Mech-Tronics 404 FET Preamplifier

MODEL 404 FET PREAMPLIFIER
  • Noise - 3.5 KeV @ 10 pf (Si)
  • Noise Slope: .035 KeV/pf (Si)
  • 35 Nsec. Rise Time

GENERAL DESCRIPTION

The Model 404 FET Preamplifier features a low noise FET transistor input circuit and is intended for room temperature silicon surface barrier detectors and low noise x-ray proportional counters. The Model 404 is inverting, highly linear and has fast rise time characteristics.

The preamplifier decay time constant is 50 µsec., matching the pole-zero cancelled 1st differentiator in Mech-Tronics' 500 Series main amplifiers. Operating power is derived through the single BNC signal interconnection between main amplifier and preamplifier.

COMPATIBILITY

The Model 404 FET is ideally suited for application with the range of Mech-Tronics amplifiers.

 

SPECIFICATIONS

 

INPUT

 

Polarity:

Either positive or negative accepted.

 

 

Impedance:

Effectively zero ohms.

 

 

OUTPUT

 

Polarity:

Inversion of the input.

 

 

Impedance:

50 ohms.

 

 

Test Input:

Accepts output from pulse generator through a 2.2 pf NPO Capacitor, useful in system calibration.

 

 

PERFORMANCE

 

Noise:

0.5 x 10-16 coulombs rms or 3.5 KEV FWHM (Si) with 10 pf input shunt capacitance and 0.8µsec. main amplifier clip and integration time constants.

 

 

Noise Slope:

0.035 KEV/pf (Si)

 

 

Integral Linearity:

Within 0.1% to ±2 volts

 

 

Stability:

.005%/°C

 

 

Conversion Gain:

450 millivolts per picocoulomb, 20 millivolts per MEV (Si)

 

 

Open Loop Gain:

>5,000

 

 

Rise Time:

35 nsec.

 

 

High Voltage:

Accepts 2800 volts maximum for detector

 

 

High Voltage Filter:

1 megohm, 0.0005µf.

 

 

Blocking Capacitor:

0.005µf.

 

 

Saturation Level:

±4 volts open circuit measurement

 

 

CONNECTORS

 

Detector:

Accepts input pulses from detector and furnishes high voltage out to the detector. Gremar No. 6317

 

 

High Voltage Input:

Accepts high voltage to be furnished to detector. Gremar No. 6317

 

 

Output:

Connects output pulses to main amplifier, and accepts preamplifier operating voltage from amplifier, BNC type UG1094/U.

 

 

Test Input:

Pulse generator input connector. BNC type UG1094/U.

 

 

 

 

Power Requirements:

-24 volts @ 10 ma derived from main amplifier

 

 

Cable Supplied:

72 inch Signal Cable (BNC to BNC) Part No. 186300-72.

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