9307 pico-Timing Discriminator

The pico-TIMING Discriminator accepts analog input pulses with amplitudes ranging from –50 mV to –5 V, and pulse widths from 400 ps to 5 ns FWHM. The amplitude threshold for generating a timing output is adjustable from –25 mV to –1 V with a 10-turn locking dial.

Ultra-fast circuits are incorporated in the pico-TIMING Discriminator to minimize time slewing. As a result, input amplitudes can vary over as much as a 100:1 range with negligible shift in the timing output. This ensures excellent time resolution, even when the signal source produces a wide range of randomly varying signal amplitudes. A front-panel screwdriver adjustment permits fine-tuning the slewing compensation to match the characteristics of a particular detector. An adjacent test point makes it easy to monitor the adjustment with a voltmeter.

Two fast negative NIM outputs provide the flexibility to trigger a time-to-amplitude converter (TAC) while simultaneously driving other instruments. The 500-ns-wide TTL output can be used with instruments that require a positive logic signal, such as counters and ratemeters. A front-panel LED flashes with each output pulse to indicate triggering.

For detectors having rise times less than 1 ns, the ORTEC Model 9306 1-GHz Preamplifier should be used to amplify small signals before presentation to the input of the Model 9307 pico-TIMING Discriminator. For rise times ≥1 ns, the Model VT120 Fast-Timing Preamplifier should be substituted for the Model 9306. The Model 9307 incorporates a compatible, 9-pin D connector on its rear panel to supply power to either preamplifier.

The Model 9306 1-GHz Preamplifier is recommended for amplifying ultra-fast analog signals before presentation to the input of the Model 9307 pico-TIMING Discriminator. These ultra-fast analog signals require the use of 50-ohm coaxial cable with SMA connectors. To preserve the 350-ps rise time of the 9306, the total cable length from the detector to the preamplifier, and from the preamplifier to the 9307 should be <1.7 m. Consult the ordering information for the appropriate SMA cables and adapters.

For detectors having rise times >1 ns, the Model VT120 Fast-Timing Preamplifier should be substituted for the Model 9306. In that case, 50-ohm coaxial cables with BNC connectors can be used. Consult the list below for BNC to SMA adapters, and refer to the Cables and Accessories data sheet for the desired cables.

Performance

Time Slewing (Walk)	<±20 ps shift in the timing output for input signal amplitudes from –150 mV to –1.5 V. (Typically <±50 ps for signal amplitudes from –50 mV to –5 V.) Measured using a 1-ns-wide input pulse with 350-ps rise and fall times.
Pulse Pair Resolution	<10 ns at the fast negative NIM outputs.
Maximum Input/Output Rate	Accepts burst rates up to 100 MHz.
Operating Temperature Range	0 to 50°C.
Threshold Temperature Sensitivity	<±0.1 mV/°C (0 to 50°C).
Transmission Delay Temperature Sensitivity	<±10 ps/°C (0 to 50°C).

Controls and Indicators

Threshold	Front-panel, 10-turn potentiometer with locking dial allows adjustment of the input discriminator threshold from –25 mV to –1 V.
Slewing Compensation	Front-panel, 20-turn, screwdriver fine-tuning to minimize time slewing as a function of input pulse amplitude. Adjustable over a range of approximately ±30 mV. A front-panel test point located next to the potentiometer facilitates monitoring the actual setting. Test point output impedance: 100 Ω.
Output LED	Front-panel LED flashes on each output pulse to indicate active triggering.

  
Inputs

Input

Front-panel SMA connector accepts unipolar input signals with amplitudes in the range of –50 mV to –5 V. Minimum input pulse width: 400 ps (FWHM). Maximum input pulse width: 5 ns (FWHM). Input impedance: 50 Ω. The input is protected to ±5 V.

Outputs

Fast Negative NIM Outputs	Front-panel BNC connectors provide two independent, fast negative NIM output logic  pulses. Output amplitude is nominally –800 mV into a 50-Ω load. Pulse width is nominally 2.5 ns.
TTL Output	Front-panel BNC connector provides a positive TTL pulse, triggered by the fast negative NIM output. The 500-ns width of the TTL pulse is non-updating. Output impedance: <1 Ω, short-circuit protected.
Preamp Power	Rear-panel, 9-pin D connector provides ±12-V and ±24-V power for the ORTEC Model 9306 1-GHz Preamplifier, the Model VT120 Fast-Timing Preamplifier, or other preamplifiers utilizing the industry-standard preamplifier power plug.

Electrical and Mechanical

Power Required	The Model 9307 derives its power from a NIM bin/power supply, such as the ORTEC Model 4001A/4002D. Required dc voltages and currents are: +12 V at 35 mA, +6 V at 70 mA, –6 V at 360 mA, and –12 V at 100 mA.
Weight	Net  0.9 kg (2.0 lb).   Shipping  1.8 kg (4.0 lb).
Dimensions	NIM-standard single-width module, 3.43 X 22.13 cm (1.35 X 8.714 in.) front panel per DOE/ER-0457T.