Shi-Biao Tang

Geant4 used in medical physics and hadrontherapy technique

Abstract This article mainly presents the application of Geant4 package (Geant4.7.0, 2005), developed by CERN (the Center of European Research of Nucleus), in medical physics and a novel technique, namely, hadrontherapy. The distribution of energy deposition in a water model by different radiation beams was also given. The results show that the distributions for proton beams are completely different from those for other radiation beams. Charged particles like protons exhibit little scattering when they penetrate the matter and give the highest energy deposition near the end of their range just before they reach the resting state. These characteristics permit very precise control of the shape of the energy distribution inside the patients body.

Energy deposition of γ-ray in different instances and its influence on energy detection

Abstract In this paper, we simulate γ ray energy deposition for different incident energies with four different models using the tool GEANT4 (Geant4.7.0, 2005) developed by CERN (the Center of European Research of Nucleus). The results we obtained indicate that there are different peak values for different incident energies. That is, we can differentiate the incident energy accurately if the detector can determine the peak value accurately. This is meaningful for the geometrical configuration of the detector to get the most probable distribution (MPD) of energy deposition for different incident energies. According to the simulation, we can insert certain slices with large absorption coefficient to obtain a better MPD of energy deposition which will not alter the shape of the energy deposition.

A novel compact real time radiation detector

A novel compact real time radiation detector with cost-effective, ultralow power and high sensitivity based on Geiger counter is presented. The power consumption of this detector which employs CMOS electro circuit and ultralow-power microcontroller is down to only 12.8 mW. It can identify the presences of 0.22 μCi (60)Co at a distance of 1.29 m. Furthermore, the detector supports both USB bus and serial interface. It can be used for personal radiation monitoring and also fits the distributed sensor network for radiation detection.

Two-dimensional X-ray imaging using plastic scintillating fiber array

Due to its low cost, flexibility and convenience for long distance data transfer, plastic scintillation fiber (PSF) have been increasingly used in building detectors or sensors for detecting various radiations and imaging. In this work, the performance of using PSF coupled with charge-coupled devices (CCD) to build area detectors for 2D X-ray imaging is studied. We describe the experimental setup and show the obtained images from CCD. Modulation Transfer Function (MTF) of the PSF array is also presented and compared to earlier reports.

Numerical simulation of high-energy neutron radiation effect of scintillation fiber

Abstract Due to their low cost, flexibility, and convenience for long distance data transfer, plastic scintillation fibers (PSF) have been increasingly used in building detectors or sensors for detecting various radiations and imaging. In this paper, GEANT4 Monte Carlo simulation tool was used to obtain some radiation effects of PSF under high-energy neutron irradiation. BCF-20, a plastic fiber material, produced by Saint-Gobain, was used in the simulation. The fiber consists of a core scintillating material of polystyrene and an acrylic outer cladding. Incident neutrons produce energy deposition in fiber through neutron induced recoil proton events. The relationships between energy deposition efficiency and fiber length, fiber radius and incident neutron energy are presented. The variation with those parameters and parameter selection are also analyzed.

A simulation study of the DQE of a linear plastic scintillating fiber array for hard gamma-rays

The detector quantum efficiency (DQE) of a linear plastic scintillating fiber (PSF) array coupled with a charge-coupled device (CCD) for hard gamma-ray imaging is studied using a Monte Carlo simulation. The focus is on the energy from a few MeV to about 12 MeV. The excellent characteristic of PSF offers a method to balance the detection efficiency and spatial resolution. Our simulation results indicate that the modulation transfer function (MTF) for different energies become almost the same below the certain frequency and the DQE should be better at lower frequency for imaging lower incident energy. These characteristics suggest that the PSF may be useful for detecting high energy gamma-rays.

Some characteristics of X-ray imaging for energy region of over 100 keV using plastic scintillation fiber array

Abstract In this work, characteristics of using PSFs (plastic scintillation fibers) coupled with CCD (charge-coupled devices) to build area detectors for high energy X-ray imaging are studied with a Monte Carlo simulation, which cover an energy range of a few hundred keV to about 20 MeV. It was found that the efficiency of PSF in detecting X-ray with energy above a few hundred keV is low. We can use large incident flux to increase the output signal to noise ratio (SNR). The performance can also be improved by coating PSF with X-ray absorption layers and the MTF of the system is presented. By optimizing the absorption layer thickness, the crosstalk of the area detector built with PSF decreases.