FC20 Voltage Divider

The FC20 is a fast, frequency-compensated high voltage divider and was developed at the University of Münster as experimental infrastructure for Dielectronic Recombination experiments at the CRYRING@ESR ElectronCooler.

Specifications / Instructions

An overview of the technical specifications of the device and instructions for operation and calibration can be found in the FC20 specification document.

The readout of the divider is accomplished using a 7.5 digit Keithley DMM7510 multimeter, serial no.: 04614483, reachable under: atpdev010.gsi.de, IP: 140.181.97.183 .

Cailbration history

The scale factors of the FC20 were measured repeatedly against a Fluke 752A reference divider and are listed in the table below together with the DVM offsets and gain values required to accurately determine the input voltages measured with the device according to the formula

Date	DVM	DVM Offset [V]	DVM Gain	94:1	1027:1	1961:1
2023-11-25	Keysight 34465A	(7.8 ± 1.3)e-7	1.00000259(15)	94.344040(7)	1027.77736(16)
2023-12-04	Keysight 34465A	( 7 ± 6)e-7	1.00000358(18)		1027.7761(6)
2023-12-07	Keysight 34465A	( 7 ± 6)e-7	1.00000358(18)	94.344104(10)
2024-01-18	Keysight 34465A	(0.4 ± 1.5)e-7	1.00000395(16)	94.344037 (11)	1027.77736 (20)
2024-03-06	Keithley DMM7510	(1.26 ± 0.28)e-6	1.00000064(16)		1027.77002(32)
2024-03-18	Keithley DMM7510	(0.65 ± 0.35)e-6	1.00000082(18)		1027.7694 (4)

The error bars given in the table are statistical only. The main sources of systematic uncertainty are:

• A 2 ppm uncertainty on the value of the Fluke 732A 10V reference source used (it was calibrated against another 10V reference which had a 1 year old calibration. According to the datasheet, these sources can have drifts of up to 2 ppm/year).
• The Fluke 752A precision divider used as a reference has, if correctly tuned, an uncertainty of 0.5 ppm of its 1:100 scale factor. Due to the noisy environment in the CRYRING a precise tuning was difficult and we estimate an uncertainty of 2 ppm for the divider in our measurements.
• The DVM offsets and gains quoted in the table are subject to drifts over time. The remaining acccuracy after a given time interval is specified in the corresponding datasheets of the devices.
• We should conservatively take into account a drift of the measured scale factors after calibration of up to 2 ppm over 10 days.

As these systematic effects are independent, they may be added in quadrature.

See also

• ArnoldHV
• G35VoltageDivider
• MachineSignals
• Electron Cooler