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A High-Current Radio-Frequency Ion Accellerator

Description: Abstract: "A radio-frequency ion accelerator is described which is capable of continuous currents of protons of 250 ma at an energy of 500 kev. The beam is less than 3 in. in diameter and has a divergence of less than 2 degree half angle. Operation of the machine accelerating deuterons to an energy of 1000 kev is also described."
Date: February 1957
Creator: Lamb, William A. S.; Hester, Ross E. & Kippenhan, Dean O.
Partner: UNT Libraries Government Documents Department

Linear Accelerator for Heavy Ions

Description: The following report discusses the construction of two heavy-ion linear accelerators, one at the the University of California Radiation Laboratory and the other at Yale University. The goal for these accelerators is to produce ions of masses up to that of neon with energies of 10 Mev per nucleon.
Date: March 27, 1959
Creator: Wells, Don
Partner: UNT Libraries Government Documents Department

Absolute beam flux measurement at NDCX-I using gold-melting calorimetry technique

Description: We report on an alternative way to measure the absolute beam flux at the NDCX-I, LBNL linear accelerator. Up to date, the beam flux is determined from the analysis of the beam-induced optical emission from a ceramic scintilator (Al-Si). The new approach is based on calorimetric technique, where energy flux is deduced from the melting dynamics of a gold foil. We estimate an average 260 kW/cm2 beam flux over 5 {micro}s, which is consistent with values provided by the other methods. Described technique can be applied to various ion species and energies.
Date: April 1, 2011
Creator: Ni, P. A.; Bieniosek, F. M.; Lidia, S. M. & Welch, J.
Partner: UNT Libraries Government Documents Department

Monthly Progress Report No. 57 for January 1948

Description: This report gives a short summary of the work done in the following fields for the month of January 1948: (1) 184-inch cyclotron; (2) 60-inch cyclotron; (3) synchrotron; (4) linear accelerator; (5) experimental physics; (6) theoretical physics; (7) isotope research; (8) chemistry; (9) medical physics; and (10) health physics and chemistry.
Date: January 1, 1948
Creator: Authors, Various
Partner: UNT Libraries Government Documents Department

Beam intensity expectations for a 200 MeV/u 400 kW radioactive beam driver accelerator.

Description: The expected radioactive ion production rate for a 200 MeV/u 400 kW driver linac using four different production methods is discussed. For each isotope the optimum method is identified and the rate is calculated based on different model assumptions, empirical observation and extrapolations. The results are compared to the rates expected for a 550 MeV proton driver machine with a beam power of 50 kW, as well as the full RIA facility with a 400 MeV/u 400 kW production linac.
Date: December 31, 2006
Creator: Back, B. B.; Jiang, C. L. & Physics
Partner: UNT Libraries Government Documents Department

Longitudinal Resistive Stability of an Intense Charge Bunch in a Linear Accelerator

Description: A simple, but realistic, model is used to theoretically investigate the longitudinal stability of a non-relativistic bunch in the limit of small wall resistivity compared to self-reactance. It is shown that to lowest order--and in contrast with an infinitely long beam--that an intense bunch is stable against longitudinal collective modes. It is concluded that an induction linac remains a viable option as a driver for heavy ion inertial fusion.
Date: July 1, 1980
Creator: Channell, P.J.; Wurtele, J.S. & Sessler, A.M.
Partner: UNT Libraries Government Documents Department

A method for measuring dark current electron beams in an rf linac

Description: X-ray fluorescence from thin foils inserted into the NPS linac has been used to measure the integrated electron beam intensity when the accelerator is operating with dark current. The measured x-ray flux, the known inner shell ionization cross sections and radiative transition probabilities are used to obtain measurements of dark currents of the order of 10{sup -14} amperes. The same arrangement allows continuous, in-situ energy calibration of our SiLi detector in the electromagnetic noise environment of the linac. This technique was orginally developed to perform absolute production efficiency measurements of parametric x-ray generation in the 5-50 keV range.
Date: December 31, 1993
Creator: Maruyama, X. K.; Fasanello, T.; Rietdyk, H.; Piestrup, M. A.; Rule, D. W. & Fiorito, R. B.
Partner: UNT Libraries Government Documents Department

Performance of the Argonne Wakefield Accelerator Facility and initial experimental results

Description: The Argonne Wakefield Accelerator facility has begun its experimental program. It is designed to address advanced acceleration research requiring very short, intense electron bunches. It incorporates two photocathode based electron sources. One produces up to 100 nC, multi-kiloamp `drive` bunches which are used to excite wakefields in dielectric loaded structures and in plasma. The second source produces much lower intensity `witness` pulses which are used to probe the fields produced by the drive. The drive and witness pulses can be precisely timed as well as laterally positioned with respect to each other. This paper discusses commissioning, initial experiments, and outline plans for a proposed 1 GeV demonstration accelerator.
Date: October 1, 1996
Creator: Gai, W.; Conde, M.; Cox, G.; Konecny, R.; Power, J.; Schoessow, P. et al.
Partner: UNT Libraries Government Documents Department

Beam break up analysis for the Berkeley femtosource

Description: We present a study of the single-bunch beam break up (BBU) instability for a proposed x-ray facility, based on a recirculating linac, to be built in Berkeley. The effects of injection errors, both position and angle, and of misalignments in the linac are investigated. We propose possible methods for limiting the consequent emittance increase.
Date: May 30, 2002
Creator: De Santis, Stefano & Zholents, Alexander A.
Partner: UNT Libraries Government Documents Department

High-Current Linear Accelerators

Description: This report analyzes two high-current linear accelerators, the A-54--a 48.5 megacycle resonant cavity accelerator--and the A-48, that is under construction during the time this report is written.
Date: June 27, 1955
Creator: Clark, A. F.; Jopson, R. C.; Lamb, W. A. S.; Smith, Lloyd & Van Atta, Chester Murray
Partner: UNT Libraries Government Documents Department

Parallel beam dynamics simulation of linear accelerators

Description: In this paper we describe parallel particle-in-cell methods for the large scale simulation of beam dynamics in linear accelerators. These techniques have been implemented in the IMPACT (Integrated Map and Particle Accelerator Tracking) code. IMPACT is being used to study the behavior of intense charged particle beams and as a tool for the design of next-generation linear accelerators. As examples, we present applications of the code to the study of emittance exchange in high intensity beams and to the study of beam transport in a proposed accelerator for the development of accelerator-driven waste transmutation technologies.
Date: January 31, 2002
Creator: Qiang, Ji & Ryne, Robert D.
Partner: UNT Libraries Government Documents Department

Recirculating Beam Breakup Study for the 12 GeV Upgrade at Jefferson Lab

Description: Two new high gradient C100 cryomodules with a total of 16 new cavities were installed at the end of the CEBAF south linac during the 2011 summer shutdown as part of the 12-GeV upgrade project at Jefferson Lab. We surveyed the higher order modes (HOMs) of these cavities in the Jefferson Lab cryomodule test facility and CEBAF tunnel. We then studied recirculating beam breakup (BBU) in November 2011 to evaluate CEBAF low energy performance, measure transport optics, and evaluate BBU thresholds due to these HOMs. This paper discusses the experiment setup, cavity measurements, machine setup, optics measurements, and lower bounds on BBU thresholds by new cryomodules.
Date: July 1, 2012
Creator: Ilkyoung Shin, Todd Satogata, Shahid Ahmed, Slawomir Bogacz, Mircea Stirbet, Haipeng Wang, Yan Wang, Byung Yunn, Ryan Bodenstein
Partner: UNT Libraries Government Documents Department

X-RAY ACTIVE MATRIX PIXEL SENSORS BASEDON J-FET TECHNOLOGY DEVELOPED FOR THE LINAC COHERENT LIGHT SOURCE.

Description: An X-ray Active Matrix Pixel Sensor (XAMPS) is being developed for recording data for the X-ray Pump Probe experiment at the Linac Coherent Light Source (LCLS). Special attention has to be paid to some technological challenges that this design presents. New processes were developed and refined to address problems encountered during previous productions of XAMPS. The development of these critical steps and corresponding tests results are reported here.
Date: October 29, 2007
Creator: CARINI,G.A.; CHEN, W.; LI, Z.; REHAK, P. & SIDDONS, D.P.
Partner: UNT Libraries Government Documents Department

Part II/Addendum Electron Beam Cooling between EBIS LINAC and Booster; Is Single Pass Cooling Possible?

Description: Due to some miscommunication, incomplete data was erroneously used in examining electron beam cooling for reducing momentum of gold ions exiting the EBIS LINAC before injection into the booster. Corrected calculations still indicate that single pass cooling is, in principle, feasible; momentum spread can be reduced by an order of magnitude in about one meter. Preliminary results suggest that this cooling deserves further consideration.
Date: July 1, 2008
Creator: Hershcovitch,A.
Partner: UNT Libraries Government Documents Department

Investigation of Beam Instability Under the Effects of Long-Range Transverse Wake Fields in the Berkeley Future Light Source

Description: An ultra-relativistic charged particle bunch moving through a resonator cavity leaves behind a wake field that will affect subsequent bunches (if the bunch is not ultra-relativistic, the wake field will not be exclusively behind it). If the initial bunch enters the cavity off-axis, it will produce a transverse wake field that can then kick later bunches off the axis. Thus, even bunches that were initially traveling on axis could be displaced and, in turn, produce their own transverse wake fields, affecting following bunches. The offsets obtained by bunches could increase along the bunch train, leading to the so-called multi-bunch beam break-up instability [1]. The purpose of our investigation is to see whether such instability will occur in the superconducting, 1.3 GHz, 2.5GeV linac (see Table 1) planned for the Berkeley future light source (BFLS). We assume an initial steady-state situation established for machine operation; i.e. a continuous process where every bunch follows the same trajectory through the linac, with only small deviations from the axis of the rf structures. We will look at a possible instability arising from a bunch having a small deviation from the established trajectory. Such a deviation would produce a wake field that is slightly different from the one produced by the bunches following the established trajectory. This could lead to subsequent bunches deviating further from the established trajectory. We will assume the deviations are small (at first) and so the difference in the wake field caused by a bunch not traveling along the established trajectory is well approximated by a long-range transverse dipole wake. We are concerned only with deviations from the established trajectory; thus, in our models, a transverse position of zero corresponds to the bunch traveling along the established trajectory. Under this assumption, only the additional long-range transverse dipole wake remains in our ...
Date: August 31, 2008
Creator: Kur, Eugene & Zholents, Alexander A.
Partner: UNT Libraries Government Documents Department

A FEMTOSECOND-LEVEL FIBER-OPTICS TIMING DISTRIBUTION SYSTEM USING FREQUENCY-OFFSET INTERFEROMETRY

Description: An optical fiber-based frequency and timing distribution system based on the principle of heterodyne interferometry has been in development at LBNL for several years. The fiber drift corrector has evolved from an RF-based to an optical-based system, from mechanical correctors (piezo and optical trombone) to fully electronic, and the electronics from analog to fully digital, all using inexpensive off-the-shelf commodity fiber components. Short-term optical phase jitter and long-term phase drift are both in the femtosecond range over distribution paths of 2 km or more.
Date: October 17, 2009
Creator: Staples, J.W.; Byrd, J.; Doolittle, L.; Huang, G. & Wilcox, R.
Partner: UNT Libraries Government Documents Department