Introduction The ZAP-X is a novel self-contained and first-of-its-kind self-shielded therapeutic radiation device dedicated to brain and head and neck radiosurgery. By utilizing a 2.7-MV linear accelerator and incorporating a design in which a beam stop and major mechanical elements serve a radiation shielding function, the Zap-X does not typically require a radiation bunker. The unique collima...

In order to have highly flexible secondary beamlines collimation is crucial. Collimators are blocks of material placed along the beamline that let main beam pass within collimator aperture limits, while most particles beyond it interact in and gets absorbed or loses enough energy be deflected away from core by magnets downstream. Some can at edge collimators accepted beam, creating background f...

A rotatable collimator is proposed for the LHC phase II collimation upgrade. When the beam crosses the collimator, it will excite trapped modes that can contribute to the beam energy loss and power dissipation on the vacuum chamber wall. Transverse trapped modes can also generate transverse kicks on the beam and may thus affect the beam quality. In this paper, the parallel eigensolver code Omeg...

We assessed improvements in performance in detection and estimation tasks due to a novel brain single photon computed tomography collimator. Data were acquired on the CeraSPECT scanner using both new and standard collimators. The new variable focusing collimator SensOgrade samples the projections unequally, with central regions more heavily represented, to compensate for attenuation of counts f...

Introduction:In an ideal parallel-hole collimator, thickness of septal material should be sufficient to stop more than 95% of incident photons. However, some photons pass the septa without interaction or experience scattering before they reach the detector. In this study, we determined different contribution of collimator responses consist of geometrical response, septal penetr...

In single photon emission computed tomography (SPECT), pinhole and cone-beam collimators are used for small object imaging. It is accepted that a pinhole collimator should be used if the object is very small, and the cone-beam collimator should be used if the object is larger. This paper presents criteria to determine which collimation geometry is more advantageous in terms of spatial resolutio...

Using a recently developed time domain numerical approach we calculate the short-range geometric wakefields of 3D collimators and compare with analytical models. We find, in the diffractive regime, that the transverse mode kick factor can be approximated from the change in field energy between the beam pipe and the collimator if the collimator is long, or using a “field clipping” estimate if it...

Introduction: In nuclear medicine, the use of a pixelated semiconductor detector such as CZT is an of growing interest for introducing new devices. Especially, the spatial resolution can be improved by using a pixelated parallel-hole collimator with equal holes and pixel sizes based on the pixelated detector. The purpose of this study was to compare the effect of pixelated and ...

This paper is aimed to investigate the design of an optimized neutron radiography system that utilizes the flux of a reactor. Moderation, collimation aspects are studied. A Monte Carlo code, MCNP4C, was utilized to achieve a maximum and more homogenous neutron flux in the collimator outlet next to the image plane, taking into account geometric characteristics. It was possible to obtain a normal...