The Extract Of Information In Pile-up Events For Digital Spectrum

In nuclear physics experiments,the energy information of decay product is critical for studying the properties of nuclear structure.So it is an important task to get the energy information of decay product as precise as possible.The nuclear spectroscopy systems play a key role in the detection of the products of nuclear reactions.Because of the fast development of Flash ADC and FPGA,the technology in digital nuclear spectrum measurement systems(DNSMS) has been improved enough and its performance now is comparable with analogues systems.A set of DNSMS should own functions as bellow:1、Transforming waveform into digital signals;2 、 Processing the input digital signals;3 、 Display the results of processing and store the data.The systems for processing input digital signals is the core part of DNSMS.It is its responsibility to exam the height of signals and if the signal matches the condition,it will estimate the baseline of signals 、filtering and shaping 、obtaining the information of height and time of signals、pile up rejection and record all waveform of input signals.It is also the main content in this paper.There is a drawback in DPHA which is used in experiments:It can’t readout the energy of signals when two or more signals arrive in very short time,although it may recognized them.So the function of recording waveform is of great importance:we can process the input signal offline.How to readout the energy in pileup events as precise as possible by adjusting parameters is the major purpose of this paper.In this paper we discussed the relation between the rise time、baseline estimate and height analysis;It has been found the baseline restoration will affect the energy resolution;A new method to evaluate the arrival time of signals has been established.At last,the energy information of pileup events in experimental data is extracted.