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SR400Dual Channel Gated Photon Counter

SR400Dual Channel Gated Photon Counter
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SR400Dual Channel Gated Photon Counter - 1

Photon Counters SR400 — Gated photon counter (2-channel) SR400 Gated Photon Counter The SR400 Dual-Channel Gated Photon Counter offers a convenient, integrated approach to photon counting that avoids the complexity and expense of older counting systems. No longer is it necessary to mix and match amplifiers, discriminators, gate generators and counters. The SR400 combines all these modules into a single, integrated, microprocessor-controlled instrument. Complex measurement tasks such as background subtraction, synchronous detection, source compensation, and pile-up correction can all be performed easily with the SR400. · Two independent counting channels · Count rates to 200 MHz · 5 ns pulse-pair resolution · Gated and continuous modes · Gate scanning for time-resolved counting · Built-in discriminators The SR400 has two independent channels that can count at rates up to 200 MHz. Different counting modes allow you to count for a fixed amount of time, until a certain number of counts have been received, or for a fixed number of triggers. Each counting channel has its own gate generator which provides counting gates as short as 5 ns or as long as 1 s. The gates can be set in a fixed position relative to the trigger signal, or scanned to measure lifetimes or recover timevarying waveforms. · Gate and discriminator outputs · GPIB and RS-232 interfaces The actual inputs to the counters can be viewed as NIM level pulses from the discriminator outputs on the front panel. The discriminated pulses are negative going from 0 to –0.7 V. The DISC outputs are very useful when adjusting discriminator thresholds or gate timing. Stanford Research Systems

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SR400Dual Channel Gated Photon Counter - 2

SR400 Gated Photon Counter counting is disabled and data may be transferred or external parameters may be changed. The dwell output provides a TTL signal which is high during the dwell time. This can be convenient when interfacing other instruments used in the experiment. Signal Inputs and Discriminators Both analog signal inputs (A and B) are internally terminated into 50 Ω. The inputs accept signals between ±300 mV and are protected to ±5 VDC. Each input is followed by a DC to 300 MHz amplifier, allowing detection of pulses as small as 10 mV. If additional sensitivity is required, a...

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SR400Dual Channel Gated Photon Counter - 3

The stop key terminates the current count period and pauses the scan. If scanning, gates and disc levels are held at their current values. Pressing the stop key while in a paused condition will reset the scan, and all scanned parameters will return to their start values. Pressing the start key while paused resumes the scan by starting the next count period. Signal Inputs Bandwidth Input impedance Linear range Input protection Overload recovery The dwell time may also be set to external. In this mode, count periods begin with the start key or external start input (TTL rising edge). Count...

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