Service manual

Fig. 1.1. Block Diagram of the 579 Fast-Filter Amplifier.

ORTEC MODEL 579

FAST-FILTER AMPLIFIER

1. DESCRIPTION

The ORTEC Model 579 wideband Fast-Filter

Amplifier with Gated Baseline Restorer is a state-of-

the-art hybrid-circuit instrument (Fig. 1.1). It is

designed to enhance fast-timing measurements by

improving the slope-to-noise ratio and providing

ultra-high count rate spectroscopy capability.

The experimenter will recognize ORTEC's firm

commitment to fulfill the most demanding

experimental needs with quality instrumentation.

Fast (5 ns) rise time (Fig. 1.2), high output drive

(±5 V into 50

), and wide voltage gain range (X0.9

- X500) make the 579 useful for many timing

applications, including those utilizing low-gain

photomultiplier tubes. The 579 is particularly suited

for use with ORTEC Constant Fraction

Discriminators such as the 583,584,934, or 473A in

timing applications with High-Purity Germanium

(HPGe) or Surface Barrier Detectors (Figs. 1.3, 1.4,

and Table 1). Excellent dc and gain stability

(±50

V/°C and ±0.05%/°C respectively) eliminates

the need for a dc-level adjustment (Figs. 1.5 and

1.6), and, to further improve the human interface, a

Busy LED and Busy Output are included to aid in

BLR adjustment and system interfacing.

In addition, the wideband gated baseline restorer

and pole-zero cancellation network permit ultra-high

output counting rates (Fig. 1.7). A wide variety of

pulse filtering is available for improved signal

processing. The 579 combines continuously,

variable gain, independently selectable integration

and differentiation time constants (Figs. 1.8 and

1.9), and cable clipping capability (external cable

delay), making this versatile unit an important asset

for advanced time and energy spectroscopy.