Test system of the front-end readout for an application-specific integrated circuit for the water Cherenkov detector array at the large high-altitude air shower observatory

The water Cherenkov detector array (WCDA) is an important part of the large high-altitude air shower observatory (LHAASO),which is in a research and development phase.The central scientific goal of LHAASO is to explore the origin of high-energy cosmic rays of the universe and to push forward the frontier of new physics.To simplify the WCDA's readout electronics,a prototype of a front-end readout for an application-specific integrated circuit (ASIC) is designed based on the timeover-threshold method to achieve charge-to-time conversion.High-precision time measurement and charge measurement are necessary over a full dynamic range [1-4000 photoelectrons (P.E.)].To evaluate the performance of this ASIC,a test system is designed that includes the front-end ASIC test module,digitization module,and test software.The first module needs to be customized for different ASIC versions,whereas the digitization module and test software are tested for general-purpose use.In the digitization module,a field programmable gate array-based time-todigital converter is designed with a bin size of 333 ps,which also integrates an inter-integrated circuit to configure the ASIC test module,and a universal serial bus interface is designed to transfer data to the remote computer.Test results indicate that the time resolution is better than 0.5 ns,and the charge resolution is better than 30％root mean square (RMS) at 1 P.E.and 3％ RMS at 4000 P.E.,which are beyond the application requirements.     

Clock distribution and local oscillator of a digital low-level radio-frequency board for SSRF

In the storage ring RF system of Shanghai Synchrotron Radiation Facility, the clock distribution and the local oscillator are two parts of the digital low level radio frequency hardware board. In this paper, we designed and produced the clock distribution and the local oscillator board using the AD9858 and AD9510 chips. The results show that the phase noise of the local oscillator signal is lower than 100dBc/Hz with 50 kHz offset.     

基于VEE软件的加速管场分布测量系统的研制

针对加速管调谐中的一个重要参数场分布的测量,开发了两套基于不同网络分析仪的加速管纵向场分布测量虚拟仪器系统.该系统的开发采用了可视化工程设计环境(Visual engineering environment,VEE),引入了虚拟仪器技术.采用VEE的Direct I/O控件读写仪器,避免了做底层协议方面的工作,减少了开发人员的工作量.该系统同时能为用户提供友善的界面,降低操作要求,提高了测量工作的效率和稳定性.     

The study of aeroball system for measuring 3D neutron flux distribution in reactor core

Aeroball system is attractive in several aspects because it can easily transport the map of neutron flux distribution to be measured from incore to outside of a reactor vessel.However,before the aeroball system is put to practical use in the heating reactor.there are four topics that have to be further studied.They are the stability of the activated positions,enhancement of signal/noise(S/N)ratio,distributed control and data-acquisition system and on-lin nbeutron flux distribution reconstruction.Besides describing the rasons for them,this paper gives out the theory,concept and solution about the first two topics and it is helptul to give the possibility to enhance the reactor-power.