[en] A review of early microbeam apparatuses used to study the biological responses caused by irradiation was given along with a summary of the investigation results on the single cell experiments. The deficiencies of the early apparatus were analyzed and used to guide the charged particle microbeam design

No abstract available

[en] A 2.45 GHz electron cyclotron resonance ion source with permanent magnets has been developed. Its outline dimension is 160 mm in diameter and 90 mm in height, the discharge chamber's dimensions is 70 mm in diameter and 50 mm in height. The microwave window is made of a φ 50 mm × 10 mm BN disk and two φ 30 mm × 10 mm ceramic disks. This ion source adopts a three-electrode extraction system and works in the pulsed mode. When the microwave input power is 300 W, the air inflow is 0.4 mL/min, a more than 30 mA peak current of the nitrogen beam can be extracted from a 5 mm emission aperture at 100 kV extraction voltage. The diameter of the beam uniform area on the working plane is more than 200 mm. (authors)

[en] Nitrobenzene (NB), a widely used industrial chemical, is a likely human carcinogen. Many dietary constituents can suppress the DNA-adduction, acting as the inhibitors of cancer. In this study, we investigated the inhibitory effects of vitamin C (VC), vitamin E (VE), tea polyphenols (TP), garlic squeeze, curcumin, and grapestone extract on NB-DNA and NB-hemoglobin (Hb) adductions in mice using an ultrasensitive method of accelerator mass spectrometry (AMS) with ¹⁴C-labelled nitrobenzene. All of these dietary constituents showed their inhibitory effects on DNA or Hb adduction. VC, VE, TP and grapestone extract could efficaciously inhibit the adductions by 33-50%, and all of these six agents could inhibit Hb adduction by 30-64%. We also investigated resveratrol, curcumin, VC and VE as inhibitors of NB-DNA adduction in vitro using liquid scintillation counting technique. These agents in the presence of NADPH and S9 components also pronouncedly blocked DNA adduction in a dose-dependent profile. Our study suggests that these seven constituents may interrupt the process of NB-induced chemical carcinogenesis

[en] The charged-particle microbeam provides a unique opportunity to precisely control both the dose to individual cells and the localization of dose within the cell. In the Gray Laboratory, both the performance of the detection system and the targeting system has been assessed for 3.5 MeV ³He²⁺ ions. Using an 18 μm transmission scintillator and a photomultiplier tube as the particle detection system, detection efficiency is higher than 99%. When a 5 μm collimator is used, the overall targeting accuracy (which includes the error associated with target finding and alignment) is <2.8 μm for 98.7% of hits

[en] The ion beam optics of a microwave ion gun for a focused ion beam (FIB) system is investigated numerically. Considering the ion beam optics of the gun as a two-stage acceleration system consisting of plasma electrode and Orloff-Swason lens, effects of some primary parameters on the beam divergence are examined. The results show that beam divergence of the system depends mainly on the extraction perveance and voltage ratio, and a minimum beam divergence can be obtained under optimum conditions

[en] A small cavity-type microwave ion source used in the device of ion beam cell etching has been fabricated, which consists of a quartz discharge tube, a coaxial cavity and a two -grid extractor enclosing one end of tube. The plasma column of the source was sustained by surface wave excited by the cavity. In order to increase ion current extracted from the end of the column, two different quartz tube configurations, a straight tube geometry with inner diameter of φ7.0 mm and the same straight tube inserted by a liner tube with inner diameter of φ5.0 mm at one end, has been operated to verify our theory. For nitrogen, ion current density of 48.4 mA/cm² and 91.7 mA/cm² have been extracted from sources respectively, when they are operated at a frequency of 2.45 GHz and a incident power of 93 W. This plasma source is of many advantages, such as small volume, simple configuration and high density of ionized electron in the plasma with good stability and reproductivity over a large pressure range, etc

[en] A remote control system for the ECR ion source and LEBT device based on Siemens S7-300 PLC is introduced in the paper. A PROFIBUS-DP is used to exchange message between the host-computer and PLC. Human Machine Interface (HMI) is developed by Siemens WinCC software, with the functions of interlock, control, and data acquisition. Some detail problems such as structure, reconstructing incontrollable equipment, hardware and software designing are presented. (authors)

[en] Plasma discharge induced by surface-waves in a compact cavity-type microwave ion source is investigated and the model is built up. The axial density profile and the dispersion property of the plasma column are described systematically in consideration of the geometric parameters and the discharge parameters of the discharge tube, such as: the gas pressure, flow rate, the wave angular frequency, and so on. The numerical calculations show that the axial density curve and the wave dispersion acutely depend on the number γ(γ = 1 + d/R, R is the radius of the plasma column, d is the thickness of the tube), the permittivity ε_d and the gas flow and direction. The model is tested with the experimental data determined by A. Sola and S. Davlaud and agreement is achieved

[en] This paper presents new beam test results for O"+ beam on high current Integral Split Ring Radio Frequency Quadruple (ISR RFQ) accelerator. After the upgrading, a new designed 2.45 GHz O"+ ECR Ion Source can provide a beam with macro-pulse peak current of 4 mA at eh injection point behind a 15 mm diaphragm, whose O"+ factor is 60%-80% varied with gas flow rate and the normalized rms emittance is less than 0.15 πmm·mrad. The accelerated O"+ beam current goes up to 2 mA with the transmission of about 80% at 45 kW RF power with duty factor 1/6 (pulse duration of 1 ms and repetition frequency of 166 Hz). The upgraded RF power system includes low level RF pulse modulation amplifier, AGC, 3 W and 20 W preamplifiers, 1 kW driver and 30 kW final amplifier, which can output nearly 50 kW in pulsed mode. The vacuum has been improved, too. The upgraded 1 MeV ISR RFQ can be used as the beam injector of a new designed SFRFQ accelerating system, which is under the construction at Peking University, (authors)