The Compton camera can collect SPECT data with high efficiency due to electronic collimation. The data acquired from a Compton camera are projections of source activity along cones and are approximated in this paper by cone-surface integrals. This paper proposes the use of an orthogonal spherical expansion to convert the cone-surface integrals into plane integrals. The conversion technique is e...

This report describes studies performed in the framework of the Collimation Task Force organized to support the work of the second International Linear Collider Technical Review Committee. The post-linac beam-collimation systems in the TESLA, JLC/NLC and CLIC linear-collider designs are compared using the same computer code under the same assumptions. Their performance is quantified in terms of...

We present theory for coherent effects observed in crystal collimation experiments that is in good quantitative agreement with RHIC and Tevatron data. We show that coherent scattering in a bent crystal strongly amplifies beam diffusion, with an effective radiation length shortened by orders of magnitude compared to amorphous material. This coherent scattering could replace the traditional amorp...

We present a new conceptual and optical design for the Next Linear Collider post-linac collimation system. Energy collimation and passive protection against off-energy beams are achieved in a system with large horizontal dispersion and vertical betatron functions. Betatron collimation is performed in a relatively low-beta (FODO-like) lattice in which only thin spoilers intercept particles near ...

background the use of shielding tools and x-ray beam collimator has extensively been advocated as effective methods to reduce radiation exposure to patients underwent radiological procedures. the aim of this study was to address the use of these protection measures during infant chest radiography. material and methods 348digital and/or analogue infant chest radiographs were reviewed that perfor...

PURPOSE To investigate the range of collimation errors in x-ray rooms and to calculate their possible effects on the radiation dose for anteroposterior pelvic examinations. METHODS A collimator test tool was suspended at 3 heights (14, 21, and 28 cm) above the table Bucky in 9 x-ray rooms. Heights corresponded to the typical patient thickness (mean, ± 2 SD) of 67 patients undergoing anteropos...

Simulations of the LHC collimation system have been carried out in previous years with the well known SixTrack code with collimation features. MERLIN is a C++ accelerator physics library that has been extended to perform collimation studies. The main features of the code are: its modular nature, allowing the user to easily implement new physics processes such as resistive wakefields and synchro...

The high beam intensities in the next linear collider can damage the collimation system jaws if a failure of the electronic machine protection system allows the acceleration of a mis-launched pulse. We are developing a prototype collimator that will allow a new jaw surface to be moved into place after beam damage. We are also developing a prototype collimator based on continuously reforming the...

A photonic crystal polarization beam splitter based on photonic band gap and self-collimation effects is designed for optical communication wavelengths. The photonic crystal structure consists of a polarization-insensitive self-collimation region and a splitting region. TMand TE-polarized waves propagate without diffraction in the self-collimation region, whereas they split by 90 degrees in the...