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UPGRADE OF IBA CYCLONE® 3 CYCLOTRON
No full textSome specific applications of 15O2 need a stand alone
production machine to avoid disrupting the hospital main
PET cyclotron. Due to recent renewal in interest, IBA has
decided to improve the design of its Cyclone® 3 which
accelerates D+ ions to energy of more than 3 MeV and
which was originally developed for this purpose.
The main improvement relates to the magnetic structure.
In the existing design the vertical focusing is obtained by
four straight pole-sectors that are mounted on the circular
base of the pole. In the new design these are replaced by
three spiralled pole sectors. This modification changes the
rotational symmetry from four to three and improves the
vertical focusing properties of the machine. Also the main
coil and the return yoke were slightly modified. This
allowed increasing the extraction energy by about 10 %
from 3.3 MeV to 3.6 MeV.
This new design will improve the transmission in the
cyclotron and will result in an extraction efficiency of more
than 80% using an electrostatic deflector. For the prototype
the goal is to obtain an extracted current of 50 μA. This
value should rise to 70 μA for subsequent machines,
representing a doubling of the existing performance.
In the paper, results of magnetic field optimization and
extraction calculations are presented.IMP;Chinese Academy of Science
CONSISTENCY IN MEASUREMENT OF BEAM PHASE AND INTENSITY USING LOCK-IN AMPLIFIER AND OSCILLOSCOPE SYSTEMS
No full textThe phase probes (PPs) are installed in all cyclotrons and
beam transport lines of RIBF, and the beam-bunch signals
that are detected nondestructively by these PPs are used for
tuning of isochronism of cyclotrons and for monitoring the
beam phase and beam intensity. We mainly use a newly developed
system that incorporates a lock-in amplifier (LIA)
for those tuning and monitoring; however, a conventional
measurement method using an oscilloscope (OSC) system
is also used. In this study, we investigated the consistency
in the measurements carried out using LIA and OSC systems
by FFT analyzing the observed data. Additionally, we
investigated the measurement accuracy of LIA and OSCIMP;Chinese Academy of Science
COMMISSIONING OF THE JYFL MCC30/15 CYCLOTRON
No full textThe new MCC30/15 cyclotron from NIIEFA, St.
Petersburg, Russia, arrived at Jyväskylä on 10th of August,
2009, as a partial compensation of the Former Soviet
Union debt to Finland. The cyclotron required an
extension for the old experimental hall. The building of
the extension started in late August, 2008, and it was
scheduled to be ready by Midsummer, 2009. Both the
cyclotron and the building projects took a little more time
than planned. However, the delay of both projects was
less than two months, and so the building was ready to
host the cyclotron by the beginning of August, 2009.
The installation of the cyclotron was done by the
manufacturer’s (NIIEFA) specialists. Before the end of
November 2009 the maximum extracted proton intensity
(in pulses) was 200 μA, twice the guaranteed value, and
62 μA for deuterons, which is also more than guaranteed
(50 μA). The final acceptance protocol was signed on 30th
of April, 2010.IMP;Chinese Academy of Science
抑制survivin表达增强人肝癌HepG2细胞对高线性能量转移射线的辐射敏感性；Inhibiting Survivin Expression Increases The Radiosensitivity of Human Hepatoma HepG2 Cells to High-LET Radiation
No full text探讨了肿瘤细胞中survivin的表达对高线性能量转移(LET)射线辐射敏感性的影响.根据Gen Bank提供的survivin序列,合成特异性survivin-siRNA寡核苷酸,转染人肝癌HepG2细胞,抑制survivin的表达.发现siRNA转染后诱导了HepG2细胞G2/M期阻滞,增加了自发性和辐射诱导的细胞凋亡.在高线性能量转移(LET)碳离子辐照后,siRNA转染细胞的克隆存活率明显下降.这些结果表明survivin表达是HepG2细胞产生对高LET射线辐射抗性的关键因素
一维位置灵敏法拉第筒的数据获取系统
No full text简要介绍兰州重离子加速器国家实验室320 kV高压ECR实验平台原子分子物理终端上使用的一维位置灵敏法拉第筒的数据获取系统。该系统硬件由64通道电流/电压转换放大器和PCI-6224数据采集卡构成,并通过编写LabVIEW程序,实现数据的准确、同步、实时与高速采集。经验证,该获取系统简单易用,可靠性高,完全符合设计要求
生物还原药物AQ4N在肿瘤治疗增敏中的研究进展
No full text目的观察尼美舒利(nimesulide)对人乳腺癌细胞MCF-7辐射敏感性的影响,并探讨其可能机制。方法实验分为对照组、加药组、单纯照射组(radiation treatment,RT)及加药照射组,用噻唑蓝(MTT)法检测尼美舒利对MCF-7细胞生长抑制率的影响,并选择用药后72h测得的IC20-IC30(抑制浓度,inhibiting concentration,IC)对应的药物浓度作为辐射增敏工作浓度;克隆形成实验检测尼美舒利对MCF-7的放射增敏作用;通过流式细胞仪检测细胞周期分布的变化。Western印迹法检测与凋亡相关蛋白Bcl-2和Bax的表达水平;并用单细胞凝胶电泳技术检测DNA的损伤及修复。结果尼美舒利对MCF-7细胞的生长抑制作用呈时间依赖性和剂量依赖性,但对周期分布无明显变化。尼美舒利加药照射组与单纯照射组比较,克隆存活曲线的肩区变窄,bcl-2表达下调,但对Bax表达没有明显影响。尼美舒利本身不明显增加MCF-7的DNA损伤,但可明显延缓放射引起的SSB的修复。结论提示尼美舒利对人乳腺癌MCF-7细胞株具有辐射增敏作用,其放射增敏机制可能通过抑制DNA损伤修复并下调bcl-2来得以实现
基于FPGA的CSR高频控制系统相位求解模块设计
No full textCSR高频控制系统需要对高频正弦波激励信号的幅度、相位、频率进行稳定控制。相位arctan(Q/I)求解是必不可少的模块。论述了一种新的基于FPGA平台和对称查找表法(SBTM)的求解相位arctan(Q/I)的方法,做了详细的理论分析,给出了具体实现的代码和结果。该模块精度高,消耗资源少,可直接应用于CSR高频控制系统
X射线辐照后人肝细胞、肝癌细胞存活与端粒酶活性关系的研究
No full text利用X射线对体外培养的人肝癌细胞SMMC-7721和正常人肝细胞HL-7702进行辐照,以细胞克隆形成法测定细胞存活率,多聚酶链式反应银染端粒重复序列扩增法(Telomeric repeat amplification protocol,TRAP-PCR)检测细胞中端粒酶活性变化,探讨辐照后细胞存活与细胞中端粒酶活性变化的关系。结果表明,SMMC-7721和HL-7702细胞的存活率都随辐照剂量的增加而相应降低。在1-4Gy剂量范围内,两种细胞的端粒酶活性变化均呈剂量依赖性增强。但在1Gy、2Gy、3Gy剂量下,SMMC-7721其端粒酶活性较对照(0Gy)细胞低;当辐照剂量达4Gy时,端粒酶活性略高于对照细胞。在1-4Gy剂量范围内,HL-7702和SMMC-7721的细胞存活与端粒酶活性在变化趋势上呈负的关系
Discovery of Highly Excited Long-Lived Isomers in Neutron-Rich Hafnium and Tantalum Isotopes through Direct Mass Measurements
No full textA study of cooled Au-197 projectile-fragmentation products has been performed with a storage ring. This has enabled metastable nuclear excitations with energies up to 3 MeV, and half-lives extending to minutes or longer, to be identified in the neutron-rich nuclides Hf-183,Hf-184,Hf-186 and Ta-186,Ta-187. The results support the prediction of a strongly favored isomer region near neutron number 116
Higher Moments of Net Proton Multiplicity Distributions at RHIC
No full text200 GeV corresponding to baryon chemical potentials (mu(B)) between 200 and 20 MeV. Our measurements of the products kappa sigma(2) and S sigma, which can be related to theoretical calculations sensitive to baryon number susceptibilities and long-range correlations, are constant as functions of collision centrality. We compare these products with results from lattice QCD and various models without a critical point and study the root s(NN) dependence of kappa sigma(2). From the measurements at the three beam energies, we find no evidence for a critical point in the QCD phase diagram for mu(B) below 200 MeV