Stanford Research SR400 Photon Counter, nice condition. Sold with a warranty!

Web Information

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.

Counters

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 providing 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 time-varying waveforms.

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.

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 remote preamplifier (like the SR445A) can be used.

Discriminators are provided for each channel with a selectable threshold from -300 mV to +300 mV in 0.2 mV steps. Pulse-pair resolution is 5 ns, and pulses of either polarity may be detected. Each threshold may be programmed to scan in either direction with selectable step size. This can provide a pulse height analysis (PHA) output and is useful for choosing photomultiplier tube bias or discriminator levels.

Count Periods

The SR400 may be programmed to cycle from 1 to 2000 count periods in a single scan. At the end of the programmed scan, the counters may be stopped or the scan may be restarted. Consecutive count periods are separated by a "Dwell Time" which can be set from 2 ms to 60 s. During the Dwell Time, 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 for interfacing other instruments used in the experiment.

Outputs

The front panel can display counts up to 109. Results from both counters can be displayed individually or combined as A-B or A+B. A front-panel D/A output provides an analog signal proportional to A, B, A-B, or A+B, depending on the counting mode. The scale may be logarithmic (1V/decade) or linear.

Computer Interfaces

Built-in RS-232 and GPIB interfaces provide a convenient means of controlling the instrument and retrieving data. While the SR400 is scanning, each of the count values for the A and B counters are stored in a 2000 point internal buffer. This buffer can be transferred on a point-by-point basis, or dumped all at once through either interface.

Condition

Used. Good condition.

Includes

• Stanford Research SR400 Photon Counter
  
• Power cord

SHLR

Warranty

30 Day warranty. We pledge to offer the best service and warranty to all of our customers!  We are extending a 30 Day warranty on this item. This is our way of saying thank you for allowing us to serve you.

Certification

This is a genuine product from this manufacturer.

Disclaimer

Regardless of the origin of the equipment, documentation provided or identification appearing upon the equipment, the equipment described and offered here is in no way certified for, recommended for, or offered for any specific use. The purchaser agrees that the seller shall not be held responsible or liable for any injuries or damages, whether incidental or consequential, associated in any way with the equipment. The purchaser, by bidding on this equipment, indicates their acknowledgment of, and agreement to the terms of this disclaimer. it is the purchaser's responsibility to have the item inspected and certified by a qualified professional before use!