=65cm	0.100	66.1	-89.0
	0.120	67.2	-89.7
	1	67.1	-89.8
	10	67.0	-80.0
	100	66.9	-89.1
FAIR-SEM	0.100	124.8	-89.8
	0.120	124.8	-89.8
	1	124.5	-89.8
	10	124.1	-80.0
	100	123.8	-89.2
FAIR-IC	0.100	228
	0.120	227
	1	226
	10	225.8
	100	223.3
BLM-IC	0.100	428.5
	0.120	428.5
	1	428.7
	10	427.9
	100	426.8
BLM-PC	1	8

S11 measurements

S11 FAIR-SEM