14 May 2004
Stanford Research Systems have added to their extensive range of signal recovery products with the introduction of the SR240A and SR445A preamplifiers. The two products have almost identical specifications but differ in their physical presentation, the SR240 is a single width NIM module, the SR445A is a standalone laboratory bench instrument.
Both units have four independent channels each with a gain of 5x which may be cascaded to provide up to 624x gain. The rise/fall times of the amplifiers is 1ns, the input noise is a very low 6.4nV/ÖHz and the input and output impedance is 50ohms. The input impedance of channel one of the bench mounted model may be increased to 500ohms by a front panel switch. This can improve the sensitivity to signals from current and charge output devices such as photomultiplier tubes. Additionally, this unit has separate offset adjustments on each channel enabling the user to rapidly null DC errors. Input protection is provided against a ±50v signal for 1µs, recovery time from a 10x overload is 3ns. An output clamp of ±1.6v is installed with an output overload detection of ±1.3v. The input range specified is ±200mV with an output of 1v.
The fast rise time, low noise and excellent DC accuracy of the two amplifiers make them ideal instruments for use with photomultipliers and photodiodes. The SR240A is useful for amplifying small signals to levels that can be processed by other boxcar systems. The SR445A can be used to improve the sensitivity of oscilloscopes, photon counters, boxcar averages, spectrum analysers and other high frequency test equipment.
The Stanford SR240A and SR445A are exclusive distributed in the UK by the company’s UK representative Lambda Photometrics.
For more information contact Wing Ng or Preetesh Mistry at Lambda Photometrics Ltd on: 01582 764334 or email