
The AH501D has been especially designed as the turnkey solution for photon BPM systems as diamond detectors, ion chambers and blade gap-monitors.
The AH501D is a 4-channel low noise and fast sampling rate bipolar picoammeter with an integrated bias voltage source and voltage analog monitors. It is composed by a transimpedance input stage for current sensing combined with a buffered output voltage circuit that allows users to monitor the input current behavior and level with a simple oscilloscope or a multimeter.
This device performs bipolar current measurements from ±2.5 nA (with a resolution of 300 aA) up to ±2.5 mA (resolution of 300 pA) with a minimum sampling period of 38.4 µs (equivalent to 26 kHz, for 1 channel and a 16-bit resolution).
The simultaneous sampling of the 4 independent channels makes this instrument ideal for beam position monitoring applications or multichannel acquisition.

Extremely low-noise bias source (up to 30V) makes it the perfect fit for low-voltage biasing application.
The presence of an internal low-noise (0.0005% of full scale) voltage source, ranging from 0 to 30V, makes it extremely useful when using blade gap-monitors or diamond detectors needing a bias potential in order to increase the signal intensity and thus the signal-to-noise ratio. This built-in bias voltage source signal is available on a BNC connector and can also be set to a high-impedance state.
The AH501D is housed in a light and extremely compact box that can be placed close to the signal sources in order to reduce cable lengths and to minimize possible noise pick-up on the biasing and measuring signal paths. Low temperature drifts, good linearity and very low noise levels enable users to perform very high precision current measurements.
The AH501D picoammeter has an Ethernet 10/100 communication interface (TCP-IP and UDP) that allows easy instrument control with several programming languages and operating systems.
The AH501D has an external TRIGGER/GATE input signal on a coaxial LEMO connector in order to synchronize the acquisition of the picoammeter with external events - e.g. laser triggering. Furthermore, as for the other members of the CAEN ELS picoammeter family, digital samples can be transferred either using ASCII format or RAW binary data format for fast data transmission.
- From ± 2.5 nA to ±2.5 mA current full-ranges
- Up to 26 kHz sampling frequency
- 24-bit A/D conversion
- Analog voltage monitors
- Low-noise bias voltage source (up to 30V)
- 120 fA full-scale range noise (typical)
- 4-channel simultaneous sampling
- Linear low-noise dual power supply PS2209 included
- Standard Ethernet 10/100 communication interface