A fast, programmable, stand-alone pulse generator emulating spectroscopy nuclear events

The design of a fast, programmable, stand-alone pulse generator emulating spectroscopy nuclear events is described. The generator is one unit in a system aiming to test the validity of the simulation and theoretical work relating to the shaping, acquisition, and processing of spectroscopy signals in different experimental situations arising from different technical and scientific fields. The generator output, which also includes piled-up shapes, can be used in many different ways. For example, it can be used: (1) as an input to a charge sensitive preamplifier and shaping amplifier system; (2) as an input to a module for real-time digital shaping of spectroscopy pulses; and (3) it can generate a digital sequence emulating a digitally sampled analog pulse. The signals that it can emulate include those from simple charge sensitive preamplifiers, from more refined analog shapers, and the signals generated directly from scintillation detectors. The main element of the generator is the Analog Devices 21060, a fast and flexible digital signal processor (DSP). This paper considers various generator configurations arising from the need to reach a compromise among generator speed, shape resolution, and memory requirements. It is possible to program both the emulated average counting rate and the time interval between two consecutive samples (tns) using a predetermined pulse shape. The minimum tns value is equal to 10 ns in parallel configurations.