474 Timing Filter Amplifier

Specifications

PERFORMANCE

Input Amplitude Range  0 to ±1 V signal, 0 to ±5 V dc offset; maximum input ±5 V total.

Output Amplitude Range  0 to ±5 V with a 50-W load.

Noise  For maximum gain, rms noise referred to the input is £10 µV with t_i = t_d = 200 ns or £50 µV with filter out; measured using a Hewlett-Packard 3400A true rms meter.

Rise Time  £10 ns with filter out  or ~2.2 t_i for other selections.

Nonlinearity  £±0.05% at midband frequency over ±5 V range.

Temperature Instability
DC Level  £±25µV/°C referred to the output.
Gain  £±0.06%/°C.
Specifications over 0 to 50°C range.

ELECTRICAL AND MECHANICAL

Power Required  +24 V, 65 mA; -24 V, 45 mA; +12 V, 160 mA; -12 V, 180 mA.

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

Weight
Net  1.0 kg (2.4 lb)
Shipping  2.5 kg (5.4 lb)

CONTROLS

COARSE GAIN  Front-panel 6-position switch for selection of X1, X2, X4, X6, X10, or X20.

FINE GAIN  Front-panel single-turn potentiometer, continuous from X2 to X12.5.

PZ ADJ  Front-panel screwdriver adjustment to compensate for the preamplifier decay time constant.

Time Constant  Two 6-position switched on front panel:
INTEGRATE  RC time constants: OUT (equivalent to 4 ns), 20, 50, 100, 200, and 500 ns.
DIFF  RC time constants: OUT (equivalent to 0.2 ms), 20, 50, 100, 200, and 500 ns.
NOTE:  With Differentiate and Integrate in the OUT position, the passband is 1 kHz to 35 MHz.

NON INV/INV  Selects inversion or non-inversion of the input signal.

INPUT

Positive or negative polarity selectable by front-panel switch; amplitude 0 to ±1 V; protected to ±6 V dc and to ±100 V at 10% duty factor integrated over 1 s; impedance 100 W, dc-coupled; front-panel BNC connector. Accepts a ±5 V dc offset, maximum input (signal plus offset) limited to ±5 V.

OUTPUTS

OUTPUT  Front-panel BNC connector.
Amplitude 0 to ±5 V; rise time £10 ns for filter out (2.2 t_i for other filter selections). Impedance <1 W, dc-coupled.

Preamplifier Power  Rear-panel standard ORTEC power connector, Amphenol 17-10090.

Table 1.  Timing Resolution for Various Sizes of Germanium Detectors Using ²²Na.

Table 2. Timing Resolution for Large Germanium Detectors Using 583 CFDD/SCA, 474 TFA, and ⁶⁰Co.

ORDERING INFORMATION

Fig. 1  Simplified Timing System.

Fig. 2  Timing Spectrum for a Narrow Synamic Range Using a Germanium Detector. (Resolution values are given in Table 1.)

22Na
Start:  KL236 (1x1), RCA 8575 Photomultiplier Tube
Stop:  Ge Coax, 12.5%, 62.3 cc
1.1:1 Dynamic Range
473A Discriminator