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A Theoretical Study of the Two-Dimensional Point Focusing by Two Multilayer Laue Lenses.

Description: Hard x-ray point focusing by two crossed multilayer Laue lenses is studied using a full-wave modeling approach. This study shows that for a small numerical aperture, the two consecutive diffraction processes can be decoupled into two independent ones in respective directions. Using this theoretical tool, we investigated adverse effects of various misalignments on the 2D focus profile and discussed the tolerance to them. We also derived simple expressions that described the required alignment ac… more
Date: August 10, 2008
Creator: Yan,H.; Maser, J.; Kang, H.C.; Macrader, A. & Stephenson, B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

14-MeV Neutron Generator Used as a Thermal Neutron Source

Description: One of the most important applications of the general purpose Monte Carlo N-Particle (MCNPS and MCNPX) codes is neutron shielding design. We employed this method to simulate the shield of a 14-MeV neutron generator used as a thermal neutron source providing an external thermal neutron beam for testing large area neutron detectors developed for diffraction studies in biology and also useful for national security applications. Nuclear reactors have been the main sources of neutrons used for scien… more
Date: August 10, 2008
Creator: Dioszegi, I.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Fast fall-time ion beam in neutron generators

Description: Ion beam with a fast fall time is useful in building neutron generators for the application of detecting hidden, gamma-shielded SNM using differential die-away (DDA) technique. Typically a fall time of less than 1 {micro}s can't be achieved by just turning off the power to the ion source due to the slow decay of plasma density (partly determined by the fall time of the RF power in the circuit). In this paper, we discuss the method of using an array of mini-apertures (instead of one large apertu… more
Date: August 10, 2008
Creator: Ji, Q.; Kwan, J.; Regis, M.; Wu, Y.; Wilde, S.B. & Wallig, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Experimental Background Due to Particle Induced Gas Desorption in RHIC

Description: Beam-gas collision created experimental background, i.e., singles, has affected heavy ion and polarized proton operations in Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The gas molecules in interaction region are mainly caused by the electron induced gas desorption. and the electrons are produced from the beam induced electron multipacting, or called electron cloud. The background has a dependence on the usual electron cloud related parameters, such as the bunch intensity… more
Date: August 10, 2008
Creator: Zhang, S. Y. & Trbojevic, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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