2010 Vol. 34, No. 1

Particle and field theory
Casas-Ibarra parametrization and leptogenesis
XING Zhi-Zhong
2010, 34(1): 1-6. doi: 10.1088/1674-1137/34/1/001

The Casas-Ibarra parametrization is a description of the Dirac neutrino mass matrix MD in terms of the neutrino mixing matrix V, an orthogonal matrix O and the diagonal mass matrices of light and heavy Majorana neutrinos in the type-I seesaw mechanism. Because MD MD is apparently independent of V but dependent on O in this parametrization, a number of authors have claimed that unflavored leptogenesis has nothing to do with CP violation at low energies. Here we question this logic by clarifying the physical meaning of O. We establish a clear relationship between O and the observable quantities, and find that O does depend on V. We show that both unflavored leptogenesis and flavored leptogenesis have no direct connection with low-energy CP violation.

Analysis of the coupling constants ga0ηπ0 and ga0η′π0 with light-cone QCD sum rules
WANG Zhi-Gang
2010, 34(1): 7-15. doi: 10.1088/1674-1137/34/1/002

In this article, we take the point of view that the light scalar meson a0(980) is a conventional qq state, and calculate the coupling constants ga0ηπ0 and ga0η′π0 with the light-cone QCD sum rules. The central value of the coupling constant ga0ηπ0 is consistent with that extracted from the radiative decay φ(1020)→a0(980)γ→ηπ0γ. The central value and lower bound of the decay width Γa0→ηπ0=127+84-48 MeV are compatible with the experimental data of the total decay width Γa0(980)=(50-100) MeV from the Particle Data Group with a very model dependent estimation (the decay width can be much larger), while the upper bound is too large. We give a possible explanation for the discrepancy between the theoretical calculation and experimental data.

D and Ds in mass loaded flux tube
SHAN Hong-Yun, ZHANG Ai-Lin
2010, 34(1): 16-21. doi: 10.1088/1674-1137/34/1/003

Heavy-light hadrons are studied in a mass loaded flux tube model. The study indicates that the dynamics of mesons and baryons containing a c quark is described well by the mass loaded flux tube. The hypothesis of good diquark-antiquark degeneracy is found reasonable in heavy-light quark systems. The spectrum of charmed (D) and charmed strange (Ds) mesons is systematically computed. D and Ds in 1D multiplets are predicted to have lower masses in comparison with other theoretical predictions. The predicted masses of the 1(13D1) and the 3(13D3) Ds agree well with those of recently observed Ds1(2700)± and DsJ(2860), respectively.

J/ψ-N center of mass energy dependence of nuclear absorption effect on J/ψ production
WANG Hong-Min, HOU Zhao-Yu, LIU Jia-Fu, SUN Xian-Jing
2010, 34(1): 22-27. doi: 10.1088/1674-1137/34/1/004

In this paper, the J/ψ nuclear absorption effect is studied at RHIC and LHC energies with the EKS98 shadowing parameterizations. By assuming that the J/ψ absorption cross section, σabs, increases with the charmonium-nucleon (J/ψ-N) center of mass energy, √sJ/ψ N, it is found that σabs should depend on xF (or y) at a certain center of mass energy per nucleon pair, √s, especially at LHC energies. The theoretical results with the xF (or y)-dependence of the absorption effect are in good agreement with the experiment data from PHENIX in d-Au collisions and the predicted results will be examined by the forthcoming experimental data from LHC in d-Pb collisions. Finally, we also present baseline calculations of cold nuclear matter effects on J/ψ production in nucleus-nucleus (A-A) collisions and find that the xF (or y)-dependence of absorption effect is very small at both RHIC and LHC energies in A-A collisions.

particle and nuclear astrophysics and cosmology
Towards a gravitation theory in Berwald-Finsler space
2010, 34(1): 28-34. doi: 10.1088/1674-1137/34/1/005

Finsler geometry is a natural and fundamental generalization of Riemann geometry. The Finsler structure depends on both coordinates and velocities. It is defined as a function on tangent bundle of a manifold. We use the Bianchi identities satisfied by the Chern curvature to set up a gravitation theory in Berwald-Finsler space. The geometric part of the gravitational field equation is
nonsymmetric in general. This indicates that the local Lorentz invariance is violated.

Nuclear and ion Physics
Energy calibration of tagged photons by the d(γ, πpp) reaction
HAN Yun-Cheng, Nobuyuki Chiga, Yu Fujii, Kenta Futatsukawa, Osamu Hashimoto, Kentaro Hirose, Takatsugu Ishikawa, Hiroki Kanda, Masashi Kaneta, Daisuke Kawama, Yue Ma, Kazushige Maeda, Tomofumi Maruta, Nayuta Maruyama, Akihiko Matsumura, Youhei Miyagi, Koji Miwa, Satoshi N, Hajime Shimizu, Koutarou Shirotori, Koutaku Suzuki, Tadaaki Tamae, Hirokazu Tamura, Kyo Tsukada, WANG Tie-Shan, Hirohito Yamazaki
2010, 34(1): 35-38. doi: 10.1088/1674-1137/34/1/006

The energy of tagged photons, which were provided from the internal photon tagging system of the Laboratory of Nuclear Science, Tohoku University, has been calibrated using the d(γ, πpp) reaction. Charged pions and protons in the final state were detected with the Neutral Kaon Spectrometer (NKS2). Photon energies were obtained from the reaction of d(γ, πpp). The derived photon energy was consistent with the design of the tagger system and the previous measurement using electron-positron pair production. The consistency demonstrates the performance of NKS2 and the capability of the photon energy calibration using d(γ, πpp).

Particle-number-conserving analysis of multiquasiparticle bands in 177Lu
ZHANG Zhen-Hua, QI Shou-Tao, SUN Bao-Xi, LEI Yi-An, ZENG Jin-Yan
2010, 34(1): 39-44. doi: 10.1088/1674-1137/34/1/007

The experimental one-, three-, and five-quasiparticle bands in 177Lu are analyzed by the particle-number conserving (PNC) method for treating the cranked shell model with pairing interaction, in which the blocking effects are taken into account exactly. The experimental moments of inertia are reproduced very well by PNC calculations with us free parameter.

Surveying post-saddle nuclear dissipation with protons and α particles as probes
YE Wei
2010, 34(1): 45-48. doi: 10.1088/1674-1137/34/1/008

Using a Langevin model, we calculate post-saddle proton and α-particle multiplicities as a function of the post-saddle dissipation strength (β) for the heavy systems 234Cf, 240Cf, 246Cf and 240U. We find that, with increasing isospin of the system, the sensitivity of post-saddle light charged-particle multiplicities to β decreases considerably and, moreover, for 240U the charged-particle multiplicities are no longer sensitive to β. These results suggest that in order to determine the post-saddle friction strength more accurately by measuring the multiplicities of pre-scission protons and α particles, it is best to populate those heavy compound systems with low isospin.

Multi-modal analysis for low energy neutron-induced fission of 235U
ZHENG Na, FAN Tie-Shuan, DING Yi, ZHONG Chun-Lai, LI Xiang-Qing, CHEN Jin-Xiang
2010, 34(1): 49-55. doi: 10.1088/1674-1137/34/1/009

Low energy neutron induced fission of 235U is studied in the framework of the multi-modal fission model. The fission fragment properties, such as the yields, the average total kinetic energy distribution and the average neutron separation energy, are investigated for incident neutron energies from thermal to 6.0 MeV. The multi-modal fission approach is also used to evaluate the prompt fission neutron multiplicity and spectra for the neutron-induced fission of 235U with an improved version of the Los Alamos model for incident neutrons below the (n, nf) threshold. The three most dominant fission modes are taken into account. The model parameters are determined on the basis of experimental data. The calculated results are in good agreement with the experimental data.

Nuclear structure around 80Zr
ZOU Wen-Hua, TIAN Yuan, SHEN Shui-Fa, GU Jian-Zhong, PENG Bang-Bao, ZHANG Di-Da, MA Zhong-Yu
2010, 34(1): 56-61. doi: 10.1088/1674-1137/34/1/010

Recent years have witnessed intense activity concerning the study of nuclei with equal numbers of neutrons and protons (N=Z). Exotic properties have been exhibited in the N=Z nuclei, especially in those with atomic masses around 80. In the present paper, the projected shell model (PSM) together with a relativistic Hartree-Bogoliubov (RHB) theory is used to study the nuclear structure near the N=Z line in the mass A≈80 region. For three Zr isotopes 80,82,84Zr, the projected potential energy surfaces and ground state bands are calculated. It is shown that shape coexistence occurs in all of these nuclei. Moreover, we find that the residual neutron-proton interaction strongly affects the ground state band of 80Zr; however, it slightly modifies those of 82Zr and 84Zr.

Space-momentum correlations in 8 AGeV Au+Au collisions
WU Feng-Juan, SHAN Lian-Qiang, FENG Qi-Chun, HUO Lei
2010, 34(1): 62-65. doi: 10.1088/1674-1137/34/1/011

Within the RQMD model, space-momentum correlations, i.e. the correlations between final momentum anisotropy and initial eccentricity, are studied for 8 AGeV Au+Au events classified according to the multi-particle azimuthal correlations. The results show that the final elliptic flow fluctuations depend on the initial collision geometry. There are clear space-momentum correlations for
nucleons during the whole dynamical evolution of the collisions.

Detection Technology and Methods
A study of the pointed observation methods and sensitivity of HXMT
JIN Jing, CHEN Yong, ZHANG Shuang-Nan, ZHANG Shu, LI Xin-Qiao, LI Gang
2010, 34(1): 66-71. doi: 10.1088/1674-1137/34/1/012

The Hard X-ray Modulation Telescope (HXMT) is an X-ray astronomy satellite consisting of three slat-collimated instruments, the High Energy X-ray Instrument (HE), the Medium Energy X-ray Instrument (ME), and the Low Energy X-ray Instrument (LE). HXMT will carry out an all sky survey and make pointed observations in the 1-250 keV energy band. In order to get the source and background fluxes simultaneously in the pointed observations, two methods, i.e., the combined field of view (FOV) method and the off-axis pointing method
are proposed in this paper. Comprehensive analyses of the sensitivities of the three instruments by using these two methods are presented, respectively. It is found that the off-axis pointing method has a higher sensitivity for HE and ME but a lower sensitivity for LE. Since the axes of the three instruments are aligned along the same direction, the off-axis pointing method is recommended as the main method in the pointed observation for HXMT; the combined FOV method can be used when LE is the most relevant instrument in order to satisfy the scientific objective of the observation.

Absolute photon energy calibration for the BESⅢ EMC
BIAN Jian-Ming, HE Kang-Lin, LI Wei-Guo, HU Tao, FU Cheng-Dong, HUANG Bin, LIU Ying, NING Fei-Peng, SONG Wen-Bo, SUN Sheng-Sen, XU Min, YAN Jie, YAN Liang
2010, 34(1): 72-77. doi: 10.1088/1674-1137/34/1/013
The absolute energy calibration with photons from π0's for the BESⅢ EMC is discussed. Using 3 million hadronic events, the preliminary results are
presented. Precision of about 1% in the photon energy measurement is
obtained from crossing check using photons in ψ(2S)→γχc1,2(1P).
An X-ray imaging device based on a GEM detector with delay-line readout
ZHOU Yi, LI Cheng, SUN Yong-Jie, SHAO Ming
2010, 34(1): 78-82. doi: 10.1088/1674-1137/34/1/014

An X-ray imaging device based on a triple-GEM (Gas Electron Multiplier) detector, a fast delay-line circuit with 700 MHz cut-off frequency and two dimensional readout strips with 150 μm width on the top and 250 μm width on the bottom, is designed and tested. The localization information is derived from the propagation time of the induced signals on the readout strips. This device has a good spatial resolution of 150 μm and works stably at an intensity of 105 Hz/mm2 with 8~keV X-rays.

Experimental study on the performance of a single-THGEM gas detector
AN Zheng-Hua, WANG Zhi-Gang, CAI Xiao, DONG Ming-Yi, FANG Jian, HU Tao, NING Fei-Peng, SUN Li-Jun, SUN Xi-Lei, WANG Xiao-Dong, XUE Zhen, YU Bo-Xiang, ZHANG Ai-Wu, ZHOU Li, ZHENG Yang-Heng
2010, 34(1): 83-87. doi: 10.1088/1674-1137/34/1/015
A kind of thick GEM-like gaseous electron multiplier (THGEM), which is mechanically an expansion of the GEM with its various dimensions being enlarged, is studied. The leak current of THGEM plates is measured. The effective gain and energy resolution of a single THGEM are studied with a source of 55Fe, and the effective gain of the single THGEM versus the electric field strength in the induction region is investigated. The results show that the leak current of THGEM plates is less than 200 pA. In an atmospheric-pressure standard gas mixture, 8×103 effective gain and about 32% energy resolution can be reached for the single-THGEM detector.
An MRPC for fast neutron detection
WANG Yi, CHENG Jian-Ping, LI Yuan-Jing, LUO Ming, ZHANG Guo-Guang
2010, 34(1): 88-91. doi: 10.1088/1674-1137/34/1/016

The possibility to detect fast neutrons with a multi-gap resistive plate chamber (MRPC) has been investigated. To detect fast neutrons, a thin polyethylene layer is coated on the surface of electrode glass as a fast neutron converter. The MRPC detects the charged particles generated by neutrons via the (n,p) reaction on hydrogen. A prototype detector has been developed and tested on fast neutron sources in order to evaluate its performance: good agreement between experimental results and simulation has been achieved. A detailed
description of the detector and the experimental test results are presented.

Primary vertex reconstruction based on the Kalman filter technique at BESⅢ
XU Min, HE Kang-Lin, ZHANG Zi-Ping, WANG Yi-Fang, BIAN Jian-Ming, FU Cheng-Dong, HUANG Bin, JI Xiao-Bin, SUN Sheng-Sen, YAN Liang, ZHANG Jian-Yong
2010, 34(1): 92-98. doi: 10.1088/1674-1137/34/1/017
Primary vertex reconstruction is crucial to estimate the beam profile in collision experiments. We study the principle of an iterative process, called the Kalman filter method, and apply it to primary vertex reconstruction at BESⅢ. A Newton procedure to find the zero point of the distance function's gradient is used for primary vertex finding in 3-dimensional space. Results are obtained based on raw data at BESⅢ.
HOM study and parameter calculation of the TESLA cavity model
ZENG Ri-Hua, SCHUH Marcel, GERIGK Frank, WEGNER Rolf, PAN Wei-Min, WANG Guang-Wei, LIU Rong
2010, 34(1): 99-102. doi: 10.1088/1674-1137/34/1/018

The Superconducting Proton Linac (SPL) is the project for a superconducting, high current H- accelerator at CERN. To find dangerous higher order modes (HOMs) in the SPL superconducting cavities, simulation and analysis for the cavity model using simulation tools are necessary. The existing TESLA 9-cell cavity geometry data have been used for the initial construction of the models in HFSS. Monopole, dipole and quadrupole modes have been obtained by applying different symmetry boundaries on various cavity models. In calculation, scripting language in HFSS was used to create scripts to automatically calculate the parameters of modes in these cavity models (these scripts are also available in other cavities with different cell numbers and geometric structures). The results
calculated automatically are then compared with the values given in the TESLA
paper. The optimized cavity model with the minimum error will be taken as the base for further simulation of the SPL cavities.

Design and construction progress of BRIF
ZHANG Tian-Jue, GUAN Xia-Ling, CUI Bao-Qun
2010, 34(1): 103-111. doi: 10.1088/1674-1137/34/1/019

A new RIB project, the Beijing Radioactive Ion-beam Facility (BRIF), has been running at CIAE since 2004. In this project, a 100 MeV H-cyclotron, CYCIAE-100, is selected as the driving accelerator providing a 75-100 MeV, 200-500 μA proton beam. An ISOL system employs two stage separators to reach the mass resolution of 20000. Its RIB beam will be injected into the existing Tandem and a superconducting booster installed down stream of the Tandem will increase the energy by 2 MeV/q. The progress of BRIF, giving special emphasis to CYCIAE-100, will be introduced in this paper.

Towards one machine, two purposes: using a common SC linac for XFEL and ERL simultaneously
CHEN Sen-Yu, WANG Shu-Hong, ZHU Xiong-Wei
2010, 34(1): 112-114. doi: 10.1088/1674-1137/34/1/020

The linac based XFEL and ERL are advanced (or, say, 4th generation) light sources, with different electron beam parameters and different advantages. However, the linac used for XFEL and ERL should provide very advanced beams with high energy, high peak and/or average current, very low emittance and low energy spread, thus making the linac very complicated and expensive. To share the XFEL and ERL advantages and save the construction-operation budget, a proposal of using a common superconducting electron linac for hard X-ray XFEL and ERL is described in this paper. The interactions between the XFEL and ERL beams via the accelerating structure are studied and the result is positive.

Three dimensional study of harmonic operation at the Shanghai deep ultraviolet free electron laser
DENG Hai-Xiao, BEI Hua, DAI Zhi-Min
2010, 34(1): 115-120. doi: 10.1088/1674-1137/34/1/021

With the right choice of parameters in the free electron laser (FEL) scheme, the undulator can be primarily operated at high order harmonic modes and the harmonic radiation is expected to be significantly enhanced. Recently, the possibility of proof-of-principle harmonic operation experiments on the basis of the Shanghai deep ultraviolet (SDUV) FEL test facility has been studied. In this paper, the principle of harmonic operation, three dimensional numerical approaches, and detailed performances of proposed harmonic operation at SDUV FEL are presented.

Proposal for muon and white neutron sources at CSNS
TANG Jing-Yu, FU Shi-Nian, JING Han-Tao, TANG Hong-Qing, WEI Jie, XIA Hai-Hong
2010, 34(1): 121-125. doi: 10.1088/1674-1137/34/1/022

The China Spallation Neutron Source (CSNS) is a large scientific facility with the main purpose of serving multidisciplinary research on material characterization using neutron scattering techniques. The accelerator system is to provide a proton beam of 120 kW with a repetition rate of 25 Hz initially (CSNS-Ⅰ), progressively upgradeable to 240 kW (CSNS-Ⅱ) and 500 kW (CSNS-Ⅱ'). In addition to serving as a driving source for the spallation target, the proton beam can be exploited for serving additional functions both in fundamental and applied research. The expanded scientific application based on pulsed muons and fast neutrons is especially attractive in the overall consideration of CSNS upgrade options. A second target station that houses a muon-generating target and a fast-neutron-generating target in tandem, intercepting and removing a small part of the proton beam for the spallation target, is proposed. The muon and white neutron sources are operated principally in parasitic mode, leaving the main part of the beam directed to the spallation target. However, it is also possible to deliver the proton beam to the second target station in a dedicated mode for some special applications. Within the dual target configuration, the thin muon target placed upstream of the fast-neutron target will consume only
about 5% of the beam traversed; the majority of the beam is used for
fast-neutron production. A proton beam with a beam power of about 60 kW,
an energy of 1.6 GeV and a repetition rate of 12.5 Hz will make the muon
source and the white neutron source very attractive to multidisciplinary

Monitoring the energy variation of an electron linac using a Cerenkov detector
LI Shu-Wei, WANG Yi, LI Jin, LI Yuan-Jing, KANG Ke-Jun, LIN De-Xu, ZHANG Qing-Jun
2010, 34(1): 126-130. doi: 10.1088/1674-1137/34/1/023

A new method to monitor the energy variation of a multi-energy electron linac by combining a Cerenkov detector and a CsI(Tl) detector is reported. The signals in the Cerenkov detector show an appreciable but different dependence on the energy of the electron linac from the traditional CsI(Tl) detector due to the particular response of the former to charged electrons with high velocity above threshold. The method is more convenient than the HVL (half-value layer) method which is commonly employed to calibrate the energy of an electron linac for real time monitoring. The preliminary validity~of the method is verified in a dual-energy electron linac with 6 MeV and 3 MeV gears. Moreover, the method combining the Cerenkov detector and the CsI(Tl) detector is applicable to probe the X-ray spectrum hardened by the inspected material and may serve as a novel tool for material discrimination with effective atomic number in radiation imaging.

An integrating current transformer for fast extraction from the HIRFL-CSR main ring
WU Jun-Xia, ZHENG Jian-Hua, ZHAO Tie-Cheng, MAO Rui-Shi, YIN Yan, YUAN You-Jin, YANG Jian-Cheng
2010, 34(1): 131-133. doi: 10.1088/1674-1137/34/1/024

For any experiment that uses the beam of an accelerator, monitoring the beam intensity is always an important concern. It is particularly useful if one can continuously measure the beam current without disturbing the beam. We report here on test experiments for an Integrating Current Transformer (ICT) used to measure fast extraction beams from the HIRFL-CSR main ring (CSRm). The laboratory tests and beam intensity measurement results are presented in this paper. The influence of the kicker noise is also analyzed.

Lie algebraic analysis and simulation of high-current pulsed beam transport in a solenoidal lens
ZHANG Zhuo, YANG Guo-Jun
2010, 34(1): 134-137. doi: 10.1088/1674-1137/34/1/025
Recent calculations of the transport of a high-current beam in a solenoidal lens have made progress to the second order with the Lie algebraic method. A review of the theory and our simulation to realize it will be described. Then we will present the results of simulation. A brief discussion on the space charge effect's contribution to the transportation will also be made.
Synchrotron radiation,applications of nuclear techniquees,etc
Bunch length measurement using a traveling wave RF deflector
ZHANG Jing-Ru, DAI Jian-Ping, GU Qiang, PEI Guo-Xi, ZHAO Ming-Hua, ZHONG Shao-Peng, WANG Xing-Tao, CHEN Yong-Zhong, HOU Mi
2010, 34(1): 138-142. doi: 10.1088/1674-1137/34/1/026

RF deflectors can be used for bunch length measurement with high resolution. This paper describes a completed S-band traveling wave RF deflector and the bunch length measurement of the electron beam produced by the photocathode RF gun of the Shanghai DUV-FEL facility. This is the first time that such a transverse RF deflector has been developed and used to measure the bunch length of picosecond order in China. The deflector's VSWR is 1.06, the whole attenuation 0.5 dB, and the bandwidth 4.77 MHz for VSWR less than 1.1. With a laser pulse width of 8.5 ps, beam energy of 4.2 MeV, and bunch charge of 0.64 nC, the bunch lengths for different RF input power into the deflector were measured, and an averaged rms bunch length of 5.25 ps was obtained. A YAG crystal is used as a screen downstream of the deflector, with the calibrated value of 1 pix=136 μm.

Determination of the number of atoms of the long-lived nuclide 126Sn by γ-ray spectrometry
SHEN Hong-Tao, JIANG Shan, HE Ming, DONG Ke-Jun, LI Chao-Li, WANG Xiang-Gao, HE Guo-Zhu, GONG Jie, LU Li-Yan, LI Shi-Zhuo, ZHANG Da-Wei, SHI Guo-Zhu, HUANG Chun-Tang, WU Shao-Lei, WU Shao-Yong
2010, 34(1): 143-147. doi: 10.1088/1674-1137/34/1/027

By using HPGe γ-ray spectrometry, the activity of the long-lived fission product 126Sn in a SnOB2 sample was measured. The number of 126Sn atoms and the ratio of 126Sn to Sn were calculated based on the half-life value of 2.35×105a and the chemical stoichiometry. The result of the ratio of 126Sn to Sn, (1.033±0.037)×10-8, is consistent with the results measured by the accelerator mass spectrometry (AMS) within uncertainty limits, which confirms our procedures in the measurement of 126Sn by AMS and lays a foundation for the AMS measurement of 126Sn at much lower levels.

Comparison study of the charge density distribution induced by heavy ions and pulsed lasers in silicon
TIAN Kai, CAO Zhou, XUE Yu-Xiong, YANG Shi-Yu
2010, 34(1): 148-151. doi: 10.1088/1674-1137/34/1/028

Heavy ions and pulsed lasers are important means to simulate the ionization damage effects on semiconductor materials. The analytic solution of high-energy heavy ion energy loss in silicon has been obtained using the Bethe-Bloch formula and the Kobetich-Katz theory, and some ionization damage parameters of Fe ions in silicon, such as the track structure and ionized charge density distribution, have been calculated and analyzed according to the theoretical calculation results. Using the Gaussian function and Beer's law, the parameters of the track structure and charge density distribution induced by a pulsed laser in silicon have also been calculated and compared with those of Fe ions in silicon, which provides a theoretical basis for ionization damage effect modeling.

Preliminary simulation studies on a cylindrical PEM scanner using GATE
YAN Qiang, GAO Juan, SHAN Bao-Ci, WEI Long
2010, 34(1): 152-156. doi: 10.1088/1674-1137/34/1/029

In this paper, we investigate the performance of a cylindrical positron emission mammography (PEM) by simulation, in order to estimate its feasibility before implementation. A well-developed simulation package, Geant4 Application for Tomographic Emission (GATE), is used to simulate the scanner geometry and physical processes. The simulated PEM scanner is composed of 64 blocks axially arranged in 4 rings with an axial field-of-view (AFOV) of 12.8 cm and 16.6 cm in diameter. For each block, there is a 16×16 array of 2 mm×2 mm×15 mm lutetium yttrium oxyorthosilicate (LYSO) crystals. In the simulated measurements, the spatial resolution is at the center of the FOV of 1.73±0.07 mm (radial) and 1.81±0.08 mm (tangential), but of 4.83±0.09 mm (radial) and 4.37±0.07 mm (tangential) while 5 cm off the center. The central point source sensitivity (ACS) is 4.04% (1.50 Mcps/mCi) at an energy window of 350-650 keV. Moreover, the capillary and cylindrical sources are simulated coupled to breast phantoms for the scatter fraction (SF) and Noise Equivalent Count Rate (NECR) test. For a breast phantom with a 350-650 keV energy window, SF may reach the highest 32.95%, while NECR is degraded down to the lowest 255.71 kcps/mCi. Finally, we model a breast phantom embedded with two spheres of different activities. The reconstructed image gives good results despite a bit of difference in image contrast. Further, the image quality will be improved by scatter and random correction. All these test results indicate the feasibility of this PEM system for breast cancer detection.