固体气泡损伤探测器中子探测效率的刻度

在２＊１．７ＭＶ串列加速器上用＾７Ｌｉ（ｐ,ｎ）＾７Ｂｅ、Ｔ（ｐ,ｎ）＾３Ｈｅ、Ｄ（ｄ,ｎ）＾３Ｈｅ和Ｔ（ｄ,ｎ）＾４Ｈｅ核反应产生的２０ｋｅＶ－１９ＭｅＶ单能快中子对中国原子能科学研究院研制的固体气泡损伤探测器进行了刻度。这种探测器可用于中子能谱和中子剂量测量。     

氘团簇离子（d^＋3）与固体相互作用过程中的团簇行为研究

讨论了由三个氘原子组成的氘团簇离子束与独立氘离子束在轰击固体靶时,在原子过程呼Ｄ－Ｄ核聚变过程中体现出的差别。对氘团簇与固体靶相互作用的机理进行了分析。     

SIMS对氘靶钛膜中氘的分布研究

用负的ＳＩＭＳ分析技术进行Ｈ同位素相对含量Ｔｉ膜深度变化的分析，获得了氘随膜深度变化的分布曲线。在接近膜表面的一个深度范围内，除有明显的Ｏ＾－、ＣＯ＾－和很微弱的ＯＨ＾－，ＯＤ＾－及ＣＨＯ＾－峰谱外，还有很大的Ｄ＾－二次离子质谱峰，氘的丰度估计约为９８％。在靶膜内部，氘的丰度达９９％以上。     

^197Au束轰击TiD靶引起的D—D熔合研究

测量了能量范围从１．０ＭｅＶ到５．２ＭｅＶ的＾１９７Ａｕ束轰击ＴｉＤ靶引发的Ｄ（ｄ，ｐ）Ｔ反应的质子产额曲线，为了对其进行解释，根据两步级联磁撞模型的框架编写的ＴＳＣＣＦＣ程序进行了相应的计算，发现计算结果与结果在误差范围内能较好地符合。     

通过改变Si(Au)探测器灵敏区厚度鉴别带电粒子的方法及应用研究

重点研讨通过改变探测器偏压,进而改变探测器的ＰＮ结（有效探测灵敏区）厚度,实验对带电粒子的种类和能量鉴别的实验方法及其实际应用。实验测量了３ＭｅＶ质子和６．０５ＭｅＶα粒子在金硅面垒探测器Ｓｉ（Ａｕ）中的能损与探测器偏压关系曲线。同时利用刻度过的探测器鉴别氚离子束轰击氚钛（ＴｉＤｘ）靶发射的带电粒子能谱。在很强的本底情况下通过调节探测器偏压（灵敏区厚度）实现了对能量相近的不同带电粒子的有效鉴别和测     

惯性约束聚变靶材中间体氘代乙醛的合成与表征

氘代乙醛（ＣＤ３ＣＤＯ）是合成惯性约束聚变（ＩＣＦ）固体靶材料氘代聚苯乙烯（ＤＰＳ）的重要中间体之一。以电石（ＣａＣ２）及重水（Ｄ２Ｏ）为原料,经多步液－固,气－液化学反应,合成氘经达９９．２％,的氘代乙醛,介绍了氘代乙醛的合成工艺及其氘代率的表征方法,并对主要合成工艺参数等进行了探讨。     

氘—氚托卡马克等离子体中约束α分布的测量

在ＴＦＴＲ托卡马克氘－氚等离子体芯部，α密度为３×１０＾１６ｍ＾－３时，用光谱测量术观察了能量≤０．７ＭｅＶ的聚变产生的α粒子。在无锯齿放电期间，在ｒ／ａ＝０．３处所测得的能谱与基于碰撞输运所预计的能谱完全一致。在α源关闭之后，α热化期间时间分辨测量表明，分布函数衰减到较低能量是与经典慢化时间０．５ｓ一致的。     

^92Mo（n,p）^92Nb^m反应截面的测量和低能中子的扣除

用活化法相对标准反应测量了＾９２Ｍｏ（ｎ,ｐ）＾９１２Ｎｂ＾ｍ反应截面,其能区为５－１９ＭｅＶ。测量中分析了低能中子的影响,采用恰当的方法有效地扣除他们的干扰。特别是在１７－１９ＭｅＶ能区,用空靶扣除了Ｄ－ｄ低能中子的影响,得到了合理的截面走向。     

新疆电气石^60Coγ辐照变色研究

通过对新疆电气石用＾６０Ｃｏγ射线辐照、热处理可使之变以，应用ＸＲＤ、ＸＲＦ、吸收光谱实验，得出电气石改变颜色主要由ｂ位Ｆｅ＾２＋，Ｍｎ＾３＋电子的ｄ－ｄ跃迁相应的１３８００ｃｍ＾－１和１９５００ｃｍ＾－１谱所决定。 ＲＤ     

纳秒级d－T聚变反应的16．7MeVγ测量

ｄ－Ｔ聚变反应产生的１６７ＭｅＶγ射线很弱，必须从很强的γ、中于混合场中筛选出来，故要求探测系统有高的信噪比，快的时间响应和宽的动态范围。利用高能γ与介质相互作用的康普顿效应及其定量对应关系，由扇形聚焦磁场一次偏转，用ＣＯ２气体切连科夫探测器（ＧＣＤ）探测电子束，或由扇形聚焦磁场（ＳＣＤ）二次偏转，用有机玻璃切连科夫探测器测电子束。仔细考虑了探测装置的辐射屏蔽和探测系统的电磁屏蔽。分别在“闪光－１”装置、ＤＨＪ－２５回旋加速器和２ＭＶ直线加速器上对探测装置进行了模拟检验实验和标定实验。在实际测试中，首次获得了纳秒级ｄ－Ｔ聚变反应产生的１６７ＭｅＶγ波形。     

Evaluation of D(d,n)3 He reaction neutron source models for BNCT irradiation system design

A mathematical method was developed to calculate the yield,energy spectrum and angular distribution of neutrons from D(d,n)~3He(D-D)reaction in a thick deuterium-titanium target for incident deuterons in energies lower than 1.0MeV.The data of energy spectrum and angular distribution were applied to set up the neutron source model for the beam-shaping-assembly(BSA)design of Boron-Neutron-Capture-Therapy(BNCT)using MCNP-4C code. Three cases of D-D neutron source corresponding to incident deuteron energy of 1000,400 and 150 key were inves- tigated.The neutron beam characteristics were compared with the model of a 2.45 MeV mono-energetic and isotropic neutron source using an example BSA designed for BNCT irradiation.The results show significant differences in the neutron beam characteristics,particularly the fast neutron component and fast neutron dose in air,between the non-isotropic neutron source model and the 2.5 MeV mono-euergetic and isotropic neutron source model.     

Evaluation of D（d,n）^3 He reaction neutron source models for BNCT irradiation system design

A mathematical method was developed to calculatc the yield.energy spectrum and angular distribution of neutrons from D(d,n)3 He(D-D)reaction in a thick deuterium-titanium target for incident deuterons in energies lower than 1.0MeV.The data of energy spectrum and angular distribution wefe applied to set up the neutron source model for the beam-shaping-assembly(BSA)design of Boron-Neutron-Capture-Therapy(BNCT)using MCNP-4C code.Three cases of D-D neutron source corresponding to incident deuteron energy of 1000.400 and 150 kaV were investigated.The neutron beam characteristics were compared with the model of a 2.45 MeV mono-energetic and isotropic neutron source using an example BSA designed for BNCT irradiation.The results show significant differences in the neutron beam characteristics,particularly the fast neutron component and fast neutron dose in air,between the non-isotropic neutron source model and the 2.5 MeV mono-energetic and isotropic neutron source model.     

Physics design of a 70 MeV high intensity cyclotron, CYCIAE-70

This paper introduces the physics design of a 70 MeV high intensity cyclotron at China Institute of Atomic Energy (CIAE), which is aimed for multiple uses including radioactive ion-beam (RIB) production. The machine adopts a compact structure of four straight sectors, capable of accelerating two kinds of beams, i.e. H⁻ and D⁻ . The proton and deuteron beam will be extracted in dual opposite directions by charge exchange stripping devices. The energy of the extracted proton beam is in the range 35-70 MeV with an intensity up to 700 μA. The corresponding values for the deuteron beam are 18-33 MeV and 40 μA. This paper will present the main characteristics and parameters in the design of the 70 MeV cyclotron, the results of the basic beam dynamics study, as well as the physics in the design of the different systems, including the main magnet, RF, injection and extraction systems, etc.     

Basic information on new regulatory criteria requiring on-site emergency preparedness for accelerator facilities in Japan

For basic information on new regulatory criteria, the dose rate around a thick target bombarded by proton, electron, or carbon beam having incident energy of 10 MeV–50 GeV (per nucleon in case of carbon) was simulated using the PHITS Monte Carlo code. Based on this simulation, the benchmark which is ‘1 Sv/h at 1 m away from the beam line’ assuming 1% beam loss was evaluated, and compared with the criteria in France and Canada. Based on this evaluation, a new regulatory criteria has been established for requiring on-site emergency preparedness for accelerator facilities in Japan, which is required for the ion accelerator beyond the ion beam of 100 MeV/nucleon and 0.5 kW beam power, and the electron accelerator beyond the electron beam of 50 MeV energy and 1 kW beam power.     

A D-D neutron generator using a titanium drive-in target

A D-D neutron generator was developed with an intensity of 10⁸ n/s. A helicon plasma ion source was used to produce a large current deuteron beam, and neutrons were generated by irradiating the deuteron beam on a titanium drive-in target made of commercial pure titanium. The neutron generator was test-run for several hundred hours, and the performances were investigated. The available range of the deuteron beam current was 0.8-8 mA and the beam could be accelerated up to 97.5 keV. The maximum neutron generation rate in the test-runs was 1.9 × 10⁸ n/s, which was achieved by irradiating a 7.6 mA deuteron beam at 94.0 keV on a 0.5 mm-thick target. The operation of the neutron generator was fairly stable, such that the neutron generation rate was not altered by high voltage breakdowns during the test-runs. Neutron generation efficiency was rated as low as 10% when compared to an ideal case of irradiating a 100% monatomic deuteron beam on a perfect TiD₂ target. Factors causing the low efficiency were suggested and discussed.     

Extending Bragg peak of heavy ion beam and melanoma cell inactivation measurement

A rotating range modulator was designed and manufactured.which is applied to extend Bragg peak of heavy ion beam.Bragg curves of 75MeV/u ^16O and 75MeV/u ^12C ion beams through this range modulator were measured respectively and two evident spread-out Bragg peaks corresponding to the modulated beams above are shown.In addition,inactivation effect of the modulated 75MeV/u ^16O ion beam at nine different penetration depths on melanoma cells(B16) was measured.Results indicate that lethal effects at the spread-out Bragg peak region are larger than at the plateau of the particle beam entrance.     

Creation of microstructures using heavy ion beam lithography

In this work, three-dimensional (3D) structures were produced in PMMA and CR-39 polymer resists using a carbon ion microbeam. To investigate possible advantages of heavy ions compared to the well-established proton beam lithography, the same resist materials were also irradiated with protons that had a range in the materials studied here similar to that of carbon ions. The microstructures produced in different resists were analysed after chemical etching. The quality of the bottom and side walls of the structures produced by protons and carbon ions were compared using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results showed that, for the resist materials tested, lithographic structures made with the 8 MeV carbon beam had more rough lateral and bottom surfaces compared to those made with 0.6 MeV proton beam lithography.     

Cross-section for D(p,p)D elastic scattering from 1.8 to 3.2 MeV at the laboratory angles of 155° and 165°

The D(p,p)D cross-sections for elastic scattering of proton on deuterium over incident proton energy range from 1.8 to 3.2 MeV at both laboratory angles of 155° and 165° were measured. A thin solid state target Ni/TiD_x/Ta/Al used for cross-section measurement was fabricated by firstly depositing layers of Ta, Ti and Ni film on the Al foil substrate of about 7 μm in turn using magnetron sputtering and then deuterating under the deuterium atmosphere. The areal density of metal element in each layer of film was measured with RBS analysis by using a 4.0 MeV ⁴He ion beam, while the areal density of the deuterium absorbed in the Ti film was measured with ERD analysis by using a 6.0 MeV ¹⁶O ion beam. The results show that the cross-sections of p-D scattering under this experimental circumstance were much enhanced over the Rutherford cross-section value. It was found that the enhancement increases linearly as the energy of the incident beam increases. The total uncertainty in the measurements was less than 7.5%.     

Deuteron disintegration in condensed media

We discuss the Oppenheimer-Phillips process as a possible phenomenon leading to deuteron disintegration due to polarization in the Coulomb field of a target nucleus. This reaction may be possible in the context of electrochemically compressed deuterons in a palladium cathode. The process is exothermic and may lead to neutron capture from the deuterons into the palladium isotopes, as well as between the deuterons themselves. In the last case, the equivalent of the proton branch of the D-D fusion reaction occurs in preference to the neutron branch. Such a process could provide a model for the processes involved in the observed energy release and tritium production in conjunction with neutron suppression in recent experiments. Possible interactions with Be and fertile isotopes are discussed in the context of breeding fissile isotopes in subcritical configurations.