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Measurement of gas bremsstrahlung from the insertion device beamlines of the advanced photon source

Description: High energy electron storage rings generate energetic bremsstrahlung photons through radiative interaction of the electrons (or positrons) with the residual gas molecules inside the storage ring. The resulting radiation exits at an average emittance angle of (m{sub 0}c{sub 2}/E) radian with respect to the electron beam path, where m{sub 0}c{sup 2} is the rest mass of E the electron and E its kinetic energy. Thus, at straight sections of the storage rings, moving electrons will produce a narrow and intense monodirectional photon beam. At synchrotron radiation facilities, where beamlines are channeled out of the storage ring, a continuous gas bremsstrahlung spectrum, with a maximum energy of the electron beam, will be present. There are a number of compelling reasons that a measurement of the bremsstrahlung characteristics be conducted at the Advanced Photon Source (APS) storage ring. Although the number of residual gas molecules present in the storage ring at typical nTorr vacuum is low, because of the long straight paths of the electrons in the storage ring at APS, significant production of bremsstrahlung will be produced. This may pose a radiation hazard. It is then imperative that personnel be shielded from dose rates due to this radiation. There are not many measurements available for gas bremsstrahlung, especially for higher electron beam energies. The quantitative estimates of gas bremsstrahlung from storage rings as evaluated by Monte Carlo codes also have several uncertainties. They are in general calculated for air at atmospheric pressure, the results of which are then extrapolated to typical storage ring vacuum values (of the order of 10{sup -9} Torr). Realistically, the actual pressure profile can vary inside the narrow vacuum chamber. Also, the actual chemical composition of the residual gas inside the storage ring is generally different from that of air.
Date: March 1, 1997
Creator: Pisharody, M.; Job, P.K. & Magill, S.
Partner: UNT Libraries Government Documents Department

Intelligent Detector Design

Description: At a future e+e- linear collider, precision measurements of jets will be required in order to understand physics at and beyond the electroweak scale. Calorimetry will be used with other detectors in an optimal way to reconstruct particle 4-vectors with unprecedented precision. This Particle Flow Algorithm (PFA) approach is seen as the best way to achieve particle mass resolutions from dijet measurements in the range of {approx} 30%/{radical}E, resulting in innovative methods for choosing the calorimeter technology and optimizing the detector design.
Date: February 13, 2007
Creator: Graf, N.; Cassell, R.; Johnson, T.; McCormick, J.; /SLAC; Magill, S. et al.
Partner: UNT Libraries Government Documents Department

Argonne Plasma Engineering Experiment (APEX) Tokamak

Description: The Argonne Plasma Engineering Experiment (APEX) Tokamak was designed to provide hot plasmas for reactor-relevant experiments with rf heating (current drive) and plasma wall experiments, principally in-situ low-Z wall coating and maintenance. The device, sized to produce energetic plasmas at minimum cost, is small (R = 51 cm, r = 15 cm) but capable of high currents (100 kA) and long pulse durations (100 ms). A design using an iron central core with no return legs, pure tension tapewound toroidal field coils, digital radial position control, and UHV vacuum technology was used. Diagnostics include monochrometers, x-ray detectors, and a microwave interferometer and radiometer for density and temperature measurements. Stable 100 ms shots were produced with electron temperatures in the range 500 to 1000 eV. Initial results included studies of thermal desorption and recoating of wall materials.
Date: March 1, 1981
Creator: Norem, J.H.; Balka, L.J.; Kulovitz, E.E.; Magill, S.R.; McGhee, D.G.; Moretti, A. et al.
Partner: UNT Libraries Government Documents Department

Snowmass 2001 : jet energy flow project.

Description: Conventional cone jet algorithms arose from heuristic considerations of LO hard scattering coupled to independent showering. These algorithms implicitly assume that the final states of individual events can be mapped onto a unique set of jets that are in turn associated with a unique set of underlying hard scattering partons. Thus each final state hadron is assigned to a unique underlying parton. The Jet Energy Flow (JEF) analysis described here does not make such assumptions. The final states of individual events are instead described in terms of flow distributions of hadronic energy. Quantities of physical interest are constructed from the energy flow distribution summed over all events. The resulting analysis is less sensitive to higher order perturbative corrections and the impact of showering and hadronization than the standard cone algorithms.
Date: March 25, 2002
Creator: Berger, C. F.; L., Berger. E.; Bhat, P. C.; Butterworth, J. M.; Ellis, S. D.; Flaugher, B. et al.
Partner: UNT Libraries Government Documents Department

High Energy Physics division semiannual report of research activities, January 1, 1998--June 30, 1998.

Description: This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of January 1, 1998 through June 30, 1998. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of Division publications and colloquia are included.
Date: March 9, 1999
Creator: Ayres, D. S.; Berger, E. L.; Blair, R.; Bodwin, G. T.; Drake, G.; Goodman, M. C. et al.
Partner: UNT Libraries Government Documents Department

High Energy Physics Division semiannual report of research activities, January 1, 2004 - June 30, 2004.

Description: This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of January 1 through June 30, 2004. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of Division publications and colloquia are included.
Date: February 21, 2005
Creator: Spinka, H. M.; Nodulman, L. J.; Goodman, M. C.; Repond, J.; Ayres, D. S.; Proudfoot, J. et al.
Partner: UNT Libraries Government Documents Department

Summary : working group on QCD and strong interactions.

Description: In this summary of the considerations of the QCD working group at Snowmass 2001, the roles of quantum chromodynamics in the Standard Model and in the search for new physics are reviewed, with emphasis on frontier areas in the field. The authors discuss the importance of, and prospects for, precision QCD in perturbative and lattice calculations. They describe new ideas in the analysis of parton distribution functions and jet structure, and review progress in small-x and in polarization experiments.
Date: February 4, 2002
Creator: Berger, E. L.; Magill, S. R.; Sarcevic, I.; Jalilian-Marian, J.; Kilgore, W. B.; Kulesza, A. et al.
Partner: UNT Libraries Government Documents Department

High Energy Physics Division semiannual report of research activities : July 1, 2004 - December 31, 2004.

Description: This report describes the research conducted in the High Energy Physics Division of Argonne National Laboratory during the period of July 1 through December 31, 2004. Topics covered here include experimental and theoretical particle physics, advanced accelerator physics, detector development, and experimental facilities research. Lists of Division publications and colloquia are included.
Date: June 3, 2005
Creator: Nodulman, L.; Repond, J.; Ayres, D. S.; Proudfoot, J.; Stanek, R.; Schlereth, J. et al.
Partner: UNT Libraries Government Documents Department