We present the first calculation of a fully-unintegrated parton distribution (beam function) at next-to-next-to-leading order (NNLO). We obtain the fully-differential beam function for quark-initiated processes by matching it onto standard parton distribution functions (PDFs) at two loops. The fully-differential beam function is a universal ingredient in resummed predictions of observables prob...

A genetic algorithm has been used to optimize the selection of beam weights for external beam three-dimensional conformal radiotherapy treatment planning. A fitness function is defined, which includes a difference function to achieve a least-square fit to doses at preselected points in a planning target volume, and a penalty item to constrain the maximum allowable doses delivered to critical or...

We analyze the effects of the detector response time on bolometric measurements of the anisotropy of the cosmic microwave background (CMB). We quantify the effect in terms of a single dimensionless parameter L defined as the ratio between the time the beam sweeps its own size and the bolometer response time. As L decreases below ∼ 2.5 the point source response of the experiment becomes elongate...

Recently, several exact cone-beam reconstruction algorithms, such as the generalized filtered-backprojection (FBP) and backprojection-filtration (BPF) methods, have been developed to solve the long object problem. Although the well-known 3D Shepp-Logan phantom (SLP) is often used to validate these algorithms, it is deficient due to the discontinuity of the SLP. In this paper, we first construct...

This paper uses a PSOPC model based non-destructive damage identification procedure using frequency and modal data. The objective function formulation for the minimization problem is based on the frequency changes. The method is demonstrated by using a cantilever beam, four-bay plane truss and two-bay two-story plane frame with different scenarios. In this study, the modal data are provided nume...

We investigate laser ablation of crystalline silicon induced by a femtosecond optical vortex beam, addressing how beam properties can be obtained by analyzing the ablation crater. The morphology of the surface structures formed in the annular crater surface allows direct visualization of the beam polarization, while analysis of the crater size provides beam spot parameters. We also determine th...

The parallel electron distribution function has been measured on an electron beam from a magnetron injection gun (MIG) using an E 11 B energy analyzer. The magnetic field, beam voltage and beam current were scaled down from normal operating parameters. The perpendicular velocity spread, inferred under the assumption that the electrons are mono-energetic, is relatively constant for electron velo...

A non destructive low intensity ion beam profile monitor has been designed and tested. The system is based on a MCP that detects the residual gas ionization produced by the ion beam. The detector is coupled to a phosphorous screen for the readout of the vertical and horizontal density profiles. Experimental results have shown that the system is able to detect beam intensities as low as 10 pps w...

Current thinking about the Next Linear Collider (NLC) places a great deal of importance on magnetic beam compression. However, theoretical work has predicted that a large emittance growth may occur during magnetic compression due to coherent synchrotron radiation and the non-inertial space-charge force[1]. Applications such as the NLC cannot tolerate such beam degradation. To verify this predic...

The authors theoretically and numerically investigate the beam propagation near the supercollimation frequency s 0 in a photonic crystal made of nonlinear material. Since the value and sign of the equal-frequency-contour curvature which dominates the beam behaviors can be nonlinearly tuned near s , a kind of nonlinear effect is generated. The envelope equation with unique form is also obtained....