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in subjects: "Linear Colliders"

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Prospects for physics at e/sup +/e/sup -/ linear colliders

The present thinking on high-energy e/sup /plus//e/sup /minus// linear colliders is reviewed, stressing those points that have consequences for detector design and physics analyses. Detector requirements are discussed. Experimental aspects of the physics that can be done at these colliders are discussed: first the general physics environment, then a standard process, W/sup /plus// W/sup /minus// detection, and finally four examples of the discovery potential of these colliders /emdash/ heavy qu… more

Date: March 1, 1988

Creator: Feldman, G. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Physics at TeV e sup + e sup minus linear colliders

A survey is presented of the physics opportunities at TeV e{sup +}e{sup {minus}} linear colliders. Examples are given of physics that might emerge in e{sup +}e{sup {minus}} collisions and in {gamma}{gamma} collisions using the back-scattered laser technique, including {gamma}{gamma} {yields} ZZ scattering as a probe of ultraheavy quanta. The second portion of the talk focuses on physics that must emerge at or below the TeV scale--the mechanism of electroweak symmetry breaking. In particular a v… more

Date: January 1, 1992

Creator: Chanowitz, Michael S.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electron-positron physics at 1 TeV

We discuss the motivation for TeV e/sup +/ e/sup )minus/) linear colliders, some aspects of their design, and the experimental consequences that follow from the design. After a brief discussion of the general physics environment, we consider the discovery potential of these colliders by examining three sample processes: the detection of new heavy leptons, standard Higgs bosons, and charged Higgs bosons. 13 refs., 22 figs., 5 tabs.

Date: March 1, 1988

Creator: Feldman, G. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Experimental and theoretical investigation of high gradient acceleration

This report contains a technical progress summary of the research conducted under the auspices of DOE Grant No. DE-FG0291ER-40648. Experimental and Theoretical Investigations of High Gradient Acceleration.'' This grant supports three research tasks: Task A consists of the design and fabrication of a 17GHz of photocathode gun, Task B supports the testing of high gradient acceleration using a 33GHz structure, and Task C comprises theoretical investigations, both in support of the experimental tas… more

Date: February 1, 1992

Creator: Bekefi, G.; Chen, C.; Chen, S.; Danly, B.; Temkin, R.J. & Wurtele, J.S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Physics issues for the next linear collider

This article surveys the physics issues to be studied at future e{sup +}e{sup {minus}} colliders, especially in the energy region below 500 GeV. Particular emphasis is given to standard model studies -- precision measurements of the dynamical properties of W bosons and top quarks -- as well as the search for evidence of the Higgs sector.

Date: April 1, 1992

Creator: Peskin, M.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Experimental W boson physics at future e sup + e sup minus linear colliders

The study of triple and quartic gauge boson vertices will be the centerpiece of experimental W boson physics at the next generation e{sup +}e{sup {minus}} linear collider. We examine the sensitivity of a {radical}{bar s} = 500 GeV e{sup +}e{sup {minus}} linear collider to anomalous structure in the W{sup +}W{sup {minus}} {gamma} and W{sup +}W{sup {minus}}Z vertices. These vertices are tested by observing the reactions e{sup {minus}} {gamma} {yields} {nu}W{sup {minus}}, {gamma}{gamma} {yields} W… more

Date: April 1, 1992

Creator: Barklow, T.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Beam dynamics and rf evolution in a multistage klystron-like free- electron laser

Current understandings of beam dynamics and RF evolution in a klystron-like free-electron laser are present. Phase sensitiveness to injection jitters estimated by existing two theories is discussed. BBU suppression due to linear detuning is proposed as an alternative of ever proposed techniques. 13 refs., 2 figs., 1 tab.

Date: January 1, 1991

Creator: Ohnuma, S. (Houston Univ., TX (United States). Inst. for Beam Particle Dynamics) & Takayama, K. (Houston Univ., TX (United States). Inst. for Beam Particle Dynamics Texas Accelerator Center, The Woodlands, TX (United States))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Towards the next linear collider

This report discusses design choices for the next generation linear colliders. (LSP)

Date: September 1, 1991

Creator: Irwin, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Investigation of a constant gradient structure with constant iris size

Travelling wave accelerators can be built either with constant impedance or constant gradient structures. Whereas for the constant impedance case the geometry of the cells does not change, the iris size in a constant gradient structure is decreased from cell to cell in order to slow down the power flow of the incoming rf pulse by reducing the group velocity in order to achieve P'(z) = const. Changing the phase advance per cell for the accelerating wave from the beginning towards the end of the … more

Date: July 1, 1991

Creator: Holtkamp, N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The coupled dipole modes of the NLC accelerator structure

The proposed accelerator cavity of the Next Linear Collider (NLC) is a disk-loaded structure composed of 200 cells, operating at 11.42 GHz. The proposed mode of operation is to accelerate bunches in trains of 10, with a bunch spacing of 42 cm. One problem is that one bunch in a train can excite transverse wakefields in the accelerator cavity which, in turn, can deflect following bunches and result in emittance growth. A method of curing this problem is to detune the transverse modes of the cavi… more

Date: March 1, 1992

Creator: Bane, K.L.F.; Gluckstern, R. & Holtkamp, N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A three-gap klystron output cavity at X-band

A high-power X-band klystron employing a double-gap output cavity has been operating at SLAC. Multi-gap output circuits have lower surface gradients at the interaction gaps than single-gap ones but are prone to self-oscillate due to negative loading and trapped higher-order modes. In the double-gap circuit design, considerable attention had been directed to deal with these stability problems. The performance of the present tube appears to be limited by gap breakdown and beam interception partic… more

Date: March 1, 1992

Creator: Ko, K.; Lee, T.G.; Tonegawa, S. (Stanford Linear Accelerator Center, Menlo Park, CA (United States)) & Kroll, N. (Stanford Linear Accelerator Center, Menlo Park, CA (United States) California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics)

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Alternative positron-target design for electron-positron colliders

Current electron-positron linear colliders are limited in luminosity by the number of positrons which can be generated from targets presently used. This paper examines the possibility of using an alternate wire-target geometry for the production of positrons via an electron-induced electromagnetic cascade shower. 39 refs., 38 figs., 5 tabs.

Date: April 1, 1991

Creator: Donahue, R. J. & Nelson, W. R.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Accelerator prospects for photon-photon physics

This paper provides an overview of the accelerators in the world where two-photon physics could be carried out in the future. The list includes facilities where two-photon physics is already an integral part of the scientific program but also mentions some other machines where initiating new programs may be possible.

Date: May 1, 1992

Creator: Hutton, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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New technology for linear colliders

The purpose of this contract is to develop and evaluate new technology for future e{sup +}e{sup {minus}} linac colliders. TeV linac colliders will require major improvements in the performance of microwave power tubes: >100 mW/m peak power, {approximately}20 GHz frequency, and high frequency. For the past three years we have been developing gigatron, a new design concept for microwave power tubes. It incorporates three key innovations: a gated field-emitter cathode which produces a fully modula… more

Date: August 1991

Creator: McIntyre, Peter M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Breakdown of QED vacuum and luminosity lifetime of a heavy ion collider

During beam crossing at a Relativistic Heavy Ion Collider the peripheral electromagnetic field between the fully stripped ions in colliding bunches is sufficiently intense to induce copious particle production. In this manuscript the production of free pair e{sup +},e{sup {minus}} leptons and bound-electron plus free e{sup +} particles are addressed in detail. In particular, both perturbative and non-perturbative approaches to these reactions are addressed. Capturing a produced electron into a … more

Date: January 1, 1991

Creator: Rhoades-Brown, M.J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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An immersed field cluster klystron

Future linear colliders have a need for high power, high frequency, and short-pulse radio frequency sources. The proposed ''cluster klystron'' should give over 1 GW of 12 GHz radio frequency power, can employ direct current or a long high-voltage pulse, but can be gated to give pulses down to a few tens of nanoseconds. The device consists of 42 parallel 100 A channels. Each channel is fed from an individual magnetron-type gun employing a common 50 kV mod-anode. The beams are accelerated to 400 … more

Date: August 1, 1989

Creator: Palmer, R. B.; Herrmannsfeldt, W. B. & Eppley, K. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Beam emittance and the effects of the rf, space charge and wake fields: Application to the ATF photoelectron beam

Laser driven photoelectron guns are of interest for use in new methods of accelerations, future development of Linear Colliders and new experiments such as Free Electron laser (IFEL). Such guns are potential source of low emittance-high current and short bunch length electron beams, where the emitted electrons are accelerated quickly to a relativistic energy by a strong rf, electric field in the cavity. We present a brief overview of the beam dynamic studies, e.g. emittance for the Brookhaven N… more

Date: January 1, 1991

Creator: Parsa, Z.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Misalignment study of NLC bunch compressor

Results of computer simulations of the misalignments in the 180{degree}-bend angle second-stage bunch compressor for the NLC are described. The aim of this study was to evaluate alignment and production error tolerances. Three versions of the second stage, differing in their minimum obtainable bunch length (44 {mu}, 60 {mu}, and 86 {mu}) were studied. Simulations included orbit correction produced by errors and misalignments of the compressor elements. The orbit correction itself was done withi… more

Date: May 1, 1991

Creator: Rogers, R.P. & Kheifets, S.A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A possible design for the NLC e sup + source

The Next Linear Collider (NLC) currently under investigation at SLAC requires a positron source with a flux of about 8.6 {times} 10{sup 13} particles per second, 14.4 times more than the SLC source. Based on the SLC experience, a source for NLC is proposed that can be realized with present accelerator technology. It consists of a 7 GeV S-band electron linac, a solid moving target, a 1.8 GeV L-band positron accelerator and a pre-damping ring with a large acceptance. The pre-damping ring performs… more

Date: February 1, 1992

Creator: Braun, H. (Paul Scherrer Inst. (PSI), Villigen (Switzerland)); Clendenin, J.; Eucklund, S.; Kulikov, A. (Stanford Linear Accelerator Center, Menlo Park, CA (United States)) & Pitthan, R. (European Organization for Nuclear Research, Geneva (Switzerland))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Review of pulsed rf power generation

I am going to talk about pulsed high-power rf generation for normal-conducting electron and positron linacs suitable for applications to high-energy physics in the Next Linear Collider, or NLC. The talk will cover some basic rf system design issues, klystrons and other microwave power sources, rf pulse-compression devices, and test facilities for system-integration studies.

Date: April 1, 1992

Creator: Lavine, T. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Future US scientific program

Central to planning for the future program of high energy physics in the US is the Superconducting Super Collider. While it is being built during roughly the next decade, the present HEP laboratories plan an extensive program of physics measurements. Upgrades and new facilities will allow a vigorous program. 3 figs.

Date: January 1, 1991

Creator: Price, L.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Numerical simulation of the SLAC X-100 klystron using RKTW2D

We have performed numerical simulations of the X-100 klystron being developed at Stanford Linear Accelerator Center. The X-100 is being developed as a possible source for the next generation of linear collider, and will be required to produce {approx}100 MW of power for a duration of {approx}800 ns. Our simulations were performed using the simulation programs RKTW1D and RKTW2D, developed at Lawrence Livermore National Laboratory. The codes were used to investigate the operation of the klystron … more

Date: May 1, 1991

Creator: Ryne, R.D. (Lawrence Livermore National Lab., CA (USA)) & Vlieks, A.E. (Stanford Linear Accelerator Center, Menlo Park, CA (USA))

Item Type: Article

Partner: UNT Libraries Government Documents Department

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The hunt for new gauge bosons: Present status and future prospects

We survey the present limits on and future searches for new gauge bosons via direct production at colliders as well as by indirect methods such as radiative corrections analyses and cosmological constraints on the number of neutrinos. 29 refs., 10 figs., 1 tab.

Date: September 1, 1991

Creator: Rizzo, T. G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Coherent pair creation from beam-beam interaction

It has recently been recognized that in future linear colliders, there is a finite probability that the beamstrahlung photons will turn into e{sup +}e{sup {minus}} pairs induced by the same beam-beam field, and this would potentially cause background problems. In this paper, we first review the probability of such a coherent pair creation process. It is seen that the constraint on the beamstrahlung parameter, {Upsilon}, is tight of these coherent pairs to be totally suppressed. We then point ou… more

Date: September 1, 1989

Creator: Chen, Pisin.

Item Type: Article

Partner: UNT Libraries Government Documents Department