Study of Photon Discrimination of PHOS

The PHOS which in ALICE is to detect and identify real photons and measure with high resolution their 4-momentum with the prospect to perform the physics programs exploiting direct photon and light neutral mesons as privileged probes. The PHOS is composed…     

Calculation of Transverse Acceptance of CYCIAE-100

The acceptance of central region should be considered after the central ray is finished. This can check whether the central region design is reasonable or not, because in practice it is the bunched beam     

Study of Fine Structure of Λ Hyper-nuclei

The energy levels of p-shell hyper-nuclei Λ7Li, Λ9Be and 1Λ6O are investigated using the Hyperball spectrometer with energy resolutions of a few keV at KEK and AGS.A complete bound state level scheme of Λ7Li is established. The strength of the ΛN spi     

Trial Manufacture of Core Subassemblies of CEFR

Engineering department of CEFR selected factories to research manufacturing process of subassemblies in March 2001. By November 2001, the trial productions of several materials have been completed. Meanwhile two B4C shielding subassemblies and two support legs of steel reflecting subassembly, which are used in hydrodynamic and structural stability out-of-pile tests, and three B4C rods which are irradiated in-pile have been assembled.     

Calculation of Transverse Acceptance of CYCIAE-100

CARR燃料组件是板状元件，共有21块燃料板和20个矩形冷却流道。流道宽度不均匀，从外到内分别有2．59、2．45、2．32和2．20mm4种宽度，长度均为66．6mm。燃料组件的主要特点是热流密度高、传热性能好。良好的组件流量分配特性是充分发挥这些优点的重要保障。对于这种窄缝流道的水力特性和流量分配实验，国内外均进行不多，加之结构复杂，流速很高，因此，很有必要对它们进行实验验证。     

Study of SEU Sensitive Volume of Microelectronic Devices

It is important to determine the sensitive volume (Sv) thickness of micro-electronic devices, since the Sv thickness is a key parameter for estimating single event rates in space. Most of the models for proton single event upset (SEU) predictions use the …     

Simulation of storage ring injection of HLS Ⅱ

The Hefei light source(HLS) has been upgraded into HLS II, with increased brightness and stability. In this paper, the new injection system is described. Elegant program is used to simulate the particles motion in 6D phase space. In the process of tracking simulation of electrons, the system tolerances and magnet errors are introduced. Influences to the injection efficiency from beam injection deviation are studied. These provide important reference for realizing the Top-up injection.     

Activation γ-Spectrometric Method of Determining the Mass of Samples of Nuclear Materials

The possibility of using activation -spectrometry to determine the mass content of nuclear materials in matter is investigated. Irradiation of samples for a short time with moderated neutrons from a ~10⁷ sec^–1 Pu–Be source is used to induce 1436 keV -ray emission from ¹³⁸Cs. These -rays are suitable for measurements; the mass of the nuclear materials is determined from the intensity of the radiation. Three series of experiments are performed with sets of samples consisting of uranium and uranium dioxide with different mass and degrees of enrichment.Experiments showed that the error in determining the mass of uranium samples can reach 1–3% with 30–60 min irradiation and the same measurement duration.Special experiments were performed to investigate the influence of the experimental geometry and the self-absorption of the rays in the sample, which limit the possibility of -spectrometric measurements on samples of nuclear materials.The activation -spectrometric method can be used for analyzing metallic uranium samples, powder samples, samples of fuel micropellets and uranium hexafluoride, and plutonium samples.     

Verification of the Extrapolating Critical Programme of CEFR

The extrapolating critical program is an important sub-program of the CEFR’s physical startup software. After the physics startup software is finished, each of the sub-program is verified separately. This text will do a brevity presentation about the cou…     

Determination of Dead Time of Neutron Counting System for Use of Reactor Start up

The dead time is important parameter of neutron counting system for use of reactor start up. It isrelative to accurate determination of critical mass and the safety during reactor start up. So, it is importantthat dear time is measured accurately. There are many methods for measuring the dead time, but they arerare to be suitable for neutron counting system, which has wide variant range. Using the reactor as the neutron source, the neutron source intensity and the curve of counting rate,     

Verification of the Extrapolating Critical Programme of CEFR

The extrapolating critical program is an important sub-program of the CEFR＇s physical startup software. After the physics startup software is finished, each of the sub-program is verified separately. This text will do a brevity presentation about the course of verification off-line for extrapolating critical program     

Plasma properties of pulsed laser ablation of GaAs

Simultaneous time and space-resolved emission spectrum from a Nd:YAG laser-ablated plasma on a GaAs target has quantitative information on the generation and the propagation of species in the plasma at 1 atm or lower pressures.The experimental results show that the characteristics of the species in plasma are strongly influenced by the ambient pressure.The time-of-flight distributions of Ga atoms exhibit twin-peak structure,which can be explained by recombination process.The mean projected ranges of As^ ions in the atmosphere of different densities were calculated according to Ziegler‘ theory model and the slowing down processes of them were simulated by using a Monte Carlo simulation program TRIM80,The calculatedc results are consistent with the experimental.