Vol.14,

An experimental study on nondestructive X-ray imaging of inner structure of soft tissues in phase contrast has been conducted with Beijing Synchrotron Radiation Facility (BSRF). Modification to the beamline setup was made to enlarge the X-ray beam section and consequently larger samples could be imaged. In-line setup was employed for experiments. Results on a series of samples were given and soft-tissue details of less than 50μm inside a fresh goldfish were obtained. Diagnosis of tumor in its early stage was also investigated taking SD rats as the model. Tumor at the size of ~100μm was observed. Potential of this technique in clinic diagnosis was discussed.

392

The wake field, impedance and output signal for SSRF BPM have been calculated and analyzed by using the numerical simulation code of MAFIA. The narrow-band impedance of BPM arising from formation of resonance in its cavity like structure either is harmful to beam or limits the performance of BPM itself, and should be reduced to tolerable levels. The calculated results show that there are three main peaks in the impedance spectrum of the SSRF BPM prototype, and two of which are above the limit. After lots of simulations for different shapes of the BPM button, a new structure of SSRF BPM have been found, and there is only one main peak, which is under the limit, in the impedance spectrum. Its output signal also meets the requirement.

314

During the Phase II project of NSRL, a turn by turn BPM (Beam Position Monitor) system is proposed for storage ring diagnostics which engages log-ratio electronics circuit to measure machine properties of the HLS (Hefei Light Source) storage ring. The log-ratio processor works at 408MHz, twice the RF frequency of HLS. Modern logarithmic amplifiers with wide dynamic range, great bandwidth, good logarithmic conformance, and low cost are attractive for beam position measurements. Injection kicker and the stripline-electrode resonant exciting methods are used to excite beam for nonlinear beam dynamics and phase space studies of stored beam. Up to 2 seconds of data acquisition is ensured. In this paper we present the performance of each component and preliminary test results of the turn-by-turn BPM system.

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Si/SiGe/Si heterostructures grown by ultra-high-vacuum chemical vapor deposition (UHVCVD) were characterized by Rutherford backscattering/Channeling (RBS/C) together with high resolution X ray diffraction (HRXRD). High quality SiGe base layer was obtained. The Si/SiGe/Si heterostructures were subject to conventional furnace annealing and rapid thermal annealing with temperature between 750 ^oC and 910 ^oC. Both strain and its relaxation degree in SiGe layer are calculated by HRXRD combined with elastic theory, which are never reported in other literatures. The rapid thermal annealing at elevated temperature between 880 ^oC and 910 ^oC for very short time had almost no influence on the strain in Si_0.84Ge_0.16 epilayer. However, high temperature (900 ^oC) furnace annealing for 1h prompted the strain in Si_0.84Ge_0.16 layer to relax.

484

Polycarbonate foil stacks were irradiated with 2.1 GeV Kr ions under vacuum at room temperature. The modifications in chemical structure induced by the irradiation were studied by means of Fourier transform infrared (FTIR) and ultraviolet visible (UV/VIS) spectroscopies. FTIR measurements reveal that material degradations through bond breaking are the main effects. Alkyne end groups are produced by the irradiation. UV/VIS measurements indicate a shifting of the absorption edge from ultraviolet towards visible, and a strong increase of absorbance in the ultraviolet and visible regions. The changes in absorbance induced by the irradiation at wavelengths of 380 nm, 450 nm and 500 nm scale well with S_eⁿ (S_e is electronic energy loss) where the value of n increases from 1.69 to 2.02 with increasing of the wavelength. The results are briefly discussed.

295

The paper describes the solvent extraction of trace thorium from hydrochloric acid media by 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) using a radioactive tracer technique. The percent extraction of thorium was studied as a function of acidity, PMBP concentration and equilibrium time. The back-extraction behavior of thorium from the organic phase was also tested. Separation of thorium was performed from fission products produced in 14 MeV neutron bombardment of natural uranium by employing the PMBP extraction procedure. The gamma-ray spectra of the separated thorium fractions show that thorium can be separated from most of fission products and a large amount of uranium.

276

⁶⁷Ga-EDTMP was synthesized in a single step by adding ⁶⁷GaCl₃ to EDTMP solution. Dependences of the radiolabeling yield of ⁶⁷Ga-EDTMP on EDTMP concentration, pH and reaction time were examined. Under the optimum conditions, the radiolabeling yield of ⁶⁷Ga-EDTMP was more than 97%. A biodistribution experiment in mice showed that ⁶⁷Ga-EDTMP was mainly absorbed by skeleton and reached 13.25% at 0.5 h after injecting, then kept a high level in 72 h with a maximum value of 16.82% at 48 h. The results suggest that ⁶⁷Ga-EDTMP might be a potential bone pain palliation radiopharmaceutical due to its high skeletal uptake, rapid blood clearance and relatively low soft-tissue absorption. But further work must be done to determine whether ⁶⁷Ga-EDTMP is useful in the treatment of painful osseous metastases.

298

This study aimed at the effect of γ-emitting radionuclide ¹⁰³Pd on the proliferation and apoptosis of vascular SMCs (smooth muscle cells) in vitro. The cavy aortic smcs were cultured with culture medium M-199. The experiments were carried out in two groups, one for proliferation test and the other for apoptosis test. In each group, ¹⁰³Pd solutions with various radioactivities were respectively added to the culture solution to irradiate SMCs for 72 h, while non-radioactive palladium solution was added to the control. ³H-thymidine incorporation test and liquid scintillator were used to detect the effect of ¹⁰³Pd on the proliferation of SMCs. Flow cytometer was used to detect the apoptotic SMCs. The inhibition rate of SMCs proliferation by 1.85 MBq ¹⁰³Pd solution was 2.3%, which was not significant, while the inhibition rate increased from 41.6% to 91.3% as the ¹⁰³Pd activity increased from 7.40 MBq to 37 MBq. The apoptosis rate of SMCs was extremely low (less than 4.0%) by ¹⁰³Pd with activity from 1.85 MBq to 37 MBq. The results suggest that the proliferation of SMCs can be repressed effectively in a dose-dependent fashion by ¹⁰³Pd in vitro. The mechanism of its inhibiting over neointima proliferation is likely to inhibite SMCs proliferation rather than to induce its apoptosis by ¹⁰³Pd. ¹⁰³Pd can be used as a γ-emitting intravascular brachytherapy radionuclide to inhibit SMCs proliferation.

303

The biodistribution of ¹²⁵I-BMIPP and the variation of myocardial uptake of ¹²⁵I-BMIPP using the metabolic intervention drug were reported. Myocardial uptake of the ¹²⁵I-BMIPP in rats showed a peak of 5.70ID%/g at 2 min. The ratios of myocardium to blood, to liver and to lung at 30min were 3.40, 2.64 and 2.88 respectively. The initial elimination half time of 4.0min in rabbits was in accordance with the half elimination time of free fatty acid from blood. Myocardial uptake of ¹²⁵I-BMIPP in the group of glucose-insulin was significantly increased (p<0.05) than those of the normal control. In vivo and in vitro binding test for ¹²⁵I-BMIPP to HSA showed a rather constant level of activation up to 2h. Partition coefficients (lgp) were 1.93 and 1.68, respectively.

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281

A prototype of elemental analyzer for coal has been developed by using a PFTNA (pulse fast thermal neutron analysis) system. The PFTNA technology is based on the reactions such as (n, γ), (n, n’γ), (n, pγ), etc. by examining the characteristic gamma rays emitted. In our prototype a pulsed neutron generator provides 14 MeV pulse neutrons, which contribute to the separation of spectrum II (the sum of capture and activation spectrum) from spectrum I (the sum of inelastic, capture and activation spectrum), and thus to the measurement of C and O contents in coal. Data management is completed by computer program using the least-square regression method. The experiment in Changshan power plant for 3 months showed that the precision of calorific value, whole water, volatile content and ash content is 0.5 kJ/kg, 1.0 wt%, 2.0 wt% and 1.5 wt%, respectively.

432

The 150kV bouncer modulator is designed to drive the 10MW multi-beam klystron for the DESY TESLA Test Facility. The modulator is different from the 10kV modulators previously built at Fermilab. First, the new 150kV bouncer modulator has no transformer, so the modulator circuit is simplified and the output waveform is improved well. Second, the bouncer circuit has been changed to fit the output need, which is the most significant challenge. This paper gives the design of the 150kV long pulse bouncer modulator.

288

The γ radiation level, alpha potential energy of thoron and alpha surface contamination level at a mantle factory in the east of Zhejiang Province are reported. The measured results show that the additional annual effective dose equivalent absorbed by the worker in some workshops of the factory was higher than 15 mSv—management limit. The alpha surface contamination on the workers' hands in some workshops was 10 times more than the management limit of National Standard (0.04Bq/cm²). The mantle factory's main danger to body was internal irradiation of α rays from thoron aerosol.

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