Photon counting is the fundamental method for extracting the maximum information from a weak light signal. Coupling an amplifier-descriminator to a photomultiplier achieves this.

An amplifier-discriminator combines a fast amplifier and a fixed-threshold discriminator with an overall sensitivity of approximately one millivolt. With the gain of the photomultiplier optimised, photon counting with a high signal to noise ratio and stability can be achieved up to count rates of 100 MHz.

ET Enterprises offers a range of amplifier-discriminators with output logic levels compatible with commercially available counters. Please refer to the section on the CT2 counter/timer module. A cable, LEADAD6CT2, is available to connect the AD6 to the CT2, and powers the AD6.

The range is summarised in the table below.

Amplifier Descriminator Selection Guide
type input
impedance
ohms
input
threshold
mV
pulse pair
resolution
(ns)
output
pulse
power
requirements
AD1 50 -1 100 ECL +5V, 25mA 
-5V, 100mA
AD2 50 -0.5 to -2.5 25, 40, 80* ECL +5V, 25mA 
-5V, 100mA
AD3 50 -2 to -5 10 to 100 ECL -5V, 65mA
AD6 50 -2 24 TTL** +5V, 10mA
AD7 50 -2 to -5 24 TTL** +5V, 10mA
AD8 50 -2 25 TTL +5V, 10mA

 

* preset with external links, please specify when ordering, easily reset
** not suitbale for use with fast counters

Amplifier-discriminators are available as modules in metal cases with BNC input connector and 9-way D-connector output and LV power connection, view an outline drawing here. The AD7, which is pcb mounting, is supplied in a metal case. View an outline drawing here. Examples are also shown in the photograph on this page. They can also be incorporated into housings; please refer to the section on housings.

Read about amplifier-discriminator options here.

© ET Enterprises Limited 2011-2015
ET Enterprises is a trading name of ET Enterprises Limited. Registered in England & Wales, company number 06081468.