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为探索激光在束流截面测量上的应用,在北京正负电子对撞机二期工程(BEPCⅡ)的负电子传输线上建立了激光扫描系统。研究了激光扫描测量束流截面的相关计算方法。对激光和电子束相互作用、光子在介质中的切伦科夫辐射等过程进行了GEANT4模拟。对脉冲激光器进行了调试,测量了激光的脉宽、尺寸、功率等各项参数。设计并搭建了激光扫描系统的光路,编写了激光系统的机械扫描部件的控制软件。搭建了用于探测康普顿光子的契伦科夫探测器系统。激光的扫描、控制、以及激光参数的在线监测等系统工作正常,能满足激光扫描实验需要。 相似文献
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何俊张丛邓庆勇汪林随艳峰岳军会曹建社 《强激光与粒子束》2015,(6):282-287
为探索激光在束流截面测量上的应用,在北京正负电子对撞机二期工程(BEPCⅡ)的负电子传输线上建立了激光扫描系统。研究了激光扫描测量束流截面的相关计算方法。对激光和电子束相互作用、光子在介质中的切伦科夫辐射等过程进行了GEANT4模拟。对脉冲激光器进行了调试,测量了激光的脉宽、尺寸、功率等各项参数。设计并搭建了激光扫描系统的光路,编写了激光系统的机械扫描部件的控制软件。搭建了用于探测康普顿光子的契伦科夫探测器系统。激光的扫描、控制、以及激光参数的在线监测等系统工作正常,能满足激光扫描实验需要。 相似文献
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为探索激光在束流截面测量上的应用,在北京正负电子对撞机二期工程(BEPCⅡ)的负电子传输线上建立了激光扫描系统。研究了激光扫描测量束流截面的相关计算方法。对激光和电子束相互作用、光子在介质中的切伦科夫辐射等过程进行了GEANT4模拟。对脉冲激光器进行了调试,测量了激光的脉宽、尺寸、功率等各项参数。设计并搭建了激光扫描系统的光路,编写了激光系统的机械扫描部件的控制软件。搭建了用于探测康普顿光子的契伦科夫探测器系统。激光的扫描、控制、以及激光参数的在线监测等系统工作正常,能满足激光扫描实验需要。 相似文献
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《光子学报》2018,(11)
契伦科夫荧光的宽谱特性带来的组织光学特性差异导致传统的光传输模型的简化球谐函数近似和扩散方程无法兼顾准确度和效率,为了解决该问题,采用基于自适应混合简化球谐波近似-扩散方程的光传输模型作为多光谱契伦科夫荧光断层成像的前向模型.该模型利用组织光学特性参数自适应地选择合适的方程描述光在生物组织中的传输,充分发挥传统光传输模型各自的优势,以提供准确性和效率之间的平衡.通过简单规则几何实验和数字鼠实验验证所提出模型的准确性和效率.实验结果表明,与简化球谐近似模型相比,所提模型具有相同的准确度和更少的计算时间,与扩散方程模型相比具有更高的准确度,与简化球谐波近似-扩散方程的简单组合模型相比具有更好的自适应能力,适合作为多光谱契伦科夫荧光断层成像的光传输模型. 相似文献
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本文讨论了气体探测器在下述领域的最新应用:放射性痕量元素的二维图像;用X 射线衍射研究晶体结构;工业射线照相法;用核扩散的射线照相;契伦柯夫环探测器;流光管量热计;渡越辐射测量;用作电磁量热计的高密度显像室;用作探测契伦柯夫环的显像室。 相似文献
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给出双介质片平面波导契伦科夫自由电子激光波导模式的色散关系,求出器件的单程增益并证明存在一组新的波导模式__奇模。讨论了器件的工作频率和单程增益随介质片厚度、电子束能量和电子束通道宽度的变化关系。还研究了这组奇模对器件的影响。 相似文献
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介绍北京组新近提出的“Ca2F2(Eu) 液闪”复俣WIMP探测器的设计特点。通过对探测器单元内部光收集效率的研究,初步确定了复合探测器的设计结构。另外,对探测器内部放射性杂质衰变在复合探测器单元中形成的本底情况进行模拟,结果表明了复合探测器具有良好的排除本底的能力。 相似文献
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In this study, we characterized Cerenkov radiation generated in polystyrene (PS)- and polymethyl methacrylate (PMMA)-based plastic optical fibers (POFs) to select an adequate optical fiber for producing Cerenkov radiation. To determine the relationship between the absorbed dose and the intensity of Cerenkov radiation, we calculated the energy depositions of photon beams and fluxes of electrons inducing Cerenkov radiation using the Monte Carlo N-Particle eXtended code. Also, intensities of Cerenkov radiation generated in PS- and PMMA-based POFs were measured as functions of dose rate and monitor unit. At last, therapeutic photon beams-induced Cerenkov radiation in PS- and PMMA-based POFs was measured according to depths of solid water phantom. 相似文献
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To theoretically explore the feasibility of neutron dose characterized by Cerenkov photons, the relationship between Cerenkov photons and neutron dose in a water phantom was quantified using the Monte Carlo toolkit Geant4. Results showed that the ratio of the neutron dose deposited by secondary electrons above Cerenkov threshold energy to the total neutron dose is approximately a constant for monoenergetic neutrons from 0.01 eV to 100 eV. With the initial neutron beam energy from 0.01 eV to 100 eV, the number of Cerenkov photons has a good correlation with the total neutron dose along the central axis of the water phantom. The changes of neutron energy spectrum and mechanism analysis also explored at different depths. And the ratio of total neutron dose to the intensity of Cerenkov photons is independent of neutron energy for neutrons from 0.01 eV to 100 eV. These findings indicate that Cerenkov radiation also has potential in the application of neutron dose measurement in some specific fields. 相似文献
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针对现有核素治疗中内照射剂量测量缺乏简单、高效方法的问题,基于内照射剂量与切伦科夫辐射之间的关系,提出一种基于切伦科夫辐射的核素治疗内照射剂量测量的新方法。利用蒙特卡罗计算程序Geant4,模拟放射性核素131I在水体模型和甲状腺模型中产生切伦科夫辐射与剂量沉积的分布情况,并定量分析切伦科夫光子数与剂量之间的关系。计算结果表明:在水体模的半径方向上切伦科夫光子数与剂量之间有着相同的变化趋势,且两者有着相同的二维分布规律;核素131I在介质中产生的切伦科夫光子数与剂量两者之间存在一定的线性关系,且这种线性关系与核素的分布情况无关。研究结果证实,将这种放射性核素在介质中产生的切伦科夫辐射应用于内照射剂量学具有非常大的研究潜力和价值。 相似文献
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De Groot J.S. Stone R.A. Mizuno K. Rogers J.H. Pointon T.D. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1988,16(2):206-216
The linear and nonlinear theory of the efficient operation of high-power (gigawatt) and superpower (50 GW) Cerenkov masers is presented. Issues such as breakdown, plasma production, and coupling to the output device are discussed. The relative merits of dielectric Cerenkov masers and plasma Cerenkov masers are considered. The principal design tool is a new particle simulation model that was developed to investigate Cerenkov masers. The novel aspects of this model are briefly described along with a comparison of calculated and experimental results. The agreement between calculations and measurements is generally good. Designs for a high-power and superpower plasma Cerenkov masers are also described 相似文献
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Raj Gandhi Kamales Kar S. Uma Sankar Abhijit Bandyopadhyay Rahul Basu Pijushpani Bhattacharjee Biswajoy Brahmachari Debrupa Chakraborti M. Chaudhury J. Chaudhury Sandhya Choubey E. J. Chun Atri Desmukhya Anindya Datta Gautam Dutta Sukanta Dutta Anjan Giri Sourendu Gupta Srubabati Goswami Namit Mahajan H. S. Mani A. Mukherjee Biswarup Mukhopadhyaya S. N. Nayak M. Randhawa Subhendu Rakshit Asim K. Ray Amitava Raychaudhuri D. P. Roy Probir Roy Suryadeep Roy Shiv Sethi G. Sigl Arunansu Sil N. Nimai Singh Mark Vagins Urjit Yagnik 《Pramana》2003,60(2):405-409
This is the report of neutrino and astroparticle physics working group at WHEPP-7. Discussions and work on CP violation in
long baseline neutrino experiments, ultra high energy neutrinos, supernova neutrinos and water Cerenkov detectors are discussed. 相似文献
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We study nonlinear Cerenkov radiation generated from a nonlinear photonic crystal waveguide where the nonlinear susceptibility tensor is modulated by the ferroelectric domain. Nonlinear polarization driven by an incident light field may emit coherently harmonic waves at new frequencies along the direction of Cerenkov angles. Multiple radiation spots with different azimuth angles are simultaneously exhibited from such a hexagonally poled waveguide. A scattering involved nonlinear Cerenkov arc is also observed for the first time. Cerenkov radiation associated with quasi-phase matching leads to these novel nonlinear phenomena. 相似文献
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本文用磁流体理论研究了柱形波导填充等离子体的切伦柯夫自由电子激光器,表明该系统比普通切伦柯夫自由电子激光具有更高的工作频率和线性增长率。发现在入射电流和波导结构一定时,该系统和普通切伦柯夫自由电子激光器的增长率并不是随随电子束与介质的间距的增加而减小,而是存在一个最佳值。 相似文献
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Kyoung Won Jang Wook Jae Yoo Jeong Ki Seo Ji Yeon Heo Jinsoo Moon Jang-Yeon Park Sin Kim Byung Gi Park Bongsoo Lee 《Optical Review》2011,18(1):176-179
In this study, we measured scintillating and Cerenkov lights generated in a scintillating fiber-optic sensor using highenergy
electron beams and a spectrometer. The spectrum of Cerenkov light generated in a plastic optical fiber was measured with a
spectrometer and the intensities of Cerenkov light were measured for irradiated lengths of the plastic optical fiber by integrating
the photon counts at every wavelength of the spectrum. The intensities of Cerenkov and scintillating lights were also characterized
as a function of the incident angle of an electron beam from a clinical linear accelerator (CLINAC). To minimize or remove
Cerenkov light, a subtraction method was employed using a background optical fiber. 相似文献