Vol.21,

440

In this paper, short pulse radiation in Shanghai Synchrotron Radiation Facility (SSRF) is generated by the low momentum compaction factor (α_C) optics, and three kinds of the low-α_C optics are found, with the very low α_C being adopted by reducing dispersion in the straight section to negative value in the SSRF. Energy acceptance is selected as objective functions in nonlinear optimization rather than the second order α_C or other nonlinear driving terms. The optimal result is improved step-by-step by randomly setting harmonic sextupole strengths. Two optics modes, i.e. low positive α_C and low negative α_C, are analyzed. In order to get a large energy acceptance and only one stable point in longitudinal phase space, the low negative α_C optics is taken as an operation mode for the short pulse radiation in the SSRF.

490

Degradation of low-concentration p-nitrophenol (p-NP) aqueous solution was carried out in 254/185 nm photolysis. The effects of Mn²⁺, pH value, O₂ and O₃ on the degradation efficiency have been investigated. It was observed that the singlet oxygen scavenger Mn²⁺ did not affect the degradation of p-NP. In acidic and alkaline solutions, the degradation efficiency was enhanced in comparison to that in neutral solution. The presence of O₂ dramatically promoted the degradation of p-NP, while that of O₃ impeded it.

582

Cu₂O nanocrystals were synthesized by irradiating an aqueous solution of CuSO₄·5H₂O (1.25g), polyvinyl alcohol (PVA, 0.8 g), and isopropanol (3.1 mL). The products were characterized by powder XRD, TEM and SEM. Methyl orange degradation under visible light using the Cu₂O nanocrystals as catalyst was studied by UV-Vis absorption method. The results show that the products are nanocrystals of pure Cu₂O. Morphology and size of the nanoparticles are affected by the irradiation dose and pH value of the initial solution. Octahedral Cu₂O nanocrystals of 116 nm in size can be obtained at the initial pH of 8.0 and 280-kGy irradiation. The nanocrystals have excellent catalytic activity for photodegradation of the methyl orange solution bubbled at the air-flow rate of 750 mL·min^–1, due to the large {111} facets of octahedral Cu₂O particles.

529

In this article, radiation effects and annealing characteristics of a bipolar analog-to-digital converter (ADC) are investigated in different biases and dose rates. The results show that ADC is sensitive to both the bias and dose rate. Under high-dose-rate irradiation, the ADC functions well, while under low-dose-rate irradiation, the parameters of ADC change obviously at low dose level, and the damage is significant at zero bias. Combining the fringing field with the space charge model, the underlying mechanism for this response is discussed.

538

In this paper, a time of flight neutron reflectometer model is proposed. According to the original objective inputting physical parameters and expectations, computer simulation was done by McStas package. With the open slit, neutron flux at sample position was about 1×10⁵ n·cm^–2·s^–1, and the optimal resolution could reach 0.5%. The results show that the model has a good performance. The design of this model can be an instruction for neutron reflectometer construction or project analysis in the future.

492

In this paper, uranium targets are prepared by electro-deposition. Hydrated uranium dioxide films are electrodeposited into stainless steel plates using uranyl nitrate in ammonium oxalate solution. The results show that the deposition efficiency of the uranium depends on many parameters, such as pH value, supporting electrolyte, current density, and cell design. The uranium films were characterized by infrared spectrum, scanning electron microscope, and X-ray spectrum. The uranium films, with a yield of 98%, are in the thickness of about 6 mg·cm^–2.

430

Due to interesting therapeutic properties of ¹⁵³Sm and antineoplastic antibiotic, bleomycin (BLM), ¹⁵³Sm-bleomycin (¹⁵³Sm-BLM) was developed as a possible therapeutic compound using ¹⁵³SmCl₃ and BLM. The ¹⁵³SmCl₃ was obtained by thermal neutron flux (5×10¹³ n·cm^–2·s^–1) of an enriched ¹⁵²Sm₂O₃ sample, dissolved in acidic media. Under optimized conditions (room temperature, 45 min, 0.1 mg bleomycin for 740–3700 MBq ¹⁵³SmCl₃) a radiochemical purity over 98 % was obtained shown by HPLC (Specific activity = 55 TBq/mM). The ¹⁵³SmCl₃ and ¹⁵³Sm-BLM were administered into wild-type rats up to 96 h followed by biodistribution. The SPECT imaging of labeled compound in wild-type rats was performed and significant image pattern was observed for a radiolabeled bleomycin compound. The ¹⁵³Sm-BLM is a potential therapeutic compound and our experiments on this compound have shown satisfactory quality, and stability suitable for future therapeutic studies.

583

The pharmacologic characteristics of ⁹⁹Tc^m-N-ethyl-N₂S₂-memantine, an NMDA receptor imaging agent, was investigated. It was prepared by a one-step reaction from N-ethyl-N₂S₂-memantine. The affinity and specificity were determined by radio-ligand receptor binding assay (RRA). Biodistribution in vivo in mice was performed. The results showed that ⁹⁹Tc^m-N-ethyl-N₂S₂-memantine bound to a single site on NMDA receptor with a K_d of 584.32 nmol/L and a B_max of 267.05 nmol/mg. A competitive analysis showed that such specific binding could be inhibited by specific inhibitors of NMDA receptor, such as ketamine and (+)-MK-801. The biodistribution exhibited rapid uptake and favorable retention in mice brains. The major radioactivity was metabolized by the hepatic system. A two-compartment model of C = 4.49e^–0.083t + 1.42e^–0.0016t was established, and the half life was 8.35 min in blood. In conclusion, the new radio-ligand ⁹⁹Tc^m-N-ethyl-N₂S₂-Memantine has a moderate affinity and specific binding to NMDA receptor, and can easily cross the blood-brain barrier (BBB). Therefore, it may be a potential NMDA receptor imaging agent.

616

It is difficult to develop image reconstruction algorithms for tomographic gamma scanning based on drummed radioactive residues or wastes. In this paper, a novel reconstruction algorithm of transmission image for tomographic gamma scanning is proposed. It is based on the conventional transmission equation and equivalent gamma-ray track length modified by a Monte Carlo method. The algorithm is implemented by simulating the samples on the established platform. For the verification experiments of the algorithm, several cubic voxel samples were designed and manufactured. Experimental tests were conducted. The tomographic gamma scanning of transmission images is compared with the linear attenuation coefficients by the simulated values and experimental data with the algorithm and the reference values. The results show that the absolute relative errors of the reconstructed images are less than 5%.

464

Soil radon measurement of high stability and sensitivity is widely applied, and in some applications, such as in uranium prospecting, ²²²Rn should be distinguished from ²²⁰Rn. To meet this requirement, a practical method based on soil radon diffusion and accumulation theory to measure soil radon by Alpha Particle Spectroscopy (α-PS) is discussed in this paper. The α-PS measurement method can effectively overcome the effects of ²²⁰Rn and its daughters (²¹⁶Po, ²¹²Bi, ²¹²Po). The system can eliminate the impact of soil radon field disturbance and non-uniformity through soil radon static diffusion. Radon daughters (²¹⁸Po, ²¹⁴Po) are accumulated under the action of an electrostatic force, which not only enhances the measurement sensitivity, but also increases robustness of the measurement. Simultaneous measurement of multiple points can increase the comparability of measurement data and the measurement efficiency. Experimental data shows that the soil radon measurement method was robust. So it has wide applications such as in geological prospecting, in fissure groundwater exploration and in ground subsidence inspection.

447

Technical diagnosis system (TDS) is an important subsystem to monitor status parameters of EAST (experimental advanced superconducting tokamak). The upgraded TDS data monitoring system is comprised of management floor, monitoring floor and field floor. Security protection, malfunction record and analysis are designed to make the system stable, robust and friendly. During the past EAST campaigns, the data monitoring system has been operated reliably and stably. The signal conditioning system and software architecture are described.

544