The physical mechanisms driving the collimation of dense plasma jets created by low-energy ( approximately 0.6 J) laser pulse irradiation of triangular grooves were studied for different target materials using soft-x-ray interferometry and hydrodynamic code simulations. The degree of collimation of jets created by irradiating C, Al, Cu, and Mo targets at intensities of I=1x10(12) W cm(-2) with ...

background: in radiation therapy, the sparing of normal tissues can be performed using either multi-leaf collimators or cerrobend blocks. the current work focuses on the physical characteristics of cerrobend blocks including attenuation coefficient, effective penumbra width and isodose curves undulation in penumbral regions. materials and methods: all measurements were performed using a dual en...

I studied experimentally the beam self-collimation and splitting in two-dimensional microwave photonic crystals. Using a microwave photonic crystal fabricated from alumina rods, I present an experimental proof of principle for an earlier theoretical proposal [A. Matthews et al., Opt. Commun. 279, 313 (2007)] of a photonic crystal beam splitter based on the self-collimation effect.

Introduction: Collimating the primary beam to the area of diagnostic interest (ADI) has been strongly recommended as an effective method to reduce patient’s radiation dose and to improve image quality during radiology practice. Lack or inadequate collimation results in excessive radiation dose to patients and deterioration image quality.Objective: To assess the quality of beam collimation dur...

We calibrated a scintillation camera for the counts-to-activity conversion factor, CF, by measuring a phantom consisting of a sphere containing a known 131-I activity placed within an elliptical cylinder. Within a 3D OSEM reconstruction algorithm, we employed a depth-dependent detector-response model based on smooth fits to the pointsource-response function. Using the ultra-high-energy (UHE) co...

There is an increased risk of pulmonary embolism (PE) in patients with malignancy. This increased risk is fourfold above the general population and is further increased if the patient is receiving chemotherapy [1–6]. Between 4 and 28% of cancer patients will develop thromboembolic disease depending on their tumour type and stage [1]. A significant proportion of patients with PE will present wit...

The four-dimensional transport of the transverse phase space of the extracted beam was calculated for the CAPRICE electron cyclotron resonance (ECR) ion source at GSI. The axial magnetic field adds an angular momentum to the extracted beam, resulting in a strongly x-y coupled beam. The report presents multi-particle tracking simulations, and the results illustrate that the beam brilliance can b...

We introduce the theoretical criterion for achieving three-dimensional self-collimation of light in a photonic crystal. Based on this criterion, we numerically demonstrate a body-center-cubic structure that supports wide-angle self-collimation and is directly compatible with the recently developed holographic fabrication technique. We further show that both bends and beam splitters can be intro...

Laboratory experiments demonstrate high-speed plasma flows from both footpoints of arched magnetic flux tubes, resulting in bulk plasma transport into the flux tube and persistent axial collimation even as the flux tube lengthens and kinks. The measured flows are in agreement with the predictions of hoop force and collimation models involving fundamental MHD forces. These forces are expected to...

We have studied laser collimation of a chromium atomic beam using a transverse polarization gradient cooling scheme. We present detailed measurements of the angular distribution of atoms on the beam axis, over a broad range of laser intensities and detunings including those which produce significant excitation, and observe collimation angles as small as 0.16 ± 0.01 mrad (50% quantile). We compa...