Development of a 2D digital Coincidence Doppler Broadening Spectrometer

Abstract

A: A 2D digital spectrometer for coincidence measurement of Doppler broadening of positron annihilation radiation is developed and tested. The spectrometer is based on a 14-bit waveform digitizer which gives the possibility of fast and direct sampling of the preamplifier signals of the HPGe detectors and preserves the information required by the physics of Doppler broadening spectroscopy. Some features of the digital spectrometer are compared with its analog counterpart. Superior energy resolution, better peak symmetry, effective elimination of ballistic deficit and better stabilization of peak position are the advantages of the digital spectrometer. The performance of the digital spectrometer to support the CDBS experiment is tested by investigation on the electronic structure of some elements at 1 st series of transition metals. The results show that the spectrometer is sensitive enough to distinguish the electronic structure of 3d metals differing a little in their valance band configuration.

Development of a 2D digital proton–proton scattering technique for hydrogen depth profiling

“…The digital pulse processing (DPP) firmware can replace all the nuclear electronics (such as an amplifier, sum, gate, and coincidence modules) used for the analog spectrometer. The details related to the setting of the digitizer and how to make coincidences by its software have been provided in our previous paper 16 . To obtain maximum counting efficiency, the coincidence time window should be adjusted carefully.…”

“…The details related to the setting of the digitizer and how to make coincidences by its software have been provided in our previous paper. 16 To obtain maximum counting efficiency, the coincidence time window should be adjusted carefully.…”

Digital signal processing for neutron-gamma discrimination using a liquid scintillator detector

“…As shown in figure 1, in the designed configuration, all the analog nuclear electronics are omitted, and all the functionalities are performed inside the Field Programmable Gate Array (FPGA) without any use of external cables and delay lines. The advantages and limitations of digital signal processing for nuclear spectroscopy have been described in our previous paper [20]. The digitizer samples directly from the anode signal of the detector and implements a dual gate Charge to Digital Converter (QDC), discriminator, and gate generator.…”

A fully digital coincidence Doppler broadening spectrometer based on FPGA

“…CDB spectrometer, whose analog circuits dominate signal processing, suffers from complicated set up processes, limited freedom of parameter configuration, and vulnerability to environment fluctuation as the analog setup needs a collection of standard Nuclear Instrument Modules (NIMs), including amplifier, multichannel analyzer, timing single channel analyzer, fast coincidence, etc. Digital circuits featuring high stability, flexibility, and improved performance have been adopted to build a nuclear spectrometer [10][11][12][13][14][15]. In refs.…”

“…In refs. [12][13][14][15], the digital CDB spectrometer is implemented based on a digitizer whose performance is tested. The results show that the digital CDB spectrometer has better performance in several aspects, including better energy resolution, more effective elimination of the ballistic deficit, etc.…”