[en] The cavity mode method is a new method for computing the dispersion curves and fields of accelerating structures. The method assumes that the field of interest is expanded with open and short modes. These modes are constructed on the basis of the resonant fields in a unit cell. With the wave equation and the Floquet boundary conditions, the method is mathematically simplified into a general eigenvalue problem to calculate the dispersion curve and fields for any phase shift in the structures. This method has been used in analyzing the higher-order modes in the periodic structures. In further study, it is also expected to be useful for analyzing non-periodic structures in the next generation linear collider

[en] The Vlasov equation is solved by expansion in terms of generalized Laguerre polynomials. Some studies on microwave instability are done based on the code and some results are obtained

[en] Background: Seismic test analysis of a cabinet in 18-5 critical device building is required for safety inspection of zero power reactor, however, the floor response spectra at the height of 3.5 m where the cabinet is located are lacking. Purpose: For seismic test analysis of the cabinet in 18-5 critical device building, dynamic analysis is performed for the building, with the purpose to obtain the floor response spectra at the height of 3.5 m where the cabinet is located. Methods: The displacement time history and acceleration time history on the given height floor are calculated by using transient dynamic time history method with the software ANSYS under the load of foundation displacement time history, then acceleration response spectrum on the floor that the cabinet locates is calculated with the corresponding acceleration time history obtained on the cabinet floor. Results: The design floor response spectra under load OBE and SSE at the height of 3.5 m are offered with damping ratios of 2%, 4%, 5% and 7%, respectively. Conclusions: The design floor response spectra are credible and have been adopted by test analysis of the cabinet. (authors)

[en] In this paper, we present the analysis of the spectral distributions of the scattered photons within a certain acceptance angle in Thomson scattering, in which the beam divergence, energy spread and spatial distribution are all considered. The analytical results are compared with the simulation results, and good agreement between the two approaches is obtained. (authors)

[en] Objective: To evaluate the value of radionuclide ⁹⁹Tc^m-MIBI myocardial scanning for the diagnosis of apical hypertrophic cardiomyopathy (AHCM). Methods: Thirty-two cases with typical ECG of AHCM were studied by ultrasonic cardiography (UCG), radionuclide ⁹⁹Tc^m-MIBI myocardial scanning, coronary angiography and left ventriculography. Results: Twenty-nine patients were diagnosed with AHCM. The diagnostic sensitivity of SPECT vs UCG in AHCM was 89.7% vs 93.1%. The specificity was 100% for both. There was no significant difference in diagnosis of AHCM between UCG and ECT. Conclusion: SPECT is an effective method for diagnosing AHCM

[en] A new CW electron accelerator with a single compact RF cavity, the Rhodotron, has been applied widely in many fields of industrial irradiation. The paper focuses on dynamics characteristics of the Rhodotron. The longitudinal and transverse dynamics simulations have been performed with the Parmela code. In this paper, synchronous condition of beam acceleration is deduced and the process of longitudinal phase capture is also studied. The problem that bulks overlap each other in the center of the RF cavity under the CW mode is solved by adjusting the parameters of bending magnets. The process that the major traverse focusing is achieved using the bending magnets is analyzed carefully. It is generalized how the space charge effect and the variation of initial parameters impact on transverse beam stability. The distribution of beam losing power is calculated for the radiation protection of this machine. The simulation results agree with the operational parameters of the Rhodotron's prototype, which confirm the research method's feasibility

[en] A bunch charge monitor system has been designed for the photocathode RF gun of Accelerator Laboratory, Tsinghua University. Integrating current transformer is the most important part of the system, and parts of the system after integrating current transformer consist of a preamplifier, an integrator, an AD converter and a data collection module. The system does not destroy the beam, and it can monitor the bunch charge in the high-radiation environment around accelerator. The results of some off-line tests show that the system is feasible. (authors)

[en] Theoretical analysis of thermal emittance of photoinjectors is presented in this paper. Thermal emittance of metal photo-cathode mainly consists of two parts. One is due to thermal emittance of ideal flat metal cathode, and the other is due to surface roughness. To analyze the former part of the thermal emittance, a new model for the electron distribution emitted from the photocathode is presented, and a formula of the thermal emittance of an idea flat cathode is derived according to this model. As to the influence on the thermal emittance from the roughness of the cathode, authors also give the analytical results with a simplified model. Surface profile measurement of Copper and Magnesium after diamond cutting shows normalized RMS thermal emittance due to surface roughness is about 0.4 mm·mrad. Thermal emittance expressions analytical given in this paper can explain some of the existing experimental results very well. (author)

[en] When the bunch goes through a Chicane, the energy will be redistributed within the bunch due to CSR (coherent synchrotron radiation), which would cause nonlinearity. Present theory states that this nonlinearity would add a huge amount to emittance growth. Based on simulation results, this paper would point out that the theory is only valid under an ideal condition that the bunch initially has no nonlinearity and under some given parameters there could be a cancellation between the nonlinearity caused by CSR and the initial nonlinearity. So under these circumstances authors can expect CSR to improve the beam quality. This paper provides a brief information about CSR and a full estimation of effects of CSR on beam qualities

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