A knockout reaction induced by ^6He at 61.2 MeV/u was carried out at the HIRFL-RIBLL ra- dioactive beam line. The α core fragments at forward angles were detected in coincidence with the recoiled protons at large ang...A knockout reaction induced by ^6He at 61.2 MeV/u was carried out at the HIRFL-RIBLL ra- dioactive beam line. The α core fragments at forward angles were detected in coincidence with the recoiled protons at large angles. From this coincident measurement the valence nucleon knockout mechanism and the core knockout mechanism can be separated according to the polar angle correlation between the core fragments and the recoiled protons. It is demonstrated that, when reconstructing the resonant state of a weakly bound nucleus, the contamination resulting from the core knockout mechanism should be eliminated in order to obtain the correct structure information.展开更多
Differential cross sections for the quasi-elastic scattering of^16 C at 47.5 MeV/nucleon from ^12 C target are measured.Coupled-channels calculations are carried out and the optical potential parameters are obtained b...Differential cross sections for the quasi-elastic scattering of^16 C at 47.5 MeV/nucleon from ^12 C target are measured.Coupled-channels calculations are carried out and the optical potential parameters are obtained by fitting the experimental angular distribution.展开更多
The Isochronous Mass Spectrometry is a high accurate mass spectrometer. A secondary electrons time detector has been developed and used for mass measurements. Secondary electrons from a thin carbon foil are accelerate...The Isochronous Mass Spectrometry is a high accurate mass spectrometer. A secondary electrons time detector has been developed and used for mass measurements. Secondary electrons from a thin carbon foil are accelerated by an electric field and deflected 180°by a magnetic field onto a micro-channel plate. The time detector has been tested with alpha particles and a time resolution of 197 ps （FWHM） was obtained in the laboratory. A mass resolution around 8×10^-6 for Am/m was achieved by using this time detector in a pilot mass measurement experiment.展开更多
A pilot experiment of mass measurement was performed at CSRe with the method of isochronous mass spectrometry. The secondary fragments produced via RIBLL2 with the primary beam of 400 MeV/u ^36Ar delivered by CSRm wer...A pilot experiment of mass measurement was performed at CSRe with the method of isochronous mass spectrometry. The secondary fragments produced via RIBLL2 with the primary beam of 400 MeV/u ^36Ar delivered by CSRm were injected into CSRe. The revolution periods of the stored ions,which depend on the mass-to-charge ratios of the stored ions,were measured with a time-of-flight detector system. The results show that the mass resolution around 8×10^-6 for △m/m is achieved.展开更多
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TekVIS...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。展开更多
A prototype of time-of-flight positron emission computed tomography （TOF-PET） has been developed for acquiring the coincident detection of 511 keV γ-rays produced from positron annihilation. It consists of two 80.5...A prototype of time-of-flight positron emission computed tomography （TOF-PET） has been developed for acquiring the coincident detection of 511 keV γ-rays produced from positron annihilation. It consists of two 80.5 minx80.5 mm LYSO scintillator arrays （composed of 35 ×35 pixel finger crystals） with the position sensitive photomultiplier tubes R2487 as the readout. Each array is composed of 2 mm ×2m×15 mm finger crystals and the average pixel pitch is 2.30 mm. The measured results indicate that the TOF information has the potential to significantly enhance the image quality by improving the noise variance in the image recon- struction. The best spatial resolution （FWHM） of the prototype for the pairs of 511 keV T-rays is 1.98 mm and 2.16 mm in the x and y directions, respectively, which are smaller than the average pixel pitch of 2.30 mm.展开更多
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...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.展开更多
基金Supported by National Basic Research Program (973 Program) of China (2007CB815002)National Natural ScienceFoundation of China (11035001,10775003,10827505,J0730316)
文摘A knockout reaction induced by ^6He at 61.2 MeV/u was carried out at the HIRFL-RIBLL ra- dioactive beam line. The α core fragments at forward angles were detected in coincidence with the recoiled protons at large angles. From this coincident measurement the valence nucleon knockout mechanism and the core knockout mechanism can be separated according to the polar angle correlation between the core fragments and the recoiled protons. It is demonstrated that, when reconstructing the resonant state of a weakly bound nucleus, the contamination resulting from the core knockout mechanism should be eliminated in order to obtain the correct structure information.
基金Supported by the National Basic Research Program of China under Grant No 2007CB815002, the National Natural Science Foundation of China under Grant Nos 10405002, 10775003 and 10720003, the Found for Fostering Talents of Basic Science （NFFTBS） （J073316）.
文摘Differential cross sections for the quasi-elastic scattering of^16 C at 47.5 MeV/nucleon from ^12 C target are measured.Coupled-channels calculations are carried out and the optical potential parameters are obtained by fitting the experimental angular distribution.
基金Supported by National Natural Science Foundation of China (10635080, 10221003)State Key Development Program of BasicsResearch of China (2007CB815000)Knowledge Innovation Project of Chinese Academy of Sciences (CXTD-J2005-1, KJCX2-SWN18)
文摘The Isochronous Mass Spectrometry is a high accurate mass spectrometer. A secondary electrons time detector has been developed and used for mass measurements. Secondary electrons from a thin carbon foil are accelerated by an electric field and deflected 180°by a magnetic field onto a micro-channel plate. The time detector has been tested with alpha particles and a time resolution of 197 ps （FWHM） was obtained in the laboratory. A mass resolution around 8×10^-6 for Am/m was achieved by using this time detector in a pilot mass measurement experiment.
基金Supported by National Natural Science Foundation of China (10635080, 10221003)State Key Development Program of Basics Research of China (2007CB815000)Knowledge Innovation Project of Chinese Academy of Sciences (CXTD-J2005-1, KJCX2-SW- N18)
文摘A pilot experiment of mass measurement was performed at CSRe with the method of isochronous mass spectrometry. The secondary fragments produced via RIBLL2 with the primary beam of 400 MeV/u ^36Ar delivered by CSRm were injected into CSRe. The revolution periods of the stored ions,which depend on the mass-to-charge ratios of the stored ions,were measured with a time-of-flight detector system. The results show that the mass resolution around 8×10^-6 for △m/m is achieved.
文摘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。
基金Supported by National Natural Science Foundation of China (10305015,10475098)West Light Foundation of Chinese Academy of Sciences(0801010XBB)Major Foundation Program of Chinese Academy of Sciences(O701050YZD)
文摘A prototype of time-of-flight positron emission computed tomography （TOF-PET） has been developed for acquiring the coincident detection of 511 keV γ-rays produced from positron annihilation. It consists of two 80.5 minx80.5 mm LYSO scintillator arrays （composed of 35 ×35 pixel finger crystals） with the position sensitive photomultiplier tubes R2487 as the readout. Each array is composed of 2 mm ×2m×15 mm finger crystals and the average pixel pitch is 2.30 mm. The measured results indicate that the TOF information has the potential to significantly enhance the image quality by improving the noise variance in the image recon- struction. The best spatial resolution （FWHM） of the prototype for the pairs of 511 keV T-rays is 1.98 mm and 2.16 mm in the x and y directions, respectively, which are smaller than the average pixel pitch of 2.30 mm.
基金Supported by National Natural Science Foundation of China(10925526,11079044)
文摘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.
