Real time digital pulse processing applied to heavy ion irradiation

Abstract- Three algorithms for real-time digital pulse processing of fast detector signals (1-100µs) are described and implemented through Field Programmable Gate Arrays (FPGAs). The signal from a PIN diode used as ion detector is amplified and digitized with a fast flash ADC at a rate of 10 MHz/s. Whenever a preset threshold is exceeded, an event is detected. The pulse maximum is determined using one of the three methods, characterized by decreasing response times and increasing the result confidence degree: (1) searching for the maximum, (2) integrating the signal and (3) looking for the derivative sign. The system is applied to fabricate polymer films with a preset number of ion hits at preset distances. The technique can be generalized to real-time processing of pulsed signals from arbitrary sensors and transducers. I