There have been numerous papers over the past 10 years dealing with X-ray protection in the range from 500 to 2,000 kv [1 to 6]. The data from these papers differ somewhat, because the conditions of the experiments were not always the same and therefore cannot be readily correlated. Part of this has been attributed to differences in the high-voltage wave form and inherent filtration for the sev...

Single-cycle terahertz fields generated by coherent transition radiation from a relativistic electron beam are used to study the high field optical response of single crystal GaAs. Large amplitude changes in the sub-band-gap optical absorption are induced and probed dynamically by measuring the absorption of a broad-band optical beam generated by transition radiation from the same electron bunc...

The refraction of a localized narrow beam is significantly different from that of a plane wave. As the beam width decreases to be in the order of the wavelength, the refraction behavior deviates noticeably from Snel’s law, and when the width of a light beam is smaller than about one fifth of the wavelength of the incident light, finite-difference time-domain simulations demonstrate that refract...

Using a new technique to generate cold electron beams, an electron-beam positron-plasma experiment was performed in a previously unexplored range of energies. An electron beam, formed from a thermalized room-temperature electron plasma, is transmitted through a positron plasma stored in a quadrupole Penning trap geometry. The transit-time instability, which is excited by the beam, was previousl...

Tumours and other superficial targets are often treated with electron beams in radiotherapy. The build-up dose and the therapeutic range of electrons are controlled by selecting the electron energy and by using a water-equivalent bolus placed on the skin. Currently, the shaping of clinical electron beams is often done via low melting point alloy block inserts individually made for each patient....

The tumoricidal mechanisms of microbeam radiation therapy, and the more recently proposed minibeam radiation therapy, for the treatment of brain tumors are as yet unclear. Moreover, from among the various parameters of beam geometry the impact of changing the beam width is unknown. In this study, suppression of tumor growth in human glioma cells implanted in mice was evaluated experimentally us...

We have constructed a computer controlled translational couch to administer total body irradiation reproducibly and safely. The system has replaced the previous stationary anterior-posterior technique in our institution and 30 plus patients have been treated with it so far. In this technique, patients comfortably lie on a couch in supine and prone positions and are transported slowly through a ...

Adjustable narrow band holographic reflective filter with the absolute diffraction efficiency about 95% has been recorded in the volume of photo-thermo-refractive glass Attenuation up to 20 times of transmitted beam was observed. Advantages of holographic filters in inorganic glass for laser power attenuation are discussed. © 2003 Optical Society of America OCIS codes: (230.1480) Bragg reflecto...

Introduction: Optical CT scanning of radiochromic gel dosimeters is a method for true 3D dosimetry, which is becoming increasingly needed as radiation therapy techniques become more advanced. Optical CT has developed from slow pencil beam laser scanners to fast cone-beam scanners using cameras. However, scattered light perturbs these broad-beam scanners, resulting in cupping artifacts and loss ...