A resonant Schottky pickup with high sensitivity, built by GSI, will be used for nuclear mass and lifetime measurement at CSRe. The basic concepts of Schottky noise signals, a brief introduction of the geometry of the detector, the transient response of the detector, and MAFIA simulated and perturbation measured results of characteristics are presented in this paper. The resonant frequency of the pickup is about 243 MHz and can be slightly changed at a range of 3 MHz. The unloaded quality factor is about 1072 and the shunt impedance is 76 kΩ. The measured results of the characteristics are in agreement with the MAFIA simulations.
We study the response function of the neutron wall for 300 MeV neutrons with GEANT4 simulations. The methods to find the correct neutron incident position and time are discussed, and the neutron emission angle and energy are reconstructed and compared with the simulation.
The luminosity for a WASA-at-COSY experiment involving the pd reaction at 2.14 GeV proton- beam energy is determined by the forward pd elastic scattering, which yields an average beam-on-target value of [5.2±0.3（stat）±0.3（syst）] × 10^30 s^-1 cm^-2. In addition, the forward pd elastic-scattering angular distribution is obtained with four-momentum transfer squared -t between 0.16 （GeV/c）2 and 0.78 （GeV/c）2 at this beam energy, which is compared with other experimental data and the pd double scattering model.
等时性模式奇异核的质量测量(Isochronous Mass Measurement)是兰州重离子冷却储存环(HIRFL-CSR)上的物理研究项目之一。离子在CSRe中回旋时,每次穿过飞行时间探测器产生的信号经放大后由数字示波器DPO 71254采集。基于LabView和TekVISA的获取程序被开发出来用于自动存储示波器采集的数据、显示时域波形及在线分析得到离子飞行时间的频谱。主要介绍了CSRe上等时性模式奇异核质量测量的方法、数据获取系统及测量结果。
A microscopic cluster model with a fully correlated Gaussian basis is developed. In the model, the stochastic variational method is used in order to calculate the ground-energy and the mean-square radius conveniently. Based on this model, the ground-energy level and radius of the neutron halo nucleus, ^6He, are calculated as a α＋n＋n three-cluster model. The results are in good agreement with the experimental data.
LPT （Lanzhou Penning Trap） is an ion-trap facility in Lanzhou, China. As ions can be cooled to an extremely small phase space and can be stored for a very long time, ion traps are a perfect instrument for high precision mass measurements. A system with specialized electronics for LPT is under construction now. This system could be used for voltage and timing control to make ions moving in a special mode, and the data acquisition and analysis online/offline could be achieved in the mean time. The requirements of control system, the distribution of hardware, the overview of software, and the latest progress of LPTCtrlSys （Lanzhou Penning Trap Control System） are presented.
A high detection efficiency calorimeter which is used to detect γ-rays with energies from 1 MeV up to 10 MeV as well as light charged particles has been proposed. Design of the geometry, results of the crystal tests and Monte Carlo simulations are presented in this paper. The simulation results confirm that the calorimeter can obtain high detection efficiency and good energy resolution with the current designed geometry. And the calorimeter is competent for the future External Target Facility （ETF） experiments.
The model of three-body Borromean halo nuclei breakup was described by using standard phase space distributions and the Monte Carlo simulation method was established to resolve the detection problem of two neutrons produced from breakup reaction on the neutron wall detector. For 6He case, overall resolution ~rEk for the Oaussiaal part of the detector response and the detection efficiency including solid angle acceptance with regard to the excitation energy Ek are obtained by the simulation of two neutrons from 6He breakup into the neutron wall. The effects of the algorithm on the angular and energy correlations of the fragments are briefly discussed.
