Advanced Measurement Technology ORTEC A-576 A-PAD, Operating And Service Manual

2

2.  SPECIFICATIONS 

2.1.  PERFORMANCE 

ENERGY RANGE  Six positions on the front-panel

switch for selecting the desired energy range (see

DETECTOR AND ELECTRONIC NOISE  <25 keV

PERFORMANCE).

FWHM when used with ORTEC R Series, 300 mm

2

and 450 mm  charged-particle detectors, and <35 keV

E BIAS  15-turn potentiometer on the front panel

2

for 600 mm  and 900 mm  R Series charged-particle

permits screwdriver adjustment of the energy output

2

2

detectors when connection of the Model A-576 to the

bias point to be varied by ±10% for ease of setup with

detector is made with <2 ft of RG-62A/U cable.

the data acquisition system.

System noise is dependent on detector capacitance
plus cable capacitance and leakage current. Electronic

E  15-turn potentiometer on the front panel permits

noise is typically 5 keV with a slope of 25 eV/pF silicon

screwdriver adjustment of the maximum energy output

equivalent (based on 

 = 3.6 eV and t = 0.5 µs

range to be varied from 7.75 to 10.25 V for ease of

(internal amplifier).

setup with the data acquisition system. 

PULSE SHAPING  Internal 0.5-µs active filter semi-

TEST PULSER  PWB jumper (J2) allows selection of

Gaussian pulse shaping amplifier provides a pulse that

internal pulser energies of 5 MeV, 6 MeV, or 7 MeV.

is stretched prior to being output through the Bias
Amplifier to give a 4-µs-wide positive output pulse. 

INPUT/BIAS POLARITY  PWB jumpers allow

ENERGY RANGES  3 TO 8 MeV, 4 to 7 MeV, 3 to 5

polarity. Negative for ORTEC Surface Barrier or Ion-

MeV, 4 to 6 MeV, 5 to 7 MeV, 6 to 8 MeV.

Implanted Ruggedized detectors, or positive for

conventional detectors. (Shipped in Negative position.)

CALIBRATED TEST PULSER    Equivalent  Energy 
5  MeV, 6 MeV, or 7 MeV. (Shipped at 5 MeV). Rate is 
100 Hz. 

2.3.  INPUT 

DETECTOR BIAS VOLTAGE   Continuously variable

PREAMP IN   Front- and rear-panel BNCs accept an

over range of 0 to 100 V. Polarity selectable with

input signal from semiconductor charged-particle

printed wiring board (PWB) jumper shipped in negative

detectors. Either RG-62A/U or RG-71A/U cable is

position (appropriate for ORTEC R Series detectors).

recommended to minimize excess capacitance and

Shipped set to 100 V.

hence noise. 

2.2.  CONTROLS 

2.4.  OUTPUTS

 
TEST/BIAS/OFF   Front-panel, three-position toggle

ENERGY  Front- and rear-panel BNC connectors

switch controls both the detector bias voltage and the

provides a  positive stretched pulse  from 7.75 to

test pulser. Front-panel LED is illuminated when the

10.25 V maximum, depending on the setting of the 

E

bias voltage is on. 

gain control corresponding to an energy range

DET BIAS ADJ  Front-panel potentiometer for

4 µs; Z  = 100 

6

; dc-coupled.

controlling the bias voltage applied to the detector.
Continuously variable from 0 to ±100 V. 
 

selection of either positive or negative detector voltage

selected  on the  front-panel switch.   Pulse width = 

0