Development of the new spectrometric channel for the SND electromagnetic calorimeter
The Spherical Neutral Detector (SND) is one of the two detectors operating at VEPP-2000 e+e- collider, which is located at Novosibirsk, Russia. The main part of the SND is a three-layer electromagnetic calorimeter (EMC), which consists of 1640 NaI(Tl) counters. Each counter includes NaI(Tl) crystal, vacuum phototriode, and charge-sensitive preamplifier.
It is planned to improve the EMC spectrometric channel. There are two goals. The first one is to provide each channel with 1 ns or better time resolution measurement (now 5 ns) while preserving current amplitude resolution. It's useful for reliable detection of low-speed anti-neutrons, producing in e+e-->n anti-n reaction near threshold. This new channel is also needed for increasing the operation rate of the EMC electronics. Higher operation rate is important due to increase of the VEPP-2000 luminosity by about 5 times after its recommissioning. To achieve that, new modules for shaping and digitizing signal were designed, manufactured and tested.
The new shaping module F12M is developed to achieve optimal signal shape for best time and amplitude resolution.
The new Z24 module based on the Xilinx SoC Zynq digitizes and processes the signal waveforms oscillogram for calculation its time and amplitude with the specially developed algorithm.
Detailed overview of the F12M and Z24 electronic designs, special algorithm for signal processing and current measurement results are presented in the report.