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Broadband isolated attosecond pulse generation in a two-color laser field combined with an orthogonally polarized laser pulse

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Science China(Physics,Mechanics & Astronomy) 2012年第1期55卷 1-6页

作者： DU HongChuan WANG XiaoShan hu bitao School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 China

We present a method to generate broadband isolated attosecond pulses. Using a two-color laser field, which is synthesized by a mid-infrared （12.5 fs, 2000 nm） and a weaker （12 fs, 800 nm） pulse in the x direction, a modulated supercontinuum from 290 to 430 eV is obtainable. By properly adding a second-harmonic control field of the driving pulse in the y direction, the short quantum path is well selected and a smooth supercontinuum from 290 to 440 eV is generated. The bandwidth of the supercontinuum can be controlled by adjusting the electric field of the control pulse in the x direction. When the electric field increases to 0.051 a.u., a smooth supercontinuum from 295 to 520 eV is obtained. Using this method we expect that isolated 63-as attosecond pulses with tunable central wavelengths are straightforwardly *** present a method to generate broadband isolated attosecond pulses. Using a two-color laser field, which is synthesized by a mid-infrared （12.5 fs, 2000 nm） and a weaker （12 fs, 800 nm） pulse in the x direction, a modulated supercontinuum from 290 to 430 eV is obtainable. By properly adding a second-harmonic control field of the driving pulse in the y direction, the short quantum path is well selected and a smooth supercontinuum from 290 to 440 eV is generated. The bandwidth of the supercontinuum can be controlled by adjusting the electric field of the control pulse in the x direction. When the electric field increases to 0.051 a.u., a smooth supercontinuum from 295 to 520 eV is obtained. Using this method we expect that isolated 63-as attosecond pulses with tunable central wavelengths are straightforwardly obtained.

关键词： HHG supercontinuum attosecond pulses

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Isolated attosecond pulse generation combining propagation effects and a modulated chirped polarization gating technique

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Science China(Physics,Mechanics & Astronomy) 2013年第5期56卷 888-895页

作者： DU HongChuan LUO LaoYong WANG XiaoShan hu bitao School of Nuclear Science and Technology Lanzhou University

We propose a theoretical scheme to generate a broadband supercontinuum using a modulated chirped polarization gating technique. By this technique, a broadband continuum of 155 eV can be obtained at microscopic level. The modulations on the supercontinuum can be eliminated after propagation. Then a smooth broadband supercontinuum with the bandwidth of 155 eV can be generated. As a result, isolated sub-100-attosecond pulses with tunable central wavelengths could be obtained straightforwardly. Our simulations also reveal that an isolated attosecond pulse can still be generated by using multicycle driving laser pulses, and the central wave- length of isolated attosecond pulse can be controlled by adjusting the delay rj （ra is the delay of the two counter-rotating circularly polarized pulses.）.

关键词： HHG supercontinuum attosecond pulse

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Monte Carlo simulation of GEM-based for 14 MeV neutron detector

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Science China(Physics,Mechanics & Astronomy) 2013年第9期56卷 1740-1744页

作者： WANG XiaoDong ZHANG YuLian ZHANG Chunhui hu bitao School of Nuclear Science and Technology Lanzhou University

A new concept of neutron detector based on Gas Electron Multiplier(GEM) technology is presented in this paper,in which a novel multi-layer high density polyethylene(HDPE) as neutron-to-proton converter is proposed and studied with Geant4 toolkit for fast 14 MeV *** preliminary results show that the detection efficiency of the detector with 400 converter units is higher than 2.3% and reconstruction accuracy of the incident neutron position is higher than 2.6%.

关键词： gas electron multiplier 14 MeV neutron detection efficiency position reconstruction

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Digital coincidence acquisition applied to portable β liquid scintillation counting device

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Nuclear Science and Techniques 2013年第3期24卷 45-49页

作者： REN Zhongguo hu bitao ZHAO Zhiping LI Dongcang School of Nuclear Science and Technology Lanzhou University China Academy of Engineering Physics

A digital coincidence acquisition system applied to a portable liquid scintillation counting device is developed. The system which simplifies the device design consists of a digitizer card of Agilent U1066A DC438, a discriminator and a host computer. The anode analog pulses from two photomultiplier tubes are captured by the system, which adopts the sequence acquisition storage mode. By choosing proper threshold for each channel, coincidence time window of ±30 ns, and comparing the pulse amplitudes from two channels, the portable scintillation counting device can be used to detect β particles. For the unquenched standard 3 H sample, the results show that the detection efficiency is (58.5±0.1)% and the background is (86.7±0.7) cpm. Meanwhile, 3 H β spectrum is obtained.

关键词：计数装置液体闪烁便携式采集系统收购应用脉冲幅度检测效率

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A stopping layer concept to improve the spatial resolution of gas-electron-multiplier neutron detector

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Chinese Physics B 2022年第5期31卷 225-230页

作者： Jianjin Zhou Jianrong Zhou Xiaojuan Zhou Lin Zhu Jianqing Yang Guian Yang Yi Zhang Baowei Ding bitao hu Zhijia Sun Limin Duan Yuanbo Chen School of Nuclear Science and Technology Lanzhou UniversityLanzhou 730000China Spallation Neutron Source Science Center Dongguan 523803China State Key Laboratory of Particle Detection and Electronics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

In recent years,gas electron multiplier(GEM)neutron detectors have been developing towards high spatial resolution and high dynamic counting *** propose a novel concept of an Al stopping layer to enable the detector to achieve sub-millimeter(sub-mm)spatial *** neutron conversion layer is coated with the Al stopping layer to limit the emission angle of ions into the drift *** short track projection of ions is obtained on the signal readout board,and the detector would get good spatial *** spatial resolutions of the GEM neutron detector with the Al stopping layer are simulated and optimized based on Geant4 Garfield *** spatial resolution of the detector is 0.76 mm and the thermal neutron detection efficiency is about 0.01%when the Al stopping layer is 3.0μm thick,the drift region is 2 mm thick,the strip pitch is 600μm,and the digital readout is ***,the GEM neutron detector with a simple detector structure and a fast readout mode is developed to obtain a high spatial resolution and high dynamic counting *** could be used for the direct measurement of a high-flux neutron beam,such as Bragg transmission imaging,very small-angle scattering neutron detection and neutron beam diagnostic.

关键词： high spatial resolution Al stopping layer GEM neutron detector spallation neutron source

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低能高电荷态离子U^(q+)在金属Al(111)表面掠射产生沟道效应的计算机模拟

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核技术 2005年第5期28卷 337-341页

作者：胡碧涛宋玉收兰州大学物理学院原子核研究所兰州730000

用自己编写的STARF程序,系统地研究了低能高电荷态离子uq+(q=10-40)在Al(111)晶面上掠射时,反射系数、反射离子的角分布等对于离子入射角、电荷态和能量的依赖关系;并探讨了高电荷态离子在金属表面产生沟道效应的条件。

关键词：沟道效应低能高电荷态离子掠射镜像电荷

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Controlling nonadiabatic spectral redshift of high-order harmonic using two orthogonally polarized laser fields

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Chinese Optics Letters 2018年第4期16卷 11-15页

作者： Hongmei Wu Shengjun Yue Jinbin Li Silin Fu bitao hu Hongchuan Du School of Nuclear Science and Technology Lanzhou University Lanzhou 730000 China Key Laboratory of Special Function Materials and Structure Design Ministry of Education Lanzhou University Lanzhou 730000 China

We investigate the nonadiabatic spectral redshift of high-order harmonic of He driven by two time-delayed orthogonally polarized laser fields. It is found that the nonadiabatic spectral redshift can be observed by properly adjusting the time delay of the two laser fields when the controlling pulse is added in the raising part of the driving pulse in the vertical direction. That is because the controlling pulse in the vertical direction prevents the ionized electrons from returning to the vicinity of parent ions and then reduces the recombination probability. This leads to the high-order harmonic generated mainly in the falling part of the driving pulse. Meanwhile,we also find that the quantity of redshift can be effectively controlled through accommodating the positive time delays. In addition, this scheme can also be used to produce nonadiabatic spectral blueshift.

关键词： Controlling nonadiabatic spectral redshift of high-order harmonic using two orthogonally polarized laser fields

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基于极化氦三靶的原子核散射实验

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原子核物理评论 2019年第2期36卷 151-160页

作者：张毅胡碧涛兰州大学核科学与技术学院兰州730000 兰州大学中子应用技术教育部工程研究中心兰州730000

利用极化的氦三气体靶可以显著地拓展传统的核物理实验研究,观察初态自旋自由度对核反应过程动力学的影响。本文通过列举极化三体核力实验以及极化的重离子电荷交换反应实验,介绍了极化氦三靶在核物理实验研究中的独特优势。在质子散射... 详细信息

利用极化的氦三气体靶可以显著地拓展传统的核物理实验研究,观察初态自旋自由度对核反应过程动力学的影响。本文通过列举极化三体核力实验以及极化的重离子电荷交换反应实验,介绍了极化氦三靶在核物理实验研究中的独特优势。在质子散射实验中,通过测量不同极化方向下的多种末态产物角分布,可以进一步检验手征有效场理论对于三体核力的描述;而在与重离子的电荷交换反应中,通过控制靶极化方向可以分离π介子交换与ρ介子交换对于核子自旋同位旋激发的贡献,从而为研究核子在不同核环境中的动力学演化提供独一无二的契机。结合我国新一代大科学装置的建设背景,尤其是以加速器驱动嬗变系统(ADS)和强流重离子加速器装置(HIAF)和中国散裂中子源(CNS)为代表的先进实验平台为原子核物理实验研究提供了理想的机遇。新的实验技术手段将明显拓展在这些大型核科学装置上开展实验研究的深度与广度。极化氦三靶做为其中具有独特优势的研究手段,必将具有广阔的应用前景。

关键词：极化氦三靶三体核力弹性散射电荷交换反应自旋-同位旋激发

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基于GEM工艺的裂变时间投影室性能模拟研究

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原子能科学技术 2020年第6期54卷 998-1004页

作者：赵鑫魏康刘昊胡碧涛张毅兰州大学核科学与技术学院甘肃兰州730000 兰州大学中子应用技术教育部工程研究中心甘肃兰州730000

基于GEM工艺的裂变时间投影室具有探测效率高和空间分辨率高的特点,可实现裂变产物的多参量测量.本文主要研究基于GEM工艺的裂变时间投影室在不同条件下的测量精度,使用Garfield++软件计算得到裂变时间投影室中不同的裂变产物质量数测... 详细信息

基于GEM工艺的裂变时间投影室具有探测效率高和空间分辨率高的特点,可实现裂变产物的多参量测量.本文主要研究基于GEM工艺的裂变时间投影室在不同条件下的测量精度,使用Garfield++软件计算得到裂变时间投影室中不同的裂变产物质量数测量误差约为4-6u,并通过时间信息的径迹重建研究了裂变碎片在不同工作气体中的角度分辨.研究发现,电子漂移时间长的工作气体中,裂变产物具有更好的角度分辨,并可依此在实验中选择合适的工作气体、气压和漂移电场强度来进行裂变碎片的测量.

关键词：裂变时间投影室 GEM 电子漂移径迹重建

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Energy loss、electron emission and X-Ray emission of low energy ions Arq+ grazing on the Al(111) surface

Energy loss、electron emission and X-Ray emission of low ene...

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第十五届全国原子与分子物理学术会议

作者： Xianwen.Luo,Jijin.Wang,chunhua.chen,Jian.Zhang and bitao.hu School of Nuclear Science and Technology,Lanzhou University,Lanzhou,730000

Ar ions grazing on the Al(111) surface has been simulated,The energy loss due to the charge exchange,happening before ions hitThe Al(111) surface,is *** emission resulting from kinetic and potential electron emission,and total electron yieldγand X-Ray emission as a function of crystal azimuthal orientation,is *** present simulation shows that the energy loss-、electron emission and X-Ray emission depend on the lattice orientation of Al(111) surface.

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