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Fields and forces for rectangular beams in an AGS

Description: The direct space-charge fields and forces that are present in a proton beam which has a rectangular cross section and a uniform charge density are considered. The horizontal and vertical betatron tune shifts, corresponding to these forces, which occur within such a beam are calculated. In addition, a direct extension of this rectangular model produces analytical expressions for the tune changes characteristic of a beam profile which has symmetrical or unsymmetrical linear variations of charge density at the horizontal edges of the beam. (auth)
Date: June 26, 1975
Creator: Herrera, J.C.
Partner: UNT Libraries Government Documents Department

Tables of particle fluxes

Description: The formula of F. Paige for secondary particle fluxes expected at ISABELLE has for convenience been tabulated over a range of momenta. The data are presented as flux/sec in 1 cm sq. areas. areas at various x, y positions (x = y = 0 is the intersection point) in a plane perpendicular to one of the colliding beams and located 1 meter from their intersection. The 1 cm sq. areas are taken as planes perpendicular to a vector connecting the area to the intersection point. Relevant parameters for each table are listed at the top of the table.
Date: January 1, 1977
Creator: Willen, E.H.
Partner: UNT Libraries Government Documents Department

Reducing. beta. /sub x/ and X/sub p/ by the use of a split quadrupole lattice

Description: The ..beta../sub x/ function and the dispersion function X/sub p/ at the regular focusing quadrupole in the ISABELLE cell can be reduced by rearranging the quadrupoles and dipoles in the regular cell. In this arrangement, the focusing quadrupole is split in half and one or two of the dipoles in the cell are inserted between the two halves of the focusing quadrupole. This arrangement leads to a smaller beam size, and can sometimes lead to a smaller aperture requirement.
Date: September 1, 1977
Creator: Hahn, H & Parzen, G
Partner: UNT Libraries Government Documents Department

Position and profile of a multiampere proton beam

Description: The spacial profile of a bunched or unbunched proton beam may be found by using a highly collimated molecular beam of N/sub 2/. A certain fraction of the molecular N/sub 2/ will be ionized as it crosses the proton beam. By measuring the N/sub 2//sup +/ current as a function of theta the cross section of the beam is directly obtained. As an example, a 10 A proton beam of diameter 1 mm is considered.
Date: October 20, 1977
Creator: Edwards, D. Jr.
Partner: UNT Libraries Government Documents Department

Numerical filtering method for elimination of errors in bone mineral measurements caused by finite photon beam size

Description: A method is described for removing the effect of the finite beam size by deconvoluting the collimated beam profile from the observed transmission curve. The technique uses discrete Fourier transforms for the derivation of the restoring filter. In measurements performed on a circular bone phantom the restoration of the transmitted curve resulted in reduction of the errors in bone dimensions and linear bone mass. Results obtained from restoration of the transmission curve of a rat femur are presented.
Date: January 1, 1978
Creator: Vartsky, D.; Ellis, K.J.; Pearlstein, T.B. & Cohn, S.H.
Partner: UNT Libraries Government Documents Department

Beam profile monitor. [4 drawings (separate from report)]

Description: A system used to monitor secondary beam profiles at the LAMPF Linac for channel tune-up and diagnostics is described. The multiwire proportional chamber design is discussed, and descriptions and drawings of the gate card, the amplifier/multiplexer card, the output amplifier card, and the overall system are given. (PMA)
Date: May 1, 1978
Creator: Krausse, G.J. & Gram, P.A.M.
Partner: UNT Libraries Government Documents Department

Duopigatron ion source studies

Description: Ion source performance characteristics consisting of total ion current, ion energy distribution, mass distribution, and ion current density distribution were measured for several models of a duopigatron. Variations on the duopigatron design involved plasma expansion cup material and dimensions, secondary cathode material, and interelectrode spacings. Of the designs tested, the one with a copper and molybdenum secondary cathode and a mild steel plasma expansion cup proved to give the best results. The ion current density distribution was peaked at the center of the plasma expansion cup and fell off to 80 percent of the peak value at the cup wall for a cup 15.2 mm deep. A total ion current of 180 mA consisting of 60 to 70 percent atomic ions was produced with an arc current of 20 A and source pressure of 9.3 Pa. More shallow cups produced a larger beam current and a more sharply peaked ion current density distribution. Typical ion energy distributions were bell-shaped curves with a peak 10 to 20 V below anode potential and with ion energies extending 30 to 40 V on either side of the peak.
Date: July 1, 1978
Creator: Bacon, F.M.; Bickes, R.W. Jr. & O'Hagan, J.B.
Partner: UNT Libraries Government Documents Department

Beam tomography or ART in accelerator physics. [Current density profiles]

Description: Projections of charged particle beam current density have been used for many years as a measure of beam position and size. The conventional practice of obtaining only two projections, usually in the horizontal and vertical planes, puts a severe limit on the detail that can be recovered from the projections. A third projection provides sufficient improvement to justify the addition of a wire to the conventional wire scanner in certain cases. A group of programs using algebraic reconstruction techniques was written to reconstruct beam current density from beam projections obtained at three or more specific or arbitrary angles around the beam. A generalized program, which makes use of arbitrary 2 x 2 transfer matrices between projections, can be used to reconstruct transverse or longitudinal emittance from appropriate projections. Reconstruction examples of beam current density and transverse and longitudinal emittance using experimental data from the Clinton P. Anderson Meson Physics Facility (LAMPF) accelerator beam are given.
Date: November 1, 1978
Creator: Fraser, J.S.
Partner: UNT Libraries Government Documents Department

Laser-beam profiler and detector-surface scanner

Description: A portable, relatively inexpensive laser-beam profiler and detector-surface scanner has been developed to map the intensity profile of laser beams and the cross-sectional response of optical detectors within a wavelength range of 633 nm to 10.6 ..mu..m. Equipment diagrams, circuit schematics, and examples of detector-response maps and laser-beam profiles are provided. Intensity distribution is an important parameter in obtaining good laser welds, and a knowledge of the detector response is essential in determining the accuracy of laser power measurements.
Date: November 1, 1978
Creator: Foulk, L.R.
Partner: UNT Libraries Government Documents Department

Beam tomography in two and four dimensions. [100 MeV H/sup +/ beams and 750 keV H/sup -/ beams]

Description: The coming generations of high beam-power accelerators require new techniques to monitor the emittance and the shape of the beam; in particular, measurements that do not interfere with the beam itself are necessary. A new computational algorithm, MENT (Maximum ENTropy), will be presented that combines nondestructive profile measurements taken from a number of stations along the beam line with beam-dynamics calculations to compute a four-dimensional phase-space distribution. A version of MENT has been used on experimental data to reconstruct the two-dimensional transverse emittance of the Clinton P. Anderson Meson Physics Facility (LAMPF) proton beam at 100 MeV and the H/sup -/ beam at 750 keV. Wire scanners at three stations were used to get the one-dimensional profiles. Results will be compared with those gained using the destructive slit and collector method and with those gained using MART (Multiplicative Algebraic Reconstruction Technique) on the same three profiles.
Date: January 1, 1979
Creator: Sander, O.R.; Minerbo, G.N.; Jameson, R.A. & Chamberlin, D.D.
Partner: UNT Libraries Government Documents Department

Electron beam experiments at Maryland University

Description: An experimental study of the stability of intense electron beams is described. The purpose is to determine the emittance growth associated with aberrations arising from the non-uniform transverse density distribution in the beam, and to compare measurements with the results of computer simulations. (GHT)
Date: January 1, 1979
Creator: Brennan, M.A.; Loschialpo, P.; Namkung, W.; Reiser, M. & Lawson, J.D.
Partner: UNT Libraries Government Documents Department

High intensity beam profile monitors for the LAMPF primary beam lines

Description: Two types of beam profile monitors are in use at LAMPF to measure the properties of the 800 MeV, 500 ..mu..A proton beam external to the linac. Both types use secondary electron emission from a wire to produce a current signal proportional to the amount of proton beam that intercepts the wire. The wire scanner system uses a pair of orthogonal wires which are passed through the beam and the harp system uses two fixed planes of parallel wires. Most of the harps are not retractable and are exposed continuously to the primary beam. The high beam intensities available lead to a number of technical problems for instruments that intercept the beam or are close to primary beam targets. The thermal, electrical, radiation-damage, and material selection problems encountered, and some solutions which have been implemented are discussed.
Date: January 1, 1979
Creator: Hoffman, E.W.; Macek, R.J.; van Dyck, O.; Lee, D.; Harvey, A.; Bridge, J. et al.
Partner: UNT Libraries Government Documents Department

Noninteractive beam position and size monitor for heavy ions

Description: The Ion Beam Fusion development program at Argonne National Laboratory requires noninteractive size measurements of a pulsed, 30 mA, Xe/sup +1/ particle beam. Pulses of 100 ..mu..s duration will be produced by the 1.5 MV preaccelerator; therefore, fast response diagnostics are required. Techniques of utilizing residual gas ionization to profile particle beams have been reported before. This paper discusses the development of vertical and horizontal beam profile monitors that are synchronously clocked to interface with oscilloscopes and computers. Modern integrated circuitry is utilized which boosts performance to a point where pulses as short as 20 ..mu..s can be analyzed. A small, simple ionization chamber is shown which provides sixteen channels of position resolution over 12 cm of aperture.
Date: January 1, 1979
Creator: Bogaty, J.M.
Partner: UNT Libraries Government Documents Department

Recent improvements in beam diagnostic instrumentation

Description: In high-current machines, such as LAMPF and the envisioned Hanford Engineering Development Laboratory (HEDL) Fusion Materials Irradiation Test (FMIT) Facility linac, hands-on maintenance is desired Beam spill must be kept extremely low; therefore, attention must be given to beam fringes (tails). Beam matching to the structure becomes increasingly important. Equipment capable of accurately measuring transverse beam profiles over a range spanning more than four orders of magnitude and longitudinal phase profiles over ranges spanning more than three orders of magnitude is described. Errors in 100-MeV transverse emittance measurements are explored and experimental emittance measurements made with three different methods are compared. Advantages of one nondestructive method are developed.
Date: January 1, 1979
Creator: Sander, O.R.; Jameson, R.A. & Patton, R.D.
Partner: UNT Libraries Government Documents Department

Computed tomographic reconstruction of beam profiles with a multi-wire chamber

Description: MEDUSA (MEdical Dose Uniformity SAmpler), a 16 plane multi-wire proportional chamber, has been built to accurately measure beam profiles. The large number of planes allows for reconstruction of highly detailed beam intensity structures by means of Fourier convolution reconstruction techniques. This instrument is being used for verification and tuning of the Bevalac radiotherapy beams, but has potential applications in many beam profile monitoring situations.
Date: March 1, 1979
Creator: Alonso, J.R.; Tobias, C.A. & Chu, W.T.
Partner: UNT Libraries Government Documents Department

Synchrotron radiation from a Helical Wiggler

Description: The use of Wiggler magnets as an improved source of synchrotron radiation from high energy electron storage rings was proposed a few years ago. Since then it has also been suggested that synchrotron radiation from Wiggler magnets placed in proton machines can be used to monitor energy, dimensions and position of the beam and that this effect is even more interesting in proton storage rings where the need to see the beam is greater. Most of the calculations carried out so far consider radiation from a single particle in a Wiggler which is appropriate when the beam is radiating incoherently. In this paper a general formalism is developed for the case when the beam radiates coherently. These results are then applied to both electron and proton storage rings. For the electron case, an expression is derived for the length of the bunch to be used as a more intense coherent radiation source. For proton machines the radiation can be used to measure energy, current, transverse dimensions and longitudinal density variations in the beam.
Date: August 1, 1979
Creator: Irani, A.A.
Partner: UNT Libraries Government Documents Department

Radio-frequency quadrupole linear accelerator

Description: The radio-frequency quadrupole (RFQ) is a new linear accelerator concept in which rf electric fields are used to focus, bunch, and accelerate the beam. Because the RFQ can provide strong focusing at low velocities, it can capture a high-current dc ion beam from a low-voltage source and accelerate it to an energy of 1 MeV/nucleon within a distance of a few meters. A recent experimental test at the Los Alamos Scientific Laboratory (LASL) has confirmed the expected performance of this structure and has stimulated interest in a wide variety of applications. The general properties of the RFQ are reviewed and examples of applications of this new accelerator are presented.
Date: January 1, 1980
Creator: Wangler, T.P. & Stokes, R.H.
Partner: UNT Libraries Government Documents Department

Beam measurements on Argonne linac for collider injector design

Description: The 20 MeV electron linac at Argonne produces 5 x 10/sup 10/ electrons in a single bunch. This amount of charge per bunch is required for the proposed single pass collider at SLAC. For this reason the characteristics of the beam from this machine are of interest. The longitudinal charge distribution has been measured by a new technique. The technique is a variation on the deduction of bunch shape from a spectrum measurement. Under favorable conditions a resolution of about 1/sup 0/ of phase is possible, which is considerably better than can be achieved with streak cameras. The bunch length at 4.5 x 10/sup 10/ e/sup -/ per bunch was measured to be 15/sup 0/ FWHM. The transverse emittance has also been measured using standard techniques. The emittance is 16 mm-mrad at 17.2 MeV.
Date: July 1, 1980
Creator: James, M.B.; Koontz, R.F. & Miller, R.H.
Partner: UNT Libraries Government Documents Department

Brookhaven four-stage accel-decel production of low-energy highly stripped heavy ions

Description: The dual MP tandem facility at Brookhaven has been used in a four-stage accel-decel mode to produce highly stripped S ion beams (Q = 10-16/sup +/). Fully stripped S ions were obtained at energies down to 8 MeV. The low energy limit is presently due to the inclined field configuration of the last acceleration tube.
Date: January 1, 1981
Creator: Barrette, J. & Thieberger, P.
Partner: UNT Libraries Government Documents Department