180 research outputs found
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The nonlinear CWFA (Cherenkov Wakefield Accelerator)
No full textThe possible use of nonlinear media to enhance the performance of the Cherenkov Wakefield Accelerator (CWFA) is considered. Numerical experiments have been performed using a new wakefield code which demonstrate larger gradients and transformer ratios in the nonlinear CWFA than are obtained in the linear case. 7 refs., 3 figs
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Wakefield calculations on parallel computers
No full textThe use of parallelism in the solution of wakefield problems is illustrated for two different computer architectures (SIMD and MIMD). Results are given for finite difference codes which have been implemented on a Connection Machine and an Alliant FX/8 and which are used to compute wakefields in dielectric loaded structures. Benchmarks on code performance are presented for both cases. 4 refs., 3 figs., 2 tabs
Data acquisition, control, and analysis for the Argonne Advanced Accelerator Test Facility (AATF)
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Data acquisition, control, and analysis for the Argonne Advanced Accelerator Test Facility (AATF)
No full textThe AATF has been used to study wakefield acceleration and focusing in plasmas and rf structures. A PC-based system is described which incorporates the functions of beamline control and acquisition, storage, and preliminary analysis of video images from luminescent screen beam diagnostics. General features of the offline analysis of wakefield data are also discussed. 4 refs., 3 figs
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Modeling coherent cherenkov radio emissions from high energy electromagnetic showers.
No full textA technique currently under study for the detection of ultrahigh energy cosmic ray neutrinos involves the measurement of radio emissions from the electromagnetic shower generated by the neutrino in a large volume of naturally occurring dielectric such as the Antarctic ice cap or salt domes. The formation of an electron excess in the shower leads to the emission of coherent Cherenkov radiation, an effect similar to the generation of wakefields in dielectric loaded structures. We have used the finite difference time domain (FDTD) wakefield code ARRAKIS to model coherent Cherenkov radiation fields from high energy showers; we present as an example calculations of expected signals in a proof of principle experiment proposed for the Fermilab Main Injector
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Results from an iron-proportional tube calorimeter prototype.
No full textWe have studied the energy resolution of a prototype gas tracking calorimeter in a test beam at Fermilab as part of the detector development program for the MINOS long baseline neutrino oscillation experiment. The calorimeter consisted of 25 layers of 1.5 inch thick steel plates interleaved with planes of aluminum proportional tubes. The tube cells are square, with 0.9 cm edges and open tops. Cathode strips were used for read out transverse to the wire cells. The tubes operated with a nonflammable gas mixture of 88% CO{sub 2}, 9.5% isobutane and 2.5% argon which gave an operating range of >500 V (limited by the electronics). We read out the wire signals on the tubes and in some configurations the cathode stripe as well. We studied positrons, pions and muons over a momentum range of 2.5-30 GeV/c and achieved energy resolutions of about 40%/{radical}E for EM and 71%/{radical}E for hadronic showers
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Calculation of higher order modes in the RHIC 27 MHz rf cavity
No full textThe URMEL code was used to calculate the frequencies, quality factors, and shunt impedances of the lowest modes of the proposed RHIC accelerating cavity. These values can be used as input for the calculation of the longitudinal and transverse coupled-bunch instabilities. The cavity dimensions were taken from the RHIC conceptual design report
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Accelerator based coal positron beams
No full textCold positron beams produced using solid state moderators have been used profitably for condensed matter and positronium research. The low emittance and energy spread of these beams make the technique attractive as a potential positron source for future linear colliders, reducing or eliminating the need for damping rings. However, the intensities attained so far fall short of the requirements of a high energy linear collider. (approx.10/sup 11/ positrons/pulse at 10 kHz was taken as the positron flux necessary for a linear collider-B anti B factory). This report briefly reviews the state of the art in accelerator produced coal positron beams and indicates some areas in which yields might be improved. The discussion here is limited to electroproduced positrons
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