2010 Vol. 34, No. 3

Particle and field theory
Study of η and η´ physics at BES-Ⅲ
JI Qing-Ping, ZHANG Lei, CHEN Shen-Jian, LI Hai-Bo, LU Gong-Ru
2010, 34(3): 305-310. doi: 10.1088/1674-1137/34/3/001

Decays of both η and η´ provide very useful information in our understanding of low-energy QCD, and experimental signatures for these decays would be extremely helpful at BES-Ⅲ. The rare decays of the η and η´ mesons could serve as a low-energy test of the Standard Model and its beyond. The sensitivities of the measurements of η and η´ decays are discussed at BES-Ⅲ, in which the η and η´ mesons are produced in the ψ decays.

Testing Bell inequality at experiments of high energy physics
HAO Xi-Qing, KE Hong-Wei, DING Yi-Bing, SHEN Peng-Nian, LI Xue-Qian
2010, 34(3): 311-318. doi: 10.1088/1674-1137/34/3/002

Besides using the laser beam, it is very tempting to directly testify the Bell inequality at high energy experiments where the spin correlation is exactly what the original Bell inequality investigates. In this work, we follow the proposal raised in literature and use the successive decays J/ψ→γηc→ΛΛ→pπ+ to testify the Bell inequality. Our goal is twofold, namely, we first make a Monte-Carlo simulation of the processes based on the quantum field theory (QFT). Since the underlying theory is QFT, it implies that we pre-admit the validity of quantum picture. Even though the QFT is true, we need to find how big the database should be, so that we can clearly show deviations of the correlation from the Bell inequality determined by the local hidden variable theory. There have been some critiques on the proposed method, so in the second part, we suggest some improvements which may help to remedy the ambiguities indicated by the critiques. It may be realized at an updated facility of high energy physics, such as BES Ⅲ.

Scalar mesons and glueballs in Dp-Dq hard-wall models
WANG Chao, HE Song, HUANG Mei, YAN Qi-Shu, YANG Yi
2010, 34(3): 319-324. doi: 10.1088/1674-1137/34/3/003

We investigate the light scalar mesons and glueballs in the Dp-Dq hard-wall models, including D3-Dq, D4-Dq, and D6-Dq systems. It is found that only in the D4-D6 and D4-D8 hard-wall models are the predicted masses of the qq scalar meson f0 scalar glueball consistent with their experimental or lattice results. This indicates that D4-D6 and D4-D8 hard-wall models are the favorite candidates of the realistic holographic QCD model.

kth-order antibunching effect for a new kind of excited even and odd q-coherent states
2010, 34(3): 325-329. doi: 10.1088/1674-1137/34/3/004

A new kind of excited even q-coherent states (aq1)m|α〉qe and excited odd q-coherent states (aq-1 )m|α〉qo is constructed by acting with inverse boson operators on the even and odd q-coherent states. The m dependence of the kth-order antibunching effect is numerically studied for k=2, 3, 4, 5.It is shown that the kth-order antibunching effect enhances as m increases. The larger k, the quicker the antibunching effect enhances.

Topological structure of the solitons solution in SU(3) Dunne-Jackiw-Pi-Trugenberger model
LIU Zi-Yu, XIANG Qian-Lan, ZHANG Xiao-An, XIAO Guo-Qing
2010, 34(3): 330-333. doi: 10.1088/1674-1137/34/3/005

By using φ-mapping topological current theory and gauge potential decomposition, we discuss the self-dual equation and its solution in the SU(N) Dunne-Jackiw-Pi-Trugenberger model and obtain a new concrete self-dual equation with a δ function. For the SU(3) case, we obtain a new self-duality solution and find the relationship between the soliton solution and topological number which is determined by the Hopf index and Brouwer degree of φ-mapping. In our solution, the flux of this soliton is naturally quantized.

Nuclear and ion Physics
Systematic studies on α-decay half-lives for super heavy nuclei
ZHANG Di-Da, CHEN Bao-Qiu, MA Zhong-Yu
2010, 34(3): 334-339. doi: 10.1088/1674-1137/34/3/006

Radioactive decay of super heavy nuclei via the emission of α-particles has been studied theoretically in the preformed cluster model (PCM). The nucleus-nucleus (NN) potential is obtained by double folding the density distributions of the α-particle and the daughter nucleus with a realistic effective interaction. The M3Y effective interaction, supplemented by a zero-range pseudo-potential for exchange term, is used to calculate the NN potential. The α decay half-lives for 317 nuclei at Z=102—120 are performed in the PCM framework with the theoretical Q values extracted from the Möller-Nix-Kratz and Liran-Marinov-Zeldes mass tables and are compared with the experimental data. The calculated results are also compared with those obtained by using Q values from the Muntian-Hofmann-Patyk-Sobiczewski and Myers-Swiatecki mass estimates.

Multiparticle azimuthal correlations in central nucleus-nucleus collisions at high energy
SHAO Gui-Cheng
2010, 34(3): 340-343. doi: 10.1088/1674-1137/34/3/007

Multiparticle azimuthal correlations in central nucleus-nucleus collisions at high energy are described by a simple formula. The calculated results are in agreement with the experimental data of carbon and oxygen induced interactions at Dubna energy. The comparison between the calculated results and experimental data shows that particles are emitted isotropically in the rest frame of the emission sources, and the emission sources have movements in momentum space.

Detection Technology and Methods
Calibration of RPC-based muon detector at BESⅢ
XIE Yu-Guang, LI Wei-Dong, LIANG Yu-Tie, YOU Zheng-Yun
2010, 34(3): 344-353. doi: 10.1088/1674-1137/34/3/008
The calibration algorithm for RPC-based muon detector at BESⅢ has been developed. The calibration method, calibration error and algorithm performance are studied. The primary results of efficiency and noise at layer, module and strip levels have been calibrated with cosmic ray data. The calibration constants are available for simulation and reconstruction tuning. The results of Monte Carlo and data are also compared to check the validation and reliability of the algorithm.
Properties study of ZnO:Ga crystal on pulsed radiation detections
MA Yan-Liang, OUYANG Xiao-Ping, ZHANG Jing-Wen, ZHANG Zhong-Bing, PAN Hong-Bo, CHEN Liang, LIU Lin-Yue
2010, 34(3): 354-358. doi: 10.1088/1674-1137/34/3/009

In this paper, properties on pulsed radiation detections of ZnO:Ga crystal grew by a magnetron sputtering method were studied. The time response to pulsed laser, pulsed hard X rays and single α particles, the energy response to pulsed hard X ray, the scintillation efficiency to γ rays, the response to pulsed proton, and the relations of the light intensity varied with the proton energy were measured and analyzed in detail. Results show that the ZnO:Ga crystal has potential applications in the regime of pulse radiation detection.

A simulation study of the e+/e sensitivity of a low resistive phosphate glasselectrode in a RPC using GEANT MC
J. T. Rhee, Y. J. Jeon
2010, 34(3): 359-362. doi: 10.1088/1674-1137/34/3/010

The resistivity of conventional glass is quite high and is unacceptable in a high
rate environment. Low resistive glass-electrodes could be a solution for this problem. The present study reports the e+/e simulation results of an RPC detector made from low resistive phosphate glass electrodes. The detailed geometrical configuration of the content materials which are the essential components of the glass of the RPC detector have been created with the GEANT4 simulation code. Two different types of particle sources, i.e. for e+/e, have been located on the detectors surface to evaluate the performance of the phosphate glass RPC. Both of the particles have been simulated as a function of their respective energies in the range of 0.1 MeV—1.0 GeV. The present simulation work has shown that the resistive electrode plays an important role for the particle production in the RPC configuration.

Secondary electron time detector for mass measurements at CSRe
TU Xiao-Lin, WANG Meng, HU Zheng-Guo, XU Hu-Shan, GUO Zhong-Yan, MAO Rui-Shi, XIAO Guo-Qing, ZHANG Hong-Bin, ZANG Yong-Dong, YUE Ke
2010, 34(3): 363-367. doi: 10.1088/1674-1137/34/3/011

The Isochronous Mass Spectrometry is a high accurate mass spectrometer. A secondary electrons time detector has been developed and used for mass measurements. Secondary electrons from a thin carbon foil are accelerated by an electric field and deflected 180° by a magnetic field onto a micro-channel plate. The time detector has been tested with alpha particles and a time resolution of 197 ps (FWHM) was obtained in the laboratory. A mass resolution around 8×10-6 for Δm/m was achieved by using this time detector in a pilot mass measurement experiment.

BESⅢ barrel time-of-flight (TOF) calibration using cosmic ray data
YAN Jie, SUN Sheng-Sen, LI Cheng, HE Kang-Lin
2010, 34(3): 368-373. doi: 10.1088/1674-1137/34/3/012

The principle of the method for the BESⅢ TOF calibration using cosmic ray data without magnetic field are reported in this paper. After applying calibration constants, the single-end readout time resolution could reach about 150 ps, and the time resolution for one layer is achieved to be about 110 ps. The paper also described the extraction scheme for the event start time of cosmic events.

Histogram comparison used in BESⅢ software and data validation
YAO Jian, JI Xiao-Bin, LI De-Min
2010, 34(3): 374-378. doi: 10.1088/1674-1137/34/3/013

The performance of histogram comparison is studied for the various types of hypothesis test methods. The Kolmogorov test is recommended for the software and data validation and the minimum event numbers for different distributions are given in order to get more reliable results. A new bin content comparison method is implemented to deal with the hitmap-like histograms.

Investigation of add-back effects in a segmented Clover detector
WANG Hua-Lei, SONG Li-Tao, ZHAO Wei-Juan, LIU Zhong-Xia, ZHANG Yu-Hu, ZHOU Xiao-Hong, GUO Ying-Xiang, LEI Xiang-Guo
2010, 34(3): 379-382. doi: 10.1088/1674-1137/34/3/014

The resolution and the summing characteristics of an EXOGAM segmented Clover germanium detector has been studied for use it in γ spectroscopic experiments. The measurements have been performed with standard radioactive sources of 152Eu, 133Ba and β-delayed γ-rays from 176Ir decay. The data analytic results, realized by software, are presented in this paper.

ATPF—a dedicated proton therapy facility
FANG Shou-Xian, GUAN Xia-Ling, TANG Jing-Yu, CHEN Yuan, DENG Chang-Dong, DONG Hai-Yi, FU Shi-Nian, JIAO Yi, SHU Hang, OUYANG Hua-Fu, QIU Jing, SHI Cai-Tu, SUN Hong, WEI Jie, YANG Mei, ZHANG Jing
2010, 34(3): 383-388. doi: 10.1088/1674-1137/34/3/015

A proton therapy facility based on a linac injector and a slow-cycling synchrotron is proposed. To obtain good treatments for different cancer types, both the spot scanning method and the double-scattering method are adopted in the facility, whereas the nozzles include both gantry and fixed beam types. The proton accelerator chain includes a synchrotron of 250 MeV in maximum energy, an injector of 7 MeV consisting of an RFQ and a DTL linac, with a repetition rate of 0.5 Hz. The slow extraction using the third-order resonance and together with the RFKO method is considered to be a good method to obtain a stable and more-or-less homogenous beam spill. To benefit the spot scanning method, the extraction energy can be as many as about 200 between 60 MeV and 230 MeV. A new method—the emittance balancing technique of using a solenoid or a quadrupole rotator is proposed to solve the problem of unequal emittance in the two transverse planes with a beam slowly extracted from a synchrotron. The facility has been designed to keep the potential to be upgraded to include the carbon therapy in the future.

Eddy current septum magnets for injection and extraction at SSRF
OUYANG Lian-Hua, GU Ming, LIU Bo, CHEN Rong
2010, 34(3): 389-393. doi: 10.1088/1674-1137/34/3/016

There are 6 in-vacuum eddy current septum magnets used for booster injection, extraction, and storage ring injection in SSRF. Special attention was paid to coils and their support designs because of the shock force they bear in the magnetic fields and the high heat which is hard to be dissipated in vacuum environment. For the storage ring magnets, good transverse homogeneity in the gap was achieved by careful design, precise machining and accurate assembly; and an extremely low leakage field on the stored beam is another key feature thanks to the high permeability Mu metal. Magnetic field measurement was conducted with both a point coil and a long integral coil, and the results agree well with the OPERA-2d/3d simulations. An inner tube is added to keep the continuity of impedance for the circulating beam with two RF finger flanges at each end. There is no vacuum separation between the inner tube and the magnet chamber. Sputter ion pumps integrated with NEG are used to acquire the UHV for the chamber.

Physical design of scanning gantry for proton therapy facility
JIAO Yi, GUAN Xia-Ling, SATOGATA Todd, FANG Shou-Xian, WEI Jie, TANG Jing-Yu, CHEN Yuan, QIU Jing, SHU Hang
2010, 34(3): 394-397. doi: 10.1088/1674-1137/34/3/017

A proton therapy facility based on a linac injector and a slow cycling synchrotron is proposed. To achieve effective treatment of cancer, a scanning gantry is required. The flexible transmission of beam and high beam position accuracy are the most basic requirements for a gantry. The designed gantry optics and scanning system are presented. Great efforts are put into studying the sensitivity of the beam position in the isocenter to the element misalignments. It shows that quadrupole shift makes the largest contribution and special attention should be paid to it.

Study on shunt impedance and voltage distribution of 4-rod RFQ cavity
ZHANG Zhou-Li, ZHAO Hong-Wei, XU Zhe, ZHANG Sheng-Hu, ZHANG Cong, SUN Lie-Peng, MEI Li-Rong, SHEN Xiao-Kang
2010, 34(3): 398-401. doi: 10.1088/1674-1137/34/3/018

A high current RFQ (radio frequency quadrupole) is being studied at the Institute of Modern Physics, CAS for the direct plasma injection scheme. Shunt impedance is an important parameter when designing a 4-rod RFQ cavity, it reflects the RF efficiency of the cavity, and has a direct influence on the cost of the structure. Voltage distribution of a RFQ cavity has an effect on beam transmission, and particles would be lost if the actual voltage distribution is not as what it should be. The influence of cell length, stem thickness and height on shunt impedance and voltage distribution have been studied, in particular the effect of projecting electrodes has been investigated in detail.

200 MW S-band traveling wave resonant ring development at IHEP
ZHOU Zu-Sheng, CHI Yun-Long, GU Meng-Ping, PEI Guo-Xi
2010, 34(3): 402-404. doi: 10.1088/1674-1137/34/3/019

The resonant-ring is a traveling wave circuit, which is used to produce high peak power with comparatively smaller stored energy. The application to be
considered is its use as a high power simulator mainly for testing the klystron ceramic output window, as well as for high power microwave transmission devices. This paper describes the principle of a resonant ring and introduces the structure and property of the newly constructed traveling wave resonant ring at IHEP. Our goal is to produce a 200 MW class resonant ring at 2.856 GHz with a pulse length of 2 μs and repetition rate of 25 Hz. The installation, commissioning and testing of the ring have been completed and a peak power of 200 MW at 3 μs has been achieved. The conditioning results show that all the parameters of the resonant ring reach the design goals.

Simulation and experiments for the Qext of a cavity beam position monitor
LI Xiang, ZHENG Shu-Xin
2010, 34(3): 405-408. doi: 10.1088/1674-1137/34/3/020

The external Q (Qext) of the dipole mode is a key parameter of the Cavity Beam Position Monitor (CBPM). It determines the amplitude and length of the dipole mode signal. In this paper, Qext of a CBPM whose waveguides were open to the air was simulated and measured, and the results agreed with each other. Then four waveguide-to-coaxial cable adpaters were adjusted and assembled to the CBPM, and Qext remained unchanged. This progress provides a reliable method to evaluate Qext in the physics design without simulating the structurally complex adapters.

Stochastic motion of the untrapped particle in electrostatic mode
ZHU Xiong-Wei
2010, 34(3): 409-411. doi: 10.1088/1674-1137/34/3/021

The stochastic energy diffusion of the untrapped particle in the electrostatic mode is investigated analytically. We find that the equilibrium electrostatic field of periodical structure plays the same role as the usual focusing magnetic field to lead the test particle to stochastic motion. The resonance overlapping criterion for the random state is given, and also the Fokker-Planck-Kolmogorov approach to diffusion is considered for our system.

Synchrotron radiation,applications of nuclear techniquees,etc
Measurement of spatial resolution of the micro-CT system
RONG Jun-Yan, FU Guo-Tao, WEI Cun-Feng, SUN Cui-Li, WEI Long
2010, 34(3): 412-416. doi: 10.1088/1674-1137/34/3/022

The performance test is an important and necessary work for the micro-CT (computed tomography) system. The focal spot size of the micro focus X-ray tube is measured. The method of measuring the spatial resolution of micro-CT is introduced. A line-pair resolution of 28.2 lp/mm at the 10% modulation transfer function (MTF) level can be achieved with 14.7 μm spot size, 12.3 μm voxel size and a 25 mm field of view. In addition, a tungsten wire with the diameter of 5 μm can be detected by the system.

Study of the circumstance influence on the elemental distribution in ancient animal bone using μ-XRF
YAN Ling-Tong, FENG Song-Lin, FENG Xiang-Qian, XIE Guo-Xi, LI Li, XU Wei
2010, 34(3): 417-420. doi: 10.1088/1674-1137/34/3/023

Elemental analysis of archaeological bone plays an important role in the study of the dietary habits of ancient animals. The elemental characteristic of diagenetic skeletons depends on the surrounding circumstance. The study of environmental influence on the elemental concentration of ancient bone is significant. In this paper, the diagenetic influence on archaeological skeletons is analyzed by microbeam X-ray fluorescence (μ-XRF). The results show that the enamel is an excellent barrier to the diagenesis and the element Sr in bone isn't susceptible to contamination from the buried environment.