575A Amplifier

Specifications

PERFORMANCE

Gain Range  Continuously adjustable from 5 to 1250.

Pulse Shape  Semi-Gaussian on all ranges with peaking time equal to 2.2t, 50% pulse width equal to 3.3t, and pulse width at 0.1% level equal to 4.0 times the peaking time. Bipolar crossover = 1.5 t

Integral Nonlinearity  For 1.5-µs shaping time, <±0.05%.

Noise  <5 µV rms referred to the input using 3-µs unipolar shaping; <7 µV using 1.5-µs shaping; both for a gain ³100.

Temperature Instability
Gain  £±0.0075%/°C, 0 to 50°C.
DC Level  £±30 µV/°C, 0 to 50°C.

Bipolar Crossover Walk  £±5 ns at 0.5 µs for 50:1 dynamic range, including contribution of an ORTEC Model 552 Single-Channel Analyzer.

Overload Recovery  Recovers to within 2% of rated output from X300 overload in 2.5 nonoverloaded pulse widths using maximum gain for unipolar output. Same recovery from X500 overload for bipolar.

Restorer  Gated active baseline stabilizer with automatic threshold circuit to provide the threshold level as a function of signal noise to the baseline restorer discriminator.

Spectrum Broadening Typically <10% FWHM for a ⁶⁰Co 1.33-MeV gamma line at 85% of full scale for an incoming count rate of 1,000 to 50,000 counts/s (Unipolar output, 1.5-µs shaping).

Spectrum Shift* Peak position shifts typically <0.02% for a ⁶⁰Co 1.33-MeV gamma line at 85% of full scale measured from 1,000 to 50,000 counts/s (Unipolar output, 1.5-µs shaping).
*These count-rate specifications were measured with a 10% HPGe detector. Detectors with a large number of slow rise-time signals will most likely give poorer results.

ELECTRICAL AND MECHANICAL

Power Required  +12 V, 55 mA; -24 V, 40 mA; +12 V, 70 mA; -12 V, 75 mA.

Weight
Net  1.5 kg (3.3 lb.)
Shipping  3.1 kg (7.0 lb.)

Dimensions  Standard single-width NIM module 3.43 x 22.13 cm (1.35 x 8.714 in.) per DOE/ER-0457T.

CONTROLS

FINE GAIN  10-turn precision potentiometer with graduated dial for continuously variable direct-reading gain factor of X2.5 to X12.5.

COARSE GAIN  6-position switch selects feedback resistors for gain factors of 2, 4, 10, 20, 40, and 100.

SHAPING TIME  3-position printed wiring board (PWB) jumpers, easily accessible through side panel,  select time constants for active pulse-shaping filter network from 0.5, 1.5, and 3 µs.

POS/NEG  Toggle switch selects either Pos or Neg input pulse polarity.

PZ ADJ  Screwdriver adjustable potentiometer to set the pole-zero cancellation to compensate input decay times from 30 µs to infinity.

INPUTS

BNC front- and rear-panel connectors accept either positive or negative pulses with rise times of 10 to 650 ns and decay times of 30 µs to infinity, Z_in @ 1000 W dc-coupled; linear maximum 2 V; absolute maximum 20 V.

OUTPUTS

UNI  Front-panel BNC connector with Z_o <1 W and rear-panel connector with Z_o = 93 W, short-circuit proof; full-scale linear range of 0 to +10 V; active filter shaped; dc-restored; dc-level adjustable to ±15 mV.

BI  Front-panel BNC connector with Z_o <1 W and rear-panel connector with Z_o = 93 W, short circuit proof; positive lobe leading and full-scale linear range of 0 to +10 V; active filter shaped.

PREAMP POWER  Rear-panel standard ORTEC power connector. Amphenol 17-10090, mates with captive and noncaptive power cords on all ORTEC preamplifiers

ORDERING INFORMATION