Institutional Repository of Institute of Modern Physics, CAS
Not a member yet
5769 research outputs found
Sort by
Precision isochronous mass measurements at the storage ring CSRe in Lanzhou
No full textDirect mass measurements of (78)Kr projectile fragments have been performed in the recently commissioned storage ring CSRe employing the isochronous mass spectrometry method. A new data-analysis technique has been developed to correct the drifts in the revolution frequencies caused by instabilities of the magnetic fields in the CSRe. thus yielding a mass resolving power of R = m/Delta m approximate to 1.7 x 10(5) (sigma). Masses for (45)V, (47)Cr, (49)Mn and (51)Fe nuclei are determined with a relative mass precision of delta m/m approximate to 2 x 10(-7) (sigma) which is an improvement by a factor of similar to 2 compared to the literature values. (C) 2011 Elsevier B.V. All rights reserved
A self-circulation helium liquefaction system with five 4 K G-M cryocoolers
No full textA self-circulation helium liquefaction system (SCHLS) with five 4 K G-M cryocoolers is developed to supply liquid helium (LHe) for SECRAL (a superconducting ECR ion source used in Lanzhou city, China). LHe is vaporized in SECRAL and warmed up to room temperature. SCHLS will re-liquefy the helium gas at a rate of 83.2 L/day under normal atmosphere pressure. With SCHLS, SECRAL system can run online without any interruption of refilling LHe. (C) 2010 Elsevier Ltd. All rights reserved
马鞍型铜导线线圈的绕线装置
No full text<p><font face="宋体" size="3">实用新型涉及科研及工业用的电磁铁线圈制造技术领域，尤其是涉及一种马鞍型铜导线线圈的绕线装置。包括底座，线圈模型构件和蜗轮蜗杆传动系统，底座上设有支架，轴承座安装在支架上，蜗轮蜗杆传动系统的蜗杆通过轴承安装在轴承座上，支架左右两端固定有绕线机旋转用的旋转轴座，传动轴通过轴套安装在轴座上；其采用线圈模型构件和蜗轮蜗杆传动系统等合理实际的工艺方法和机械结构，实现了马鞍形线圈的绕制功能，最大程度的降低制造成本，提高生产效率，同时也保障了线圈的形状及质量。</font></p
重离子治癌同步加速器中射频激励引出方法及其装置
No full text<p><font face="宋体" size="3">发明主要涉及一种将重离子治癌同步加速器中的重离子束在一定时间内(通常是秒量级)均匀引出到治癌终端的方法及其装置。一种重离子治癌同步加速器中射频激励引出方法，包括有如下步骤：1.采用四极磁铁调整储存束流的水平包络振荡波数Q接近同步加速器三分之一共振线；2.在引出开始阶段，改变六极磁铁强度，使束流动力学孔径缩小，最终同步加速器相空间稳定区域刚好大于储存束流的发射度；3.在引出过程中，在储存环激励处施加射频电场，并保证在相空间中，同一个离子被射频电场作用的位置相同；离子在射频电场的作用下，发射度逐渐增大，最终逃逸出相空间稳定区域，进入静电偏转板被引出。</font></p
FPGA-based Quench Detection System for Super-FRS Super-ferric Dipole Prototype
No full text介绍了FAIR项目Super-FRS超导二极磁铁样机的基于FPGA的失超探测系统.该失超探测系统采用平衡桥路法,并通过两组独立桥路以消除失超探测死区.通过NI PXI-7830R FPGA模块实现平滑滤波和失超判断算法,并给出失超触发信号.失超数据采集模块采用预采样技术,将失超前后一段时间内的数据采集下来,以便进行后续分析.通过测试,失超探测模块准确检测到了失超的发生,并触发失超保护电路和失超数据采集模块工作,有效地保护了超导二极磁铁The quench detection system for Super-FRS super-ferric dipole prototype magnet of FAIR has been designed and built. The balance bridge was used to detect quench signal. In order to avoid blind zone of quench detection, two independent bridges were used. NI PXI-7830R FPGA was used to implement filter to quench signal and algorithm of quench decision and to produce quench trigger signal. Pre-sample technique was used in quench data acquisition. The data before and after quench could be recorded for analysis later. The test result indicated that the quench of the dipole's superconducting coil could be reliably detected by the quench detection 
重离子及质子治疗中Bragg峰展宽的计算方法及其旋转降能装置
No full text本发明主要涉及重离子及质子治疗中布拉格峰(Bragg峰)展宽的模型建立及参数计算的方法。一种重离子及质子治疗中Bragg峰展宽的计算方法，其主要特点包括有如下步骤：A.建立数学模型：∫#-+[T]0RBE(LET(x+∫#-+[T]0ν(t)dt])·D(t)·LET[x+∫#-+[T]0ν(t)dt]dt=θ(x)； B.用蒙特卡罗法求解模型；C.将上述计算结果A*＝(a1*，a2*，a3*，…，an*)作为设计重离子及质子治疗中Bragg峰展宽降能装置的参数。本发明的优点是，这一模型的建立可以实现Bragg峰的连续移动，使Bragg峰展宽区水平平滑，实现在治癌过程中肿瘤区接收的能量达到完全均匀分
离子加速器高精度脉冲/直流数字电源
No full text本发明涉及一种离子加速器高精度脉冲/直流斩波数字电源。它包括：离子加速器高精度通用数字电源调节器，离子加速器通用数字电源控制器，低压变压器，三相二极管整流与滤波电路，H桥双向斩波电路，高精度电流反馈电路以及负载电路。通过使用离子加速器高精度通用数字电源调节器对斩波式非隔离开关电路的进行控制和调节，实现了一种能脉冲和直流两种运行方式工作的离子加速器高精度数字电源，满足离子加速器数字电源高精度数据采集、高速高精度数字调节、高精度PWM输出等要求；本发明工作方式简单可靠，可以通过本地人机界面对数字电源通讯和操作也可利用CAN总线组网方式对单台或多台数字电源采用远程网络控制；可应用于普通离子加速器和专用离子治癌加速器，或其它类似用途
A TOF-PET prototype with position sensitive PMT readout
No full textA prototype of time-of-flight positron emission computed tomography (TOF-PET) has been developed for acquiring the coincident detection of 511 keV gamma-rays produced from positron annihilation. It consists of two 80.5 mmx80.5 mm LYSO scintillator arrays (composed of 35 x35 pixel finger crystals) with the position sensitive photomultiplier tubes R2487 as the readout. Each array is composed of 2 mm x2 mm x 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 reconstruction. The best spatial resolution (FWHM) of the prototype for the pairs of 511 keV gamma-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