狭长闪烁体光传输的研究

研究了光在狭长闪烁体内的传输问题，推导出了特定情况下的最佳传输条件。对于狭长的高折射率闪烁体，侧面抛光、充分利用全反射。同时将与探测面相对的端面做漫反射处理，可以获得较高的光收集效率。     

基于ENDF/B-VII的部分核素ACE格式光核截面的制作与检验

MCNP5程序可以用于电子加速器驱动次临界系统的建模运算,其调用的截面数据库缺乏部分核素的光核数据。利用NJOY程序将ENDF/B-VII中的7种核素原始光核数据制作成MCNP5可利用的ACE格式的光核数据,并用MCNP5建立模型计算出所加工核素的光中子反应微观截面,得到光中子反应微观截面随光子能量变化曲线,并与IAEA编写的技术文档中各核数据中心的截面曲线进行对比。结果表明,所有核素光核反应数据制作过程正确,但52Cr、58Ni和91Zr的光中子反应微观截面在不同数据库中有一定的差别。      

基于ENDF/B-Ⅶ的部分核素ACE格式光核截面的制作与检验

MCNP5程序可以用于电子加速器驱动次临界系统的建模运算,其调用的截面数据库缺乏部分核素的光核数据。利用NJOY程序将ENDF/B-Ⅶ中的7种核素原始光核数据制作成MCNP5可利用的ACE格式的光核数据,并用MCNP5建立模型计算出所加工核素的光中子反应微观截面,得到光中子反应微观截面随光子能量变化曲线,并与IAEA编写的技术文档中各核数据中心的截面曲线进行对比。结果表明,所有核素光核反应数据制作过程正确,但52Cr、58Ni和91Zr的光中子反应微观截面在不同数据库中有一定的差别。     

切伦科夫光:纳米核药物诊断治疗一体化的新光源

切伦科夫光是放射性核素衰变过程中的发光现象，在生物医学领域受到越来越多的关注。切伦科夫光的可见光波段可以直接被相机捕获实现切伦科夫成像，有望运用于术中导航。同时，切伦科夫光在此过程中作为体内光源的性质也受到关注，将核素作为体内光源结合纳米颗粒进行光动力治疗可以取得较好的肿瘤抑制性。但是由于切伦科夫光的发光效率极低，相关研究仍存在争议，其可能并不是仅有切伦科夫光起作用的结果。虽然切伦科夫光在生物医学领域具有独特运用，但其较低的发光效率是限制其发展的关键因素。基于纳米颗粒-核素相互作用的体系则可解决这一问题，为进一步拓展切伦科夫光在生物医学研究中的应用奠定基础。     

乙腈体系中2′—萘乙酮激发三重态性质的激光光解研究

利用纳秒级激光光解瞬态光谱装置,以355nm激光为激光光源,二苯甲酮、周萘酮为光敏化剂和参比物,研究了2′－萘乙酯激发三重态在乙腈体系下激发三重态量子产额、单线态氧量子产额、激发态衰变反应动力学参数、氧淬灭反应速率常数、三重态摩尔光系数及二苯甲酮激发三重态与2′－萘乙酮之间的能量转移反应速率常数,并得到了2′－萘乙酮在乙腈体系中激发三重态瞬态吸收光谱。     

琥珀酸-氨基葡糖-二价铜络合物清除超氧阴离子自由基的研究

在核黄素水溶液反应体系中,以甲硫氨酸和超氧化物歧化酶为竞争清除剂[1-3],测定了琥珀酸-氨基葡糖-二价铜络合物(Amberacid-chitosan-complexwithcopper(II),ACCC)清除超氧阴离子自由基的反应速率常数。使用254、365nm的紫外光和太阳光为光照源,分别测得清除超氧阴离子自由基的反应速率常数为1.26×109、1.11×109、4.98×108mol-1s-1dm3。本研究还表明,琥珀酸-氨基葡糖-二价铜络合物清除超氧阴离子自由基的效率分别达91%,这与超氧化物歧化酶的清除效率(93%)几乎相同,但远高于用琥珀酸清除超氧阴离子自由基的效率(2.6%)或用氨基葡糖清除…     

血卟啉Y-Hpd和Photofrin-Ⅱ对肿瘤细胞光敏损伤的比较:细胞摄取与光敏化作用

本文比较了血卟啉、Y-Hpd及Photofrim-Ⅱ对S 180瘤细胞和HeLa细胞光动力学杀伤作用、并定量测定了细胞及脂质体内卟啉化合物的浓度。结果表明:在体外Y-Hpd对肿瘤细胞的杀伤作用显著高于Photofrin-Ⅱ和Hp,其生物活性顺序是Y-Hpd、photofrin-Ⅱ、Hp。与Hp和Photofrin-Ⅱ相比、Y-Hpd所含组分在细胞及脂质体内的浓度最高。由此可见细胞内卟啉化合物的水平是评价不同的血卟啉衍生物制剂生物活性的重要参数之一。     

可聚合大分子光引发剂的合成及其引发二缩三丙二醇二丙烯酸酯光聚合动力学的研究

以2-羟基-2-甲基-1-苯基丙酮(2-Hydroxy-2-methyl-1-phenyl propan-1-one,HMPP)、甲苯-2,4-二异氰酸酯(Toluene-2,4-diisocyanate,TDI)、一种双酚A环氧丙烯酸酯(6104)为原料,合成了三种可聚合大分子光引发剂1HMPP-TDI-6104,2HMPP-TDI-6104和3HMPP-TDI-6104.用红外光谱监测反应过程,用光差动热分析法(Photo-Differential scanning calorimetry,Photo-DSC)研究了这三种可聚合大分子光引发剂引发二缩三丙二醇二丙烯酸酯(Tripropylene glycol diacrylate,TPGDA)光聚合动力学,比较了它们与小分子光引发剂HMPP的引发效果,考察了引发剂浓度对TPGDA光聚合动力学的影响.结果表明,这三种可聚合大分子光引发剂与HMPP的性能相差不大.最大反应速率对应的转化率、单体最终转化率均随引发剂浓度增大,达最大反应速率所需时间短.     

硝酸介质中亚硝酰钌配合物的光分解反应动力学研究

研究了硝酸介质中亚硝酰钌配合物的光分解反应，测定了亚硝酰钌配合物的紫外吸收光谱。实验结果表明：在低压汞灯２５４ｎｍ的紫外光照射下，硝酸介质中亚硝酰钌配合物的光分解反应属表观准一级反应；在ｃＨＮＯ３＜２ｍｏｌ／Ｌ时，反应速率常数随硝酸浓度的增加而增大，在ｃＨＮＯ３＞２ｍｏｌ／Ｌ时，反应速率常数随硝酸浓度增大而减小。温度在１０—４０℃时，速率常数随着温度的上升而减小。     

放射性核素标记DIPA-HSA的研究

介绍了用DTPA(二乙三胺五醋酸)作为双官能团螯合剂与HSA(人血白蛋白)进行偶联,以提高放射性核素标记的HSA的体内稳定性的方法。合成了DTPA酸酐,并将其以固态形式加入HSA水溶液,再经Sephadex G50凝胶柱纯化,得到DTPA-HSA。用~(114)In~m标记的方法,测定了在不同反应介质中DTPA与HSA偶联反应的偶联率。~(114)In~m由~(113)In堆照生产。在邻苯二甲酸盐(pH5)、磷酸盐、Hepes等几种缓冲体系中制备了DTPA-HSA的~(99)Tc~m标记物。小鼠体内分布实验表明,以邻苯二甲酸盐为缓冲介质制备的~(99)Tc~m标记物体内稳定性最好。当HSA浓度为15mg/ml,DTPA与HSA摩尔比(n_(DTPA)/n_(HSA))大于3,Sn~(21)-DTPA摩尔比小于0.5时,标记比较合适。     

The Electron Trajectory in a Relativistic Femtosecond Laser Pulse

In this report, we start from Lagrange equation and analyze theoretically the electron dynamics in electromagnetic field. By solving the relativistic government equations of electron, the trajectories of an electron in plane laser pulse, focused laser pulse have been given for different initial conditions. The electron trajectory is determined by its initial momentum, the amplitude, spot size and polarization of the laser pulse. The optimum initial momentum of the electron for LSS （laser synchrotron source） is obtained. Linear polarized laser is more advantaged than circular polarized laser for generating harmonic radiation.     

Quantitative analysis of saindha salt using laser induced breakdown spectroscopy and cross-validation with ICP-MS

Saindha salt is considered to be more advantageous than the other edible salts for the patients suffering from diabetes,blood pressure and kidney diseases.To explore the constituent elements of this salt,laser induced breakdown spectroscopy(LIBS) has been exploited for its qualitative and quantitative analysis.The third harmonic(355 nm) of a Q-switched Nd:YAG laser has been used to produce the saindha salt plasma and the time integrated optical emission spectra were registered using a set of six miniature spectrometers covering the spectral range of 230-805 nm.The spectroscopic analysis of the emission spectra predominately revealed numerous neutral or singly ionized emission lines of Ca,Mg,Na,K,Fe,Sr,Si,Li and Al.The laser produced plasma was characterized by calculating the electron temperature from the Boltzmann plots and the electron number density from the Stark broadened line profile as a function of laser irradiance and distance from the target sample.The relative concentration of the constituent elements was extracted by the integrated line intensities of the strongest spectral line of each element using the self-calibration-LIBS(SC-LIBS) and one-line calibration free-LIBS(OLCF-LIBS) methods.For cross-validation,the LIBS results have been compared with that obtained from the inductively coupled plasma-mass spectroscopy(ICP-MS) showing good agreement.     

Effect of Self-focusing of Gaussian Laser Beam on Second Harmonic Generation in Relativistic Plasma

In the present paper, effect of self-focusing of gaussian laser beam on second harmonic generation in relativistic plasma is investigated. An expression for density perturbation associated with plasma wave has been derived, which acts as a source for second harmonic generation. Moment theory approach has been used to set up wave equation for the laser beam. Effect of the intensity of the laser beam and plasma density on the harmonic yield is studied in detail. It is predicted from the analysis that harmonic yield increases due to increase in the plasma density and intensity of the laser beam.     

Single-event effects in resolver-to-digital converters

Single-event effects (SEEs) in two resolver-to-digital converters (RDCs) have been studied using heavy ions and pulsed laser light. The important role of the pulsed laser in establishing single-event upset (SEU) and single-event latchup (SEL) levels prior to accelerator testing is described, as is its role in evaluating the test software and hardware and in gaining a better understanding of the origins of the SEEs. Results from pulsed-laser testing are in quantitative agreement with those from heavy-ion testing: the RDC-19220 is sensitive to both SEUs and SELs whereas the AD2S80 is less sensitive to SEUs and immune to SEL     

用激光束测试和标定气体径迹探测器

近年来利用激光束产生的电离径迹对径迹探测器进行测试、标定和监测已成为一种强有力的通用方法。本文介绍这种方法的基本原理、实验装置以及它的若干应用。     

A Fast Pulsed Electron Gun System

A pulsed electron gun system has been developed for use with the Stanford superconducting accelerator and the free-electron laser. This report reviews the design and operating characteristics of the system and its components.     

The upgraded laser in vessel viewing system (IVVS) for ITER

A prototype of a laser in vessel viewing and ranging system was developed at ENEA laboratories in Frascati, it uses the amplitude modulated laser radar concept and it is conceived to withstand the severe ITER conditions. The in vessel viewing system (IVVS) probe has been designed and built to perform sub-millimetric three-dimensional images inside ITER; it is based on an intrinsically radiation resistant concept and architecture. A first characterization of the IVVS probe under room conditions was made at Frascati Labs on a full-scale mock-up of the ITER first wall panel (FWP) and of the divertor vertical target. The first characterization demonstrated that an upgrade of the IVVS performances was necessary especially to cope with divertor surfaces made of carbon material, which is highly absorbent from optical point of view.The paper describes the new developments of IVVS prototype to increase range measurement performances that was obtained increasing the modulation frequency, the optical efficiency of the probe optics and the laser power. A new test campaign has been carried out on the upgraded IVVS and a compact characteristic curve describing its performances has been found both in mathematical and graphical form. As far as viewing is concerned, the system has confirmed the sub-millimetric viewing resolution, reaching in the worst cases ～1 mm of resolution. The image quality was excellent in almost all the cases. The range measurement performance of IVVS system has been strongly upgraded reducing the standard deviation of range measure of a factor varying from 6 to 12. The increased performance allows measuring surface shapes and erosion on first wall tiles and divertor also for inclination angles completely outside the previous IVVS characteristics.     

鬼臼毒素及其衍生物的化学活性研究

动用脉冲辐解和激光光解技术，对鬼臼毒素及其衍生物的光学活性和化学活性进行了详细的研究。结果表明：它们不仅在激光作用扯具有很强的光敏性，而且还有多个活性基团分别与水合电子，氢原子，羟基自由基作用生成不同的瞬态粒子，且推断了相应的反应机理。为医学工作者进一步了解和利用反臼毒素，化学工作者合成更高抗肿瘤活性和低毒性物质提供参考。     

Temporal Change of Thermal Lens Effects on Highly Pumped Ytterbium Glass by Wavefront Measurement

The temporal change of thermal lens effects has been measured for the development of high efficient laser system. Ytterbium phosphate glass was used due to its high saturation fluence property. A free running flashlamp pumped Ti:sapphire laser was developed for the high energy pump source. Pumping intensity on the glass surface exceeded 800 kW/cm² which is enough high for laser diode simulator. Shack-Hartmann wavefront sensor system was applied to measure the thermal lens effects on a highly pumped ytterbium glass oscillator. The temporal change of wavefront was successfully measured at high repetition rate of 100 Hz. The measured wavefront were expanded to Zernike coefficients. Cooling process for the focus coefficient agreed well with the prediction of unsteady one dimensional heat conduction.     

Laser-RF synchronization based on digital phase detector

Laser oscillator synchronization with RF reference signal is ultra-important for a modem light source based on the accelerator.For Tsinghua Thomson scattering X-ray source,we have synchronized the mode-locked laser oscillator to RF reference signal with 48.2 fs RMS relative jitter.Both fundamental and harmonic signals derived from photo diode detection are used for laser-RF synchronization in our scheme.The fundamental signal is for coarse laser-RF synchronization and multiple laser oscillator synchronization.The harmonic signal is for high precise phase locking.The digital phase detector is implemented in the synchronization scheme for less noise,replacing the mixing to DC phase detection scheme.The digital processing algorithm for synchronization is commonly used in low-level RF control field.In order to test the phase locking loop logic without damaging the real laser oscillator,a laser oscillator emulator was developed for phase locking.This paper will report the laser-RF synchronization scheme and its performance.The laser oscillator emulator system will also be introduced here.