552 Matching Results

Search Results

Advanced search parameters have been applied.

Upgrade of the Proton West secondary beamline

Description: As originally designed and operated, protons entering PW6 were steered by a series of EPB dipoles into a single interaction length beryllium target, some 43 feet from the enclosure wall. Ensuing secondary beams, either p{sup +}/{pi}{sup +} or p{sup -}/{pi}{sup -}, were collected by a string of quadrupoles following the target, steered westward, away from the Proton Center line, through PW6 and PW7, and ultimately focussed on experiment production targets located within the large PW8 hall. Around the Spring of 1988 it was decided to upgrade the existing Proton West secondary beamline to allow for transport of a primary proton beam, anticipated to be either 800 or 900 GeV/c, through PW8. This upgrade project, which is now nearing completion, was largely motivated by the then recent approval of E-771, a hadronic beauty production experiment located in PW8. E-771 represents the third in a series of experiments for the large-acceptance dimuon spectrometer presently located at the end of the Proton West beamline. This Technical Memo is a summary of the upgrade --- an explanation of the underlying strategy and a documentation of the final locations of the secondary beamline elements. 6 refs., 2 figs., 2 tabs.
Date: October 10, 1989
Creator: Spiegel, L.
Partner: UNT Libraries Government Documents Department

NCI dichromatic beam tests

Description: The initial tests of the NCI dichromatic train showed that the momentum bite was within 2% of design. Though the data is by no means definitive, the particle fractions measured at 800 GeV are reasonably close to those predicted from 400 GeV data. A first look at the angular divergence of the beam showed it to be within 10% of design in the horizontal plane and about 35% greater than design in the vertical plane. Several problems were discovered which will be corrected before the next run.
Date: March 1, 1986
Creator: Stutte, L.
Partner: UNT Libraries Government Documents Department

An 805 MHz disk and washer accelerating structure with coaxial coupler for the Fermilab upgrade

Description: The Disk and Washer (DAW) structure with four bi-periodic tees to support the washers has been studied at Fermilab for the Linac Upgrade by constructing two, 805 MHz, one-meter sections joined by a coaxial coupler. The coupler provides an rf drive port, an adjustable tuner, a vacuum port, and an enclosure for the installation of beam focussing and monitoring devices. This configuration is suitable for a high beta proton linear accelerator. The bi-periodic tee supports in the DAW structure suppress the TM{sub 11} mode at the operating frequency which has been a problem with previous designs. Frequency-mode spectra have been calculated and measured as well as the quantities Q, R/Q, and ZT{sup 2}. The structure has been evacuated and operated at high power levels and high accelerating fields. 5 refs., 4 figs., 2 tabs.
Date: September 1, 1989
Creator: Young, D.E.; Moretti, A.; Lee, G.; Mills, F.E.; Zhou, P. (Fermi National Accelerator Lab., Batavia, IL (USA)); Swenson, D.A. et al.
Partner: UNT Libraries Government Documents Department

Possibilities of polarized protons in Sp anti p S and other high energy hadron colliders

Description: The requirements for collisions with polarized protons in hadron colliders above 200 GeV are listed and briefly discussed. Particular attention is given to the use of the ''Siberan snake'' to eliminate depolarizing resonances, which occur when the spin precession frequency equals a frequency contained in the spectrum of the field seen by the beam. The Siberian snake is a device which makes the spin precession frequency essentially constant by using spin rotators, which precess the spin by 180/sup 0/ about either the longitudinal or transverse horizontal axis. It is concluded that operation with polarized protons should be possible at all the high energy hadron colliders. (LEW)
Date: January 1, 1984
Creator: Courant, E.D.
Partner: UNT Libraries Government Documents Department

Intrinsic and resonance space charge limits

Description: The space charge limit in circular proton accelerators has been studied using a simulation program described below. Results from the simulation study indicate a different model for the space charge limit than the often presented models which emphasize resonances due to magnetic field errors. This simulation study suggests that the intrinsic space charge limit plays an important role. The intrinsic space charge limit is the space charge limit, in the absence of magnetic field errors, and is due to the forces generated by the beam itself. In studies of three operating accelerators, which include the AGS, the PS Booster and the Fermilab booster, it was found that the computed intrinsic space charge limit was fairly close to the experimentally observed space charge limit. This result plus studies of the effects of resonances due to magnetic field errors suggest that the intrinsic space charge limit provides an upper bound for the space charge limit which is not far from what is actually achieved by operating accelerators. The resonances present due to magnetic field errors, if strong enough, can prevent the accelerator from achieving the intrinsic space charge limit. However, the effects of these resonances were found to be appreciable only when the beam intensity gets close to the intrinsic space charge limit. Well below the intrinsic space charge limit, there is little beam growth due to magnetic field error driven resonances, and the space charge forces tend to stabilize these resonances. 4 refs., 5 figs.
Date: January 1, 1989
Creator: Parzen, G.
Partner: UNT Libraries Government Documents Department

Polarization effects. Volume 2

Description: The use of polarized proton beams in ISABELLE is important for several general reasons: (1) With a single longitudinally polarized proton beam, effects involving parity violation can be identified and hence processes involving weak interactions can be separated from those involving strong and electromagnetic interactions. (2) Spin effects are important in the strong interactions and can be useful for testing QCD. The technique for obtaining polarized proton beams in ISABELLE appears promising, particularly in view of the present development of a polarized proton beam for the AGS. Projections for the luminosity in ISABELLE for collisions of polarized protons - one or both beams polarized with longitudinal or transverse polarization - range from 1/100 to 1 times the luminosity for unpolarized protons.
Date: January 1, 1981
Creator: Courant, E.
Partner: UNT Libraries Government Documents Department

Simple computer model for the nonlinear beam--beam interaction in ISABELLE

Description: The beam--beam interaction for two counter-rotating continuous proton beams crossing at an angle can be simulated by a 1-dimensional nonlinear force. The model is applicable to ISABELLE as well as to the ISR. Since the interaction length is short compared with the length of the beam orbit, the interaction region is taken to be a point. The problem is then treated as a mapping with the remainder of the system taken to be a rotation of phase given by the betatron tune of the storage ring. The evolution of the mean square amplitude of a given distribution of particles is shown for different beam--beam strengths. The effect of round-off error with resulting loss of accuracy for particle trajectories is discussed. 3 figures.
Date: March 1, 1979
Creator: Herrera, J.C.; Month, M. & Peierls, R.F.
Partner: UNT Libraries Government Documents Department

A pinger system for the Los Alamos Proton Storage Ring

Description: Developers at the Proton Storage Ring have long desired a modulator and electrode combination capable of kicking the 800-MeV proton beam enough to conduct tune measurements with full intensity beams. At present this has been accomplished by reducing the voltage on one extraction kicker modulator and turning the other off. This method requires that all of the accumulated beam be lost on the walls of the vacuum chamber. In addition to tune measurements a more recent desire is to sweep out beam that may have leaked into the area between bunches. A four-meter electrode has been designed and constructed for the purpose. The design is flexible in that the electrode may be split in the center and rotated in order to provide vertical and horizontal electrodes each 2 meters long. In addition two solid-state pulse modulators that can provide 10kV in burst mode at up to 700 KHz have been purchased. This hardware and its intended use are described. 3 refs., 2 figs., 1 tab.
Date: January 1, 1991
Creator: Hardek, T.W. & Thiessen, H.A.
Partner: UNT Libraries Government Documents Department

Design for a second-generation proton storage ring at LAMPF

Description: A conceptual design is presented for a second-generation proton storage ring complex at LAMPF. The facility would consist of two stacked racetrack-shaped machines. These machines would deliver a 1.2-mA beam of 1.6-GeV protons at 48 Hz. The pulse length would be 1.75 ..mu..sec which represents a time compression of 570. 3 refs., 4 figs., 1 tab.
Date: January 1, 1989
Creator: Colton, E.P.
Partner: UNT Libraries Government Documents Department

T type collimator

Description: The Research Division has developed a pin-hole collimator capable of attenuating the 800 GeV proton beam by a factor of ten to one hundred. A bid package has been let for the first prototype and has been sent out. The other four collimators will be ordered in the spring of 1989. 3 refs., 2 figs., 3 tabs.
Date: January 1, 1989
Creator: LaVallie, E.; Smith, G.; Sorenson, D. & Volk, J.
Partner: UNT Libraries Government Documents Department

Run permit software for the proton storage ring

Description: The Run Permit system is intended to protect equipment from radiation effects caused by having beam enabled when required equipment is not operational. This system will not allow beam unless certain devices are ready and will drop beam if any of these devices become inoperative. A system to provide such protection might be implemented in hardware. However, because the several operating modes of the Proton Storage Ring/Weapons Neutron Research facility require certain devices to be in different states (depending on mode), a dynamic configuration capability is needed, that is, a software solution is more feasible.
Date: January 1, 1985
Creator: Bair, S.S.
Partner: UNT Libraries Government Documents Department

High Intensity Hadron Accelerators

Description: In this paper we give an introductory discussion of high intensity hadron accelerators with special emphasis on the high intensity feature. The topics selected for this discussion are: Types of acclerator - The principal actions of an accelerator are to confine and to accelerate a particle beam. Focusing - This is a discussion of the confinement of single particles. Intensity limitations - These are related to confinement of intense beams of particles. Power economics - Considerations related to acceleration of intense beams of particles. Heavy ion kinematics - The adaptation of accelerators to accelerate all types of heavy ions.
Date: June 1984
Creator: Teng, L. C.
Partner: UNT Libraries Government Documents Department

Simulation of proton RF capture in the AGS Booster

Description: RF capture of the proton beam in the AGS Booster has been simulated with the longitudinal phase-space tracking code ESME. Results show that a capture in excess of 95% can be achieved with multiturn injection of a chopped beam.
Date: January 1, 1988
Creator: Khiari, F.Z.; Luccio, A.U. & Weng, W.T.
Partner: UNT Libraries Government Documents Department

Collective effects in short bunches: Summary of the Working Group on Proton Bunches

Description: This report discusses the following topics on proton beam bunching: space charge, a collective but incoherent effect; a very short proton bunch; long proton bunches; transition energy crossing; intrabeam scattering; vacuum related effects; and the issue of mode-coupling for proton bunches. (LSP)
Date: October 10, 1990
Creator: Ruggiero, A.G.
Partner: UNT Libraries Government Documents Department

Direction-dependent stopping power and beam deflection in anisotropic solids

Description: Directional effects on the motion of swift ions in anisotropic media are studied. The stopping power is a function of the direction of the velocity relative to the principle axes of the medium, and there is a nonzero lateral force on the ion tending to bend its trajectory. These effects arise from the anisotropy of the dielectric response, and are distinct from channeling. Simple expressions are derived for the stopping power and lateral force in the nonrelativistic high-velocity limit, and calculations are performed for crystalline graphite. 6 refs., 7 figs.
Date: January 1, 1989
Creator: Crawford, O.H.
Partner: UNT Libraries Government Documents Department

First order tune shift calculations for transverse betatron dynamics

Description: An effective Hamiltonian, with non-linear magnetic multipole terms and momentum dispersion contributions, is used to obtain the first order tune-shift results for transverse betatron motion for protons in the Superconducting Super Collider (SSC). This Hamiltonian is represented in terms of action angle variables, and analytical results are obtained using symbolic algebra methods. Mathematical derivations of the transverse multipole expansion and of the transverse betatron equations, using an invariant action and curvilinear coordinates, are given in the appendices. Numerical and graphical tune-space results are given that illustrate the dependence of tune-shifts on injection amplitude and momentum spread. 10 refs., 7 figs.
Date: September 1, 1991
Creator: Garavaglia, T.
Partner: UNT Libraries Government Documents Department

Measurement of ultracold neutrons produced by using Doppler-shifted Bragg reflection at a pulsed-neutron source

Description: Ultracold neutrons (UCN) have been produced at the Argonne pulsed-neutron source by the Doppler shift of 400-m/s neutrons Bragg reflected from a moving crystal. The peak density of UCN produced at the crystal exceeds 0.1 n/cm/sup 3/.
Date: January 1, 1979
Creator: Brun, T.O.; Carpenter, J.M.; Krohn, V.E.; Ringo, G.R.; Cronin, J.W.; Dombeck, T.W. et al.
Partner: UNT Libraries Government Documents Department

Commissioning the polarized beam in the AGS

Description: After the successful operation of a high energy polarized proton beam at the Argonne Laboratory Zero Gradient Synchrotron (ZGS) was terminated, plans were made to commission such a beam at the Brookhaven National Laboratory Alternating Gradient Synchrotron (AGS). On February 23, 1984, 2 ..mu..A of polarized H/sup -/ was accelerated through the Linac to 200 MeV with a polarization of about 65%. 1 ..mu..A was injected into the AGS and acceleration attempts began. Several relatively short runs were then made during the next three months. Dedicated commissioning began in early June, and on June 26 the AGS polarized beam reached 13.8 GeV/c to exceed the previous ZGS peak momentum of 12.75 GeV/c. Commissioning continued to the point where 10/sup 10/ polarized protons were accelerated to 16.5 GeV/c with 40% polarization. Then, two experiments had a short polarized proton run. We plan to continue commissioning efforts in the fall of this year to reach higher energy, higher intensity, and higher polarization levels. We present a brief description of the facility and of the methods used for preserving the polarization of the accelerating beam.
Date: January 1, 1985
Creator: Ratner, L.G.; Brown, H.; Chiang, I.H.; Courant, E.; Gardner, C.; Lazarus, D. et al.
Partner: UNT Libraries Government Documents Department

Informal workshop on intense polarized ion sources: a summary

Description: An Informal Workshop on Intense Polarized Ion Sources was held on March 6, 1980, at the O'Hare Hilton Hotel, Chicago, Illinois. The purpose of the Workshop was to discuss problems in developing higher-intensity polarized proton sources, particularly the optically-pumped source recently proposed by L.W. Anderson of the University of Wisconsin. A summary of the discussions is reported.
Date: January 1, 1980
Creator: Schultz, P.F. (ed.)
Partner: UNT Libraries Government Documents Department

Beam-beam interactions for bunched and unbunched beams

Description: The beam-beam interaction is analyzed in terms of Chirikov's stochasticity model. Stochastic blow-up occurs when the density of resonance regions in phase space becomes large, and Arnold diffusion is assumed to depend on the density parameter below the stochastic threshold. The relation between the density parameter and the tune shift epsilon is affected by bunching of the beam and also by variations in the strengths of several interaction regions and by beam misalignment. It is seen that bunching can reduce the tolerable epsilon by as much as an order of magnitude in proton storage rings.
Date: January 1, 1980
Creator: Courant, E D
Partner: UNT Libraries Government Documents Department