Introduction Model supported catalysts on flat surfaces form an important link between single crystal surfaces and real world supported catalysts. The use of nanofabrication techniques to prepare such model catalysts has received a lot of attention in recent years [1]. In the present study Pt/TiO2 catalysts have been fabricated using e-beam lithography (EBL) and used to characterize the electri...

The Budker-Chirikov instability (BCI) in a two-beam electron-ion system is researched. The BCI is due to the interaction of the slow cyclotron wave of the electron beam with the fast betatron wave of the ion beam. The electron-ion system consists of a high current relativistic electron beam propagating co-axially with a nonrelativistic ion beam in a drift tube. The external radii of the electro...

Introduction: The aim of this study was to investigate the initial electron beam parameters for Monte Carlo model of 6MV photon beam produced by Siemens Oncor® linear accelerator.   Materials and Methods: In this study, the EGSnrc Monte Carlo user codes BEAMnrc and DOSXYZnrc were used. The beamnrc code were used for modelling of a 6 MV photon beam produced by...

An electron beam microbunched on the optical wavelength scale of ø2.5 mm by an inverse free electron laser accelerator was observed. The optimum bunching was achieved for a 1% energy modulation of a 32 MeV electron beam with 0.5 GW CO2 laser power. The microbunching process was investigated by measuring the coherent transition radiation produced by the energy modulated electron beam. A quadrati...

Radiation is becoming widely available to treat tumors in veterinary patients. Orthovoltage machines capable of delivering low energy external beam radiation are less versatile than linear accelerators and cobalt-60 machines that deliver megavoltage radiation. In addition, electron beam capabilities that are available with some linear accelerators allow more targeted treatment in our smaller pa...

The coordinate and energy distributions of the electron beam density at the Advanced Light Source have been obtained from measurements of the beam lifetime at various storage-ring apertures in the horizontal and vertical planes. It is shown that these distributions have a Gaussian core extended approximately up to five rms beam sizes. Beyond this point the electron density is defined by the ele...

Helical tomotherapy is a dedicated intensity modulated radiation therapy (IMRT) system with on-board imaging capability (MVCT) and therefore differs from conventional treatment units. Different design goals resulted in some distinctive radiation field characteristics. The most significant differences in the design are the lack of flattening filter, increased shielding of the collimators, treatm...

A pulsed, 20 kv electron beam is focussed upon a vapor-deposited thermocouple, and the resulting temperature vs. time response is studied. The experimental data show much scatter, but are consistent with the theoretical prediction that the characteristic thermal response time T is proportional to d , where d is the beam diameter at the thermocouple. From these data, for the soft-glass substrate...

In convergent-beam electron diffraction (CBED) a highly convergent electron beam is focussed on to a small (~< 50 nm) area of the sample. Instead of the diffraction spots that are obtained in the back focal plane of the objective lens with parallel illumination in conventional selected-area electron diffraction, CBED produces discs of intensity. The point group can be determined uniquely from t...