Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
Abstract： A fully digital beam position monitoring system (DBPM) has been designed for SSRF (Shanghai Synchrotron Radiation Facility). As analog-to-digital converter (ADC) is a crucial part in the DBPM system, the sampling methods should be studied to achieve optimum performance. Different sampling modes were used and compared through tests. Long term variation among four sampling channels, which would introduce errors in beam position measurement, is studied, too. An interleaved distribution scheme was designed to address this issue. To evaluate the sampling methods, in-beam tests were conducted in SSRF. Test results indicate that with proper sampling methods, a turn-by-turn (TBT) position resolution better than 1 μm is achieved, and the slow-acquisition (SA) position resolution is improved from 4.28 μm to 0.17 μm.
Subjects: Nuclear Science and Technology >> Nuclear Materials and Techniques submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
Abstract： It was learned that 99 % degradation rate of carbamazepine (CBZ) (75 mg L-1) in solutions was got under 10 kGy by EB (electron beam) irradiation while 15.74% and 96.02% CBZ (2 mg L-1) degradation rate was got by UV and UV/H2O2 process in 180 min. EB-radiolysis was thought to be an efficient and energy-saving method to decompose CBZ in comparison of energy consumption between EB irradiation and UV/H2O2. Alkali metal cations which existed in surface water have little inhibition on the degradation of CBZ under EB and UV/H2O2 process. The anions usually existed in surface water had little suppression on EB-radiolysis of CBZ, while have an inhibition on UV-photodegradation of CBZ. Fe3+ promoted the degradation under EB irradiation and UV (ultraviolet) irradiation because of being the OH. promoter. In addition, Fe2+ hugely enhanced the degradation of CBZ under UV irradiation. On the basis of the intermediates’ appearance during the radiolysis, the main degradation pathway for the mineralization of CBZ was proposed under EB irradiation. It came to a conclusion that EB-radiolysis was an efficient and energy-saving method to completely mineralize CBZ.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
Abstract： High precision time measurement is required in the readout of the neutron wall and TOF walls in the external target experiment of the Cooling Storage Ring (CSR) project in the Heavy Ion Research Facility in Lanzhou (HIRFL). Considering the time walk correction, both time and charge are measured in the readout electronics. In this 16-channel measurement module, time and charge information are digitized by TDCs at the same time based on the Time-Over-Threshold (TOT) method; meanwhile, by employing high-density ASIC chips, the electronics complexity is effectively reduced. Test results indicate that this module achieves a time resolution better than 25 ps and a charge resolution better than 5% over the input amplitude range from 50 mV to 3 V.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
Abstract： This article presents a prototype of beam position and phase measurement (BPPM) electronics designed for the LINAC in China Accelerator Driven Sub-critical system (ADS). The signals received from the Beam Position Monitor (BPM) detectors are narrow pulses with a repetition frequency of 162.5 MHz and a dynamic range more than 40 dB. Based on the high-speed high-resolution Analog-to-Digital conversion technique, the input RF signals are directly converted to In-phase and Quadrature-phase (IQ) streams through under-sampling, which simplifies both the analog and digital processing circuits. All signal processing is integrated in one single FPGA, in which real-time beam position, phase and current can be obtained. A series of simulations and tests have been conducted to evaluate the performance. Initial test results indicate that this prototype achieves a phase resolution better than 0.1 degree and a position resolution better than 20 μm over a 40 dB dynamic range with the bandwidth of 780 kHz, which is well beyond the application requirements.
Subjects: Nuclear Science and Technology >> Nuclear Detection Technology and Nuclear Electronics submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
Abstract： In this paper, a high precision vernier delay line (VDL) TDC (Time-to-Digital Convertor) in an actel flash-based Field-Programmable-Gate-Arrays A3PE1500 is implemented, achieving a resolution of 16.4-ps root mean square value or 42-ps averaged bin size. The TDC has a dead time of about 200 ns while the dynamic range is 655.36 μs. The double delay lines method is employed to cut the dead time in half to improve its performance. As the bin size of the TDC is dependent on temperature, a compensation algorithm is adopted as temperature drift correction, and the TDC shows satisfying performance in a temperature range from –5°C to +55°C.
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