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Low-energy demonstration accelerator (LEDA) test results and plans

Description: The LEDA 75-keV injector and 6.7-MeV RFQ have been tested with pulsed and cw proton beam currents up to 100 mA. Several LINAC2000 papers give the results of those measurements. A follow-on experiment, to intentionally introduce and measure beam halo on the RFQ output beam, is reported in several papers at this conference (PAC2001). In this paper we summarize the LEDA RFQ commissioning results and the beam-halo measurements and we discuss future test plans for this high-current, high-average-power rf structures test bed.
Date: January 1, 2001
Creator: Smith, H. V. (Horace V.); Schneider, J. D. (J. David) & Sheffield, R. L. (Richard L.)
Partner: UNT Libraries Government Documents Department

Development of a 110-m-mA, 75-keV proton injector for high-current, CW linacs

Description: A dc proton injector is being developed for a 6.7 MeV CW RFQ at Los Alamos. The RFQ input beam requirements are 75 keV energy, 110 mA dc proton current, and 0.20 {pi}mm-mrad rms normalized emittance. The injector has now produced a 75-keV, 117-mA dc proton beam (130 mA total current) with the required emittance. The emittance has been measured after a 2.1 m long two-solenoid beam transport system. The measured emittance can be explained in terms of the ion source emittance and beam transport through the focusing elements. Measured proton fractions are 90-92% of the beam current. Engineering of the accelerating column high-voltage design is being improved to increase the injector reliability. Injector design details and status are presented.
Date: September 1, 1996
Creator: Sherman, J.D.; Bolme, G.O. & Hansborough, L.D.
Partner: UNT Libraries Government Documents Department

Commissioning plan for a high-current proton linac

Description: High-power proton linacs (E>500 MeV) are potentially useful for transmutation applications, such as the production of tritium. In production applications, high availability is essential. Achieving high availability requires an accelerator design that simplifies maintenance and accommodates commissioning procedures designed to minimize tune-up time. These are worthwhile goals for any accelerator, but the very high beam powers (170 MW) and heavy beam loading of the Accelerator Production of Tritium (APT) linac introduce significant new challenges. This paper will describe the commissioning plan, as developed to date.
Date: September 1, 1997
Creator: Chan, K.C.D.; Barber, R.L. & Garnett, R.W.
Partner: UNT Libraries Government Documents Department

Physics design of APT linac with normal conducting rf cavities

Description: The accelerator based production of tritium calls for a high-power, cw proton linac. Previous designs for such a linac use a radiofrequency quadrupole (RFQ), followed by a drift-tube linac (DTL) to an intermediate energy and a coupled-cavity linc (CCL) to the final energy. The Los Alamos design uses a high-energy (6.7 MeV) RFQ followed by the newly developed coupled-cavity drift-tube linac (CCDTL) and a CCL. This design accommodates external electromagnetic quadrupole lenses which provide a strong uniform focusing lattice from the end of the RFQ to the end of the CCL. The cell lengths in linacs of traditional design are typically graded as a function of particle velocity. By making groups of cells symmetric in both the CCDTL and CCL, the cavity design as well as mechanical design and fabrication is simplified without compromising the performance. At higher energies, there are some advantages of using superconducting rf cavities. Currently, such schemes are under vigorous study. This paper describes the linac design based on normal conducting cavities and presents simulation results.
Date: September 1, 1996
Creator: Nath, S.; Billen, J.H.; Stovall, J.E.; Takeda, Harunori & Young, L.M.
Partner: UNT Libraries Government Documents Department

Medium Beta Superconducting Accelerating Structures

Description: While, originally, the development of superconducting structures was cleanly divided between low-beta resonators for heavy ions and beta=1 resonators for electrons, recent interest in protons accelerators (high and low current, pulsed and cw) has necessitated the development of structures that bridge the gap between the two. These activities have resulted both in new geometries and in the adaptation of well-known geometries optimized to this intermediate velocity range. Their characteristics and properties are reviewed.
Date: September 1, 2001
Creator: Delayen, Jean
Partner: UNT Libraries Government Documents Department

Targetry issues for the Fermilab 2-MW neutrino superbeam

Description: The possibility to use various target materials are studied for a 2 MW neutrino superbeam facility that can be built at Fermilab utilizing the Main Injector and a Proton Driver. A simple target solution found is a thick graphite rod taking a broad proton beam.
Date: June 27, 2002
Creator: al., Mikhail A Kostin et
Partner: UNT Libraries Government Documents Department

Recent transition crossing results from the Fermilab Main Ring

Description: This paper outlines the known mechanisms for emittance dilution and beam loss during transition crossing. These include scraping, Johnsen`s nonlinear effect, bunch length mismatch, microwave and negative-mass instabilities, and beam loading. A recent experiment on transition crossing performed with 13 proton bunches injected into the Main Ring is discussed.
Date: March 1, 1997
Creator: Bhat, C.M. & Ng, K.Y.
Partner: UNT Libraries Government Documents Department

Brookhaven National Laboratory (BNL) Proton Beam Characteristics and Dynamics: A First Look

Description: This report is the first in a series addressing issues that affect the quantitative conclusions of proton radiographic analysis. In this paper we begin studying the dynamics and measurement of the proton beam profile. We conclude with a plan for further study.
Date: August 1, 2000
Creator: Vixie, K.R. & Sandine, G.L.
Partner: UNT Libraries Government Documents Department

Pre-Conceptual Design and Preliminary Neutronic Analysis of the Proposed National Spallation Neutron Source (NSNS)

Description: The Department of Energy (DOE) has initiated a pre-conceptual design study for the National Spallation Neutron Source (NSNS) and given preliminary approval for the proposed facility to be built at Oak Ridge National Laboratory (ORNL). The pre-conceptual design of the NSNS initially consists of an accelerator system capable of delivering a 1 to 2 GeV proton beam with 1 MW of beam power in an approximate 0.5 {micro}s pulse at a 60 Hz frequency onto a single target station. The NSNS will be upgradable to a significantly higher power level with two target stations (a 60 Hz station and a 10 Hz station). There are many possible layouts and designs for the NSNS target stations. This paper gives a brief overview of the proposed NSNS with respect to the target station, as well as the general philosophy adopted for the neutronic design of the NSNS target stations. A reference design is presented, and some preliminary neutronic results for the NSNS are briefly discussed.
Date: August 1, 2001
Creator: Johnson, JO
Partner: UNT Libraries Government Documents Department

A STUDY ON THE CHOICE OF PARAMETERS FOR A HIGH ENERGY ELECTRON RING ACCELERATOR

Description: The production of high energy (multi-GeV) proton beams by an electron ring accelerator is considered. Both the final energy and intensity of the proton beam depend on the choice of parameters for the electron ring. Possible sets of parameters, consistent with all the known requirements of ring stability, and which optimize the energy and (or) the intensity of the proton beam, are presented.
Date: June 26, 1970
Creator: Bovet, C. & Pellegrini, C.
Partner: UNT Libraries Government Documents Department

Beam instabilities in very large hadron collider

Description: The Very Large Hadron Collider (VLHC) is a supercon-ducting proton-proton collider with approximately 100 TeV cm and approximately 10{sup 34} s{sup -1}cm{sup -2} luminosity [1]. Currently, beam dynamics in this future accelerator is the subject of intensive studies within the framework of the US-wide VLHC R&D program. This presentation sum-marizes recent developments in the field. Besides general discussion on relevant VLHC parameters, we consider various beam instabilities and ways to avoid them. Finally, we outline possibilities for theoretical and experimental R&D.
Date: May 11, 1999
Creator: Marriner, J.; Danilov, V. & Shiltsev, V.
Partner: UNT Libraries Government Documents Department

DX magnet requirements for p-Au operation

Description: This document addresses the question of moving the DX magnets for p-Au operations. First the beam geometry is addressed. Next, the beam sizes are covered. Finally, a conclusion is presented.
Date: January 19, 2012
Creator: Tepikian, S.; Trbojevic&#44 & D.
Partner: UNT Libraries Government Documents Department

Handbook of Accelerator Physics and Engineering (sections 2.7.1 - 2.7.5 and 7.6.2)

Description: The sections written by this author are: 2.7.1- Thomas - BMT equation; 2.2.2- Spinor Algebra; 2.7.3- Spin Rotators and Siberian Snakes; 2.7.4- Ring with Spin Rotator and Siberian Snakes; 2.7.5- Depolarizing Resonances and Spin Flippers; & 7.6.2- Proton Beam Polarimeters
Date: April 19, 1999
Creator: Roser, T.
Partner: UNT Libraries Government Documents Department

STUDY OF GRAPHITE TARGETS INTERACTING WITH THE 24 GEV PROTON BEAM OF THE BNL MUON TARGET EXPERIMENT.

Description: A tightly focused beam on target is required in the muon collider/neutrino factory study. Specifically, up to 16 TP (1 TP = 10{sup 12} protons) per pulse of a 24 GeV proton beam are to be delivered on target, with a pulse length of a few microseconds and a beam spot of 1.5 mm rms sigma. Experiment E951 at BNL was set up to explore the potential of various target materials. Target integrity issues leads one to consider low-Z materials as potential targets. Thus, in the first phase of the E951 experiment, graphite and carbon-carbon composite targets were exposed to the AGS beam and their response to the induced thermal shock was studied. This paper presents theoretical prediction results as well as experimental results and makes an assessment of the abilities of prediction models to capture the dynamic response of the solid target.
Date: June 2, 2002
Creator: SIMOS,N.; KIRK,H.; KAHN,S.; MCDONALS,K.; CATES,M.; RIEMER,B. et al.
Partner: UNT Libraries Government Documents Department

Electron-proton instability in the IPNS-Upgrade RCS: Part I

Description: The electron-proton instability in the IPNS-Upgrade RCS is investigated in this report. A dispersion relation applicable to the coasting beam is derived, and the approximations used are stated in order to facilitate the understanding of the underlying mechanism of the instability. The threshold of instability in terms of neutralization of the circulating beam is found for the IPNS-Upgrade RCS. The dependence of threshold on the beam size and the lattice tune is also studied and its numerical results are presented.
Date: February 27, 1995
Creator: Chae, Yong-Chul
Partner: UNT Libraries Government Documents Department

TUNING SECTION 2 OF THE LEDA CCDTL

Description: As part of the Low-Energy Demonstration Accelerator (LEDA) portion of the Advanced Accelerator Applications (AAA) project we have fabricated and will perform high-power RF tests on Section 2 of the 700-MHz Coupled-Cavity Drift-Tube Linac (CCDTL). This CCDTL section contains six, two-gap accelerating cells. This portion of the CCDTL was designed to accelerate the 100-mA, LEDA RFQ proton beam to 7.3 MeV. This paper reports on the process and results of tuning Section 2 leading up to high-power RF testing.
Date: June 1, 2001
Creator: Rybarcyk, L. & Wood, R
Partner: UNT Libraries Government Documents Department

Excitation Curves of C12(p,pn)C11 and B11(p,n)C11 up to 32 MeV.

Description: The reaction C{sup 12} (p,pn)C{sup 11} which has been studied by McMillan, Chubb and Miller for energies up to 100 Mev is an example of a reaction whose high energy behavior cannot be explained by a compound nucleus process. The purpose of the study was to investigate this reaction at the high resolution possible with the Berkeley linear accelerator near the excitation threshold. The excitation curve was obtained by stacking specially molded polystyrene (composition C{sub n}H{sub n}) foils of high uniformity and bombarding them in the proton beam. The resultant activity was then counted on a Geiger counter in standard geometry. The resultant curve is shown in Figure 1. An immediately evident feature is the sharp threshold of the reaction. The second derivative curve, illustrated in Figure 2, of the excitation shows an RMS width of 270 kV, the theoretical straggling width due to the foils of 170 kv, and the remaining width in accordance with the energy spread of approximately {+-} 100 kv half width of the linear accelerator. The data therefore are compatible with a sharp threshold for this reaction. This curve, incidentally, furnishes independent evidence as to the energy homogeneity of the linear accelerator beam.
Date: April 20, 1948
Creator: Phillips, Robert & Panofsky, Wolfgang K.H.
Partner: UNT Libraries Government Documents Department

The Production of Thin Be Foils

Description: A procedure for making Be foils between 10{sup -5} cm. and 10{sup -3} cm. thick, and with diameters up to an inch and a half is described, and methods of mounting these foils are indicated.The problem of making thin Be foils was presented in connection with focusing the proton beam in the Berkeley Linear Accelerator, and although the foils are not now used in the accelerator, they have proved to be quite useful as thin targets, target supports, thin windows, etc. The Be was evaporated in vacuum and deposited on a metal collector plate. The problems encountered were: (1) obtaining reproducible quantities of evaporated Be; (2) stripping of Be from the collector plates; (3) preventing curl of the foils when they were stripped; and (4) mounting the foils.
Date: March 18, 1948
Creator: Bradner, Hugh
Partner: UNT Libraries Government Documents Department

TUNING SECTION 2 OF THE LEDA CCDTL

Description: As part of the Low-Energy Demonstration Accelerator (LEDA) portion of the Advanced Accelerator Applications (AAA) project we have fabricated and will perform high-power RF tests on Section 2 of the 700-MHz Coupled-Cavity Drift-Tube Linac (CCDTL). This CCDTL section contains six, two-gap accelerating cells. This portion of the CCDTL was designed to accelerate the 100-mA, LEDA RFQ proton beam to 7.3 MeV. This paper reports on the process and results of tuning Section 2 leading up to high-power RF testing.
Date: January 1, 2001
Creator: Rybarcyk, L. J. (Lawrence J.); L.), Wood R. L. (Richard; Leslie, P. O. (Paul O.); Valdiviez, R. (Robert); Cole, M. D. (Michael D.) & Potter, J. M. (James M.)
Partner: UNT Libraries Government Documents Department