High Voltage Module Options for Pyramid Products

High Voltage Bias

Pyramid electrometers intended to read signals from sensor systems can include a high voltage bias supply. This can be installed at manufacture or added later as an upgrade. Current flagships such as the FX4 and IX256 ship with integrated HV bias options; many earlier F- and I-series models use the same external-bias module family. HV bias is used for:

• Biasing ionization chambers and proportional chambers
• Biasing diodes
• Providing secondary electron suppression in Faraday collectors
• Providing the voltage gradient in electron multipliers and photomultipliers
• Biasing a sensing element so that secondary electrons are driven from it

For HV accuracy and calibration checks, see Calibration of Current and Charge Measuring Devices. Topology choice (F vs I) is covered in Choosing F or I Devices for Current Measurement.

Bias Configurations

There are two bias configurations: external bias and signal bias. All relevant products allow external bias supplies. Only the I400 also allows signal bias. The distinction is whether the signal is referenced to local ground, or measured at a voltage different from local ground. Two ionization chamber configurations illustrate the difference.

Using External Bias

With external bias, the detector electrode is driven by a separate HV output and the electrometer measures current (or charge) at local ground.

Using Signal Bias

With signal bias, the measurement node itself sits at high voltage relative to local ground. This configuration is available on the I400 only.

Bias Module Types

All bias modules are rated for one watt output power. Polarity and maximum voltage must be specified at order. Output voltage is controllable via software over the module range, usefully from about 10% of full rating to full rating.

Current Flagship Options

These newer electrometers are not on the classic matrix below. Use the product page configure options when ordering.

• FX4 (current measurement): integrated detector bias through ±2000 V. Live sales suffixes include -XP20, -XP10, -XP05, -XP02, -XN20, -XN10, and -XN05.
• IX256 (charge measurement): integrated HV supply rated to ±3000 V. Common auxiliary options use the same -XNxx / -XPxx style through ±2000 V (for example -XP20, -XP10, -XP05, -XP02, -XN20, -XN10, -XN05, -XN02). Confirm the exact set on the product page when ordering higher ratings.

Classic Bias Options Matrix

The chart above is the original TN0006 availability matrix for earlier catalog models, including IC101, I200, I404, I400, I3200, I6400, I128, F100, F460, F3200E, and C400. Related F- and I-series families share many of these options. Signal bias (±400 V, suffixes -N04 / -P04) is listed for the I400 only.

Checkmark = available option. Highlighted checkmark = popular option. Sales code suffixes appear under each voltage column (for example -XN10 for −1000 V external bias).

Further Information

Contact us for ordering guidance, upgrades, or questions about fitting HV to a specific electrometer (including products newer than this chart). Cabling and connectors are covered under Accessories.