474 Timing Amplifier

• Timing with germanium detectors
• Energy spectroscopy at ultra-high count rates
• Selectable filter for pulse shaping
• Signal-to-noise ratio optimization
• Continuously adjustable gain X2 to X250
• Pole-zero cancellation
• DC-coupling

The Model 474 Timing Filter Amplifier is especially designed to shape pulses and permit optimizing the signal-to-noise ratio for timing measurements. The Model 474 is particularly suited for use with an ORTEC Constant-Fraction Timing Discriminator in timing applications with germanium or silicon charged-particle detectors (Fig. 1). It derives its input signal directly from the preamplifier output. The timing spectrum in Fig. 2 illustrates the performance obtainable with the Model 474 shaping the germanium detector pulses before they are furnished to the discriminator. Tables 1 and 2 give typical performance data for various ORTEC germanium detectors.

The fast rise time, high output drive, and high gain capabilities of the Model 474 make it useful for other applications, such as timing with systems utilizing low-gain photomultiplier tubes. In addition, the pole-zero cancellation network, the dc-coupling, and the time-invariant baseline restorer permit energy spectroscopy with scintillation detectors and Si charged-partical detectors at ultra-high count rates.

A wide variety of input pulse shapes can be filtered as required for optimum signal processing. The Model 474 combines continuously adjustable gain (X2 to X250) with separately selectable Integrate (t_i) and Differentiate (t_d) time constants for proper pulse shaping, making this unit and important asset for time measurement.

ORDERING INFORMATION