An EPICS module that supports quad electrometers/picoammeters, typically used for photodiode-based x-ray beam position monitors, or split ion chambers. They can also be used for any low-current measurement that requires high speed digital input. There is support for several models:
- The AH401B, AH401D, AH501, AH501C, and AH501D picoammeters originally designed Synchrotron Trieste (elettra) They are sold commercially by CAENels. These devices communicate using TCP/IP over 100 Mbit/s Ethernet or high-speed serial. They provide 4-channel current measurements at up to 1000 Hz (AH401 series) or 6510 Hz (AH501 series).
- The TetrAMM picoammeter from CAENels. This device communicates using TCP/IP over 1 Gbit/s Ethernet. It provides 4-channel current measurements at up to 20000 Hz.
- The NSLS Quad Electrometer (called NSLS_EM in the documentation). This device consists of a 4-channel digital electrometer unit using a current integrator with Ethernet communication. The device provides 4-channel current measurements at up to 2500 Hz. The Sydor SI-EP-B4 is based on this design and is software comptabible.
- The NSLS2 Quad Electrometer (called NSLS2_EM in the documentation). This device consists of a 4-channel digital electrometer unit using a transconductance amplifier and built-in EPICS IOC running this software. The device provides 4-channel current measurements at up to 10,000 Hz. This model is capable of measuring larger currents than the NSLS Quad Electrometer above.
- The Quad Electrometer built by Steve Ross from the APS (called APS_EM in the documentation). This device consists of a 4-channel digital electrometer unit and 2 VME boards. The device provides 2 readings per diode at up to 813 Hz. This device appears to no longer be in use on any APS beamlines, so the support is now deprecated and will be removed in a future release.
Additional information:
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