Vol.23,

With the potential application of Energy Recovery Linac (ERL), the superconducting (SC) cavities were developed to deliver much higher current than before. Nowadays, the current of the international SC accelerator designed has already exceeded 100 mA. This paper presents the design of a new 500 MHz 5-cell SC cavity (SINAP 5-cell cavity), in which the parameters r/Q= 515.5 Ω of the fundamental mode and the geometry factor G=275.8 are under an acceptable Radio Frequency (RF) ﬁeld level (B_peak/E_acc=4.31 mT/MV/m and E_peak/E_acc=2.48). This design employs a larger beam pipe to propagate the Higher Order Modes (HOMs) out of the cavity and increases the damping efficiently for the dangerous HOMs. By simulation technique, it has been found that almost all the dangerous HOMs (including TE₁₁₁, TM₁₁₀, and TM₀₁₁) can be propagated into the beam pipe and are absorbed by ferrite absorbers, when the beam pile is enlarged. Finally, the loss factor for the new 5-cell cavity is also calculated.

433

A data processing program has been applied for the new beam position monitor (BPM) system of the storage ring at Hefei Light Source (HLS). The new BPM system in the upgrade project will be equipped with Libera Brilliance BPM processors to replace the old Bergoz MX-BPM processors. The embedded Linux system on Libera has completed some important work, including instrument status check, data acquisition, position calculation, EPICS IOC data release, and so on. A new EPICS record type has been developed to recalculate the beam position with log-ratio method. The property of the new position data was analyzed in the time and frequency domain. The results show that the rms value of beam position measurement resolution can be up to submicron. Preliminary studies have been carried out on the measurement of the tune and the beam lifetime with this new BPM system.

375

The control system of Shanghai Synchrotron Radiation Facility (SSRF) is a large-scale distributed real-time control system. It involves many types and large amounts of real-time data access during the operating. Database system has wide application prospects in the large-scale accelerator control system. It is the future development direction of the accelerator control system, to replace the differently dedicated data structures with the mature standardized database system. This article discusses the application feasibility of database system in accelerators based on the database interface technology, real-time data access testing, and system optimization research and to establish the foundation of the wide scale application of database system in the SSRF accelerator control system. Based on the database interface technology, real-time data access testing and system optimization research, this article will introduce the application feasibility of database system in accelerators, and lay the foundation of database system application in the SSRF accelerator control system.

342

A neutron source driven by electron accelerator is proposed in Shanghai Institute of Applied Physics (SINAP). The facility is planned for the study of nuclear data in Thorium-Uranium cycling system, and for material research. A detailed simulation of the neutron source is performed for the program to get the neutron generation maximum economically. Several parameters of the facility, which affect the neutron yield and the neutron escape from outer surface of the target, are analyzed respectively. Besides, the yielding neutron spectrum and the escaping neutron angular distribution are calculated and discussed.

381

In this paper, a new image reconstruction algorithm employing dynamic grids technique is proposed for tomographic gamma scanning. The key feature of the algorithm is the use of adaptive grid refinement in areas that indicate large values. Simulation results show that the application of dynamic grids has a good performance in emission reconstruction with a distinct advantage in the accurate positioning of the 'hot spots' and reducing the number of grids, but doesn't achieve a tangible improvement in transmission reconstruction.

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Having studied some of the factors that influence the results of iron grade analysis during the iron ore production process, we established an online analytical system based on energy dispersive X-ray fluorescence. The system can determine the iron ore grade within 5 minutes. Compared with similar systems, this online analytical system has the ability to deal with the problems of poor sampling, poor on-site conditions for online iron ore analysis, variation in the moisture content of samples, the matrix effect and spectral drift. The system has been applied to iron ore grade evaluation in the Panzhihua Iron and Steel Company, China. Practical tests illustrated that the system can effectively improve iron ore grade evaluation.

320

In this study, we have investigated the degradation and primary radiolytic degradation mechanism of 4-tert-octylphenol (4-t-OP) by using of electron beam (EB) -irradiation. The results show that at an absorbed dose of 10 kGy and an initial concentration of 25 mg·L^-1, the degradation of 4-t-OP in a methanol/water reduction system is higher than in a acetonitrile/water oxidation system by 19.4% and higher than in an acetone/water system by 26.8%, which is due to both of ·OH and e_aq^- playing an important role in the decomposition of 4-t-OP, although the latter is more effective. The degradation rate of 4-t-OP will decrease with increment of absorbed dose in a methanol/water solution, and increase with decrement of initial concentration at a constant absorbed dose. The degradation efficiency will also decrease with the addition of anions and H₂O₂ into the solution. A system saturated with N₂ will make an increment in the degradation of 4-t-OP. The pH value of solution has been also found to affect the degradation efficiency, while the degradation is more efficient in alkaline conditions. Finally, the initial products involved in degradation reaction have been determined to be ethylbenzene, styrene, bicyclo[4.2.0]octa-1,3,5-triene, 2,2,4-trimethylpentane and p-tert-butyl-phenol, which may arise from e_aq^- attack at the position of the alkyl side chain of 4-t-OP molecule. The results have been revealed that EB irradiation is a promising method for degradation of 4-t-OP, and e_aq^- may be main reactive species to attack at the position of the alkyl side chain of 4-t-OP.

426

Purpose:Compared the performance of contrast-enhanced PET/CT and non-enhanced PET/CT for preoperatively detecting pelvic and para-aortic lymph node metastases in patients with cervical cancer.Methods:This prospective study included 72 patients with clinically M0 cervical cancer. They underwent surgery within two weeks of PET/CT imaging. Imaging consisted of a whole-body PET/CT protocol without intravenous contrast, followed by abdominal and pelvic PET/CT protocol including contrast-enhanced CT. We compared the diagnostic efficiency between the methods on per-patient and per-lesion basis.Results:Patient-based analysis showed that the sensitivity, specificity, and accuracy of contrast-enhanced PET/CT were 63.6% (14/22), 94.0% (47/50), and 84.7%(61/72), respectively, whereas those of non-enhanced PET/CT were 54.5% (12/22), 88.0% (44/50), and 77.8% (56/72), respectively, and those of enhanced CT alone were 36.4% (8/22), 80.0% (40/50), and 66.7% (48/72), respectively. Lesion-based analysis showed that the sensitivity, specificity, and accuracy of contrast-enhanced PET/CT were 77.7% (87/112), 98.7%(938/950), and 96.5% (1025/1062), respectively, whereas those of non-enhanced PET/CT were 69.6% (78/112), 97.5% (926/950), and 94.5% (1004/1062), respectively, and those of enhanced CT were 54.4% (61/112), 96.1% (913/950), and 91.7% (974/1062), respectively. Contrast-enhanced PET/CT had the best sensitivity, specificity and accuracy. Although patient-based analysis showed no significant difference between contrast-enhanced PET/CT and non-enhanced PET/CT (p =0.540, 0.295 and 0.286), the specificity and accuracy of these two methods were significantly different on lesion-based analysis (p =0.043 and 0.027).

421

We studied the structure of ¹²C through the modified Glauber model using the density distributions calculated by the relativistic mean field theory. The experimental reaction cross sections of ¹²C + ¹²C were analyzed within the MOL by a χ²–fitting procedure. The effects of the nuclear deformation on the reaction cross sections are studied. The reliable structure of ¹²C is deduced. The studies show that the conjunction of these two models will be a more effective tool to study the properties of nuclei.

384

Resonance light scattering (RLS) is a sensitive technique for monitoring scattered light induced by extended aggregates of chromophores. It has been widely used to study aggregations for its simple manipulation, high sensitivity and great versatility. Gold nanoparticles generate colorful light-scattering signals due to their unique surface plasmon resonances, hence extraordinary light scattering upon aggregation. In this paper we report a rapid and sensitive method based on gold nanoparticles and DNA aptamer to detect protein biomarkers by RLS. Thiol modified thrombin aptamer was covalently assembled to the surface of gold nanoparticles as nanobio probes. As thrombin has two specific binding sites for its aptamer, it can bridge the well dispersed nanoparticles and lead to a network of particle aggregations. The formation of aggregation ia measured by RLS, and the specific detection of thrombin at nM level is achieved. The method has good specificity.

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