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Experimental demonstration of two beam acceleration using dielectric step-up transformer.

Description: We report on the experimental results of the dielectric based two beam accelerator (step-up transformer). By using a single high charge beam, we have generated and extracted a high power RF pulse from a 7.8 GHz primary dielectric structure and then subsequently transferred to a second accelerating structure with higher dielectric constant and smaller transverse dimensions. We have measured the energy change of a second (witness) beam passing through the acceleration stage. The measured gradient is > 4 times the deceleration gradient. The detailed experiment of set-up and results of the measurements are discussed. Future plans for the development of a 100 MeV demonstration accelerator based on this technique is presented.
Date: July 17, 2001
Creator: Gai, W.; Conde, M.E.; Konecny, R.; Power, J.G.; Schoessow, P.; Simpson, J. et al.
Partner: UNT Libraries Government Documents Department


Description: The M6 working group had more than 40 active participants (listed in Section 4). During the three weeks at Snowmass, there were about 50 presentations, covering a wide range of topics associated with high intensity proton sources. The talks are listed in Section 5. This group also had joint sessions with a number of other working groups, including E1 (Neutrino Factories and Muon Colliders), E5 (Fixed-Target Experiments), M1 (Muon Based Systems), T4 (Particle Sources), T5 (Beam dynamics), T7 (High Performance Computing) and T9 (Diagnostics). The M6 group performed a survey of the beam parameters of existing and proposed high intensity proton sources, in particular, of the proton drivers. The results are listed in Table 1. These parameters are compared with the requirements of high-energy physics users of secondary beams in Working Groups E1 and E5. According to the consensus reached in the E1 and E5 groups, the U.S. HEP program requires an intense proton source, a 1-4 MW Proton Driver, by the end of this decade.
Date: August 14, 2001
Creator: CHOU,W. & WEI,J.
Partner: UNT Libraries Government Documents Department

Performance of the KTeV high-energy neutral kaon beam at Fermilab

Description: The performance of the primary and secondary beams for the KTeV experiments E832 and E799-II is reviewed. The beam was commissioned in the summer of 1996 and initially operated for approximately one year. The report includes results on the primary beam, target station including primary beam dump and muon sweeping system, neutral beam collimation system, and alignment.
Date: June 1, 1998
Creator: Bocean, V.
Partner: UNT Libraries Government Documents Department

Report of the Snowmass T4 working group on particle sources: Positron sources, anti-proton sources and secondary beams

Description: This report documents the activities of the Snowmass 2001 T4 Particle Sources Working Group. T4 was charged with examining the most challenging aspects of positron sources for linear colliders and antiproton sources for proton-antiproton colliders, and the secondary beams of interest to the physics community that will be available from the next generation of high-energy particle accelerators. The leading issues, limiting technologies, and most important R and D efforts of positron production, antiproton production, and secondary beams are discussed in this paper. A listing of T4 Presentations is included.
Date: December 5, 2002
Creator: al., N. Mokhov et
Partner: UNT Libraries Government Documents Department


Description: Strongly pulsed proton beams for secondary beam production are required for projects such as pulsed spallation neutron sources or neutrino factories where accurate time-of-flight information is required. To meet these demands techniques to produce multi-GeV proton bunches with very high longitudinal brightness are being developed. A review of the present status is presented.
Date: June 18, 2001
Creator: ROSER,T.
Partner: UNT Libraries Government Documents Department

Report to users of ATLAS - September 1998.

Description: The ATLAS facility has provided a total of 5749 hours of beam for research in FY1998. The accelerator operation had a very high 93% reliability factor during that period. With the startup of Gammasphere in January, our schedule has attempted to minimize scheduled downtime and maximize beam-time for research. Our best performance so far occurred during the month of May when a total of 639 hours was provided for research. From the accelerator point-of-view, recent major highlights have included first operation of a new production configuration for our {sup 17}F beams which increased the beam current on-target to 2 x 10{sup 6} {sup 17}F ions/see. The {sup 17}F production target was moved approximately 4 meters upstream and a new superconducting solenoid was added to the system to refocus the highly divergent secondary beam. This new location also places the target upstream of a new superconducting resonator which was used to reduce the energy spread of the beam delivered to the spectrograph to less than 300 keV (FWHM). An improved, liquid nitrogen cooled, multiple gas cell has also significantly contributed to better performance.
Date: November 18, 1998
Creator: Ahmad, I. & Hofman, D.
Partner: UNT Libraries Government Documents Department

Accelerator development for a radioactive beam facility based on ATLAS.

Description: The existing superconducting linac ATLAS is in many respects an ideal secondary beam accelerator for an ISOL (Isotope separator on-line) type radioactive beam facility. Such a facility would require the addition of two major accelerator elements: a low charge state injector for the existing heavy ion linac, and a primary beam accelerator providing 220 MV of acceleration for protons and light ions. Development work for both of these elements, including the option of superconducting cavities for the primary beam accelerator is discussed.
Date: January 8, 1998
Creator: Shepard, K. W.
Partner: UNT Libraries Government Documents Department

Transverse beam shape measurements of intense proton beams using optical transition radiation

Description: A number of particle physics experiments are being proposed as part of the Department of Energy HEP Intensity Frontier. Many of these experiments will utilize megawatt level proton beams onto targets to form secondary beams of muons, kaons and neutrinos. These experiments require transverse size measurements of the incident proton beam onto target for each beam spill. Because of the high power levels, most beam intercepting profiling techniques will not work at full beam intensity. The possibility of utilizing optical transition radiation (OTR) for high intensity proton beam profiling is discussed. In addition, previous measurements of OTR beam profiles from the NuMI beamline are presented.
Date: March 1, 2012
Creator: Scarpine, Victor E.
Partner: UNT Libraries Government Documents Department

P-West High Intensity Secondary Beam Area Design Report

Description: This report gives the initial design parameters of a 1000 GeV High Intensity Superconducting Secondary Beam Laboratory to be situated in the Proton Area downstream of the existing Proton West experimental station. The area will provide Fermilab with a major capability for experimentation with pion and antiproton beams of intensities and of energies available at no other laboratory and with an electron beam with excellent spot size, intensity, and purity at energies far above that available at electron machines. Detailed beam design, area layouts, and cost estimates are presented, along with the design considerations.
Date: March 1, 1977
Creator: Cox, A.; Currier, R.; Eartly, D.; Guthke, A.; Johnson, G.; Lee, D. et al.
Partner: UNT Libraries Government Documents Department


Description: Rapid cycling synchrotrons are used to accelerate high-intensity proton beams to energies of tens of GeV for secondary beam production. After primary beam collision with a target, the secondary beam can be collected, cooled, accelerated or decelerated by ancillary synchrotrons for various applications. In this paper, we first present a lattice for the main synchrotron. This lattice has: (a) flexible momentum compaction to avoid transition and to facilitate RF gymnastics (b) long straight sections for low-loss injection, extraction, and high-efficiency collimation (c) dispersion-free straights to avoid longitudinal-transverse coupling, and (d) momentum cleaning at locations of large dispersion with missing dipoles. Then, we present a lattice for a cooler ring for the secondary beam. The momentum compaction across half of this ring is near zero, while for the other half it is normal. Thus, bad mixing is minimized while good mixing is maintained for stochastic beam cooling.
Date: June 23, 2006
Creator: WANG, S.; WEI, J.; BROWN, K.; GARDNER, C.; LEE, Y.Y.; LOWENSTEIN, D. et al.
Partner: UNT Libraries Government Documents Department

The first production and transport of radioactive {sup 17}F at ATLAS for research

Description: A secondary beam of radioactive {sup 17}F was produced at the ATLAS accelerator and delivered to an experimental target station with an intensity of at least 2 x 10{sup 5} particles per second for use in the research program. The beam was produced through the p({sup 17}O, {sup 17}F)n inverse reaction by bombarding a hydrogen gas target with 250 particle nA of 83 MeV {sup 17}O from the ATLAS superconducting linac. The gas target was maintained at a pressure of 300 Torr and a temperature of 257 K. Beam quality was dominated by multiple scattering in the gas cell windows and by the reaction kinematics and beamline acceptance for energy spread.
Date: October 1, 1996
Creator: Harss, B.; Berger, J.C. & Greene, J.
Partner: UNT Libraries Government Documents Department

Report of the Snowmass M6 Working Group on high intensity proton sources

Description: The U.S. high-energy physics program needs an intense proton source, a 1-4 MW Proton Driver (PD), by the end of this decade. This machine will serve as a stand-alone facility that will provide neutrino superbeams and other high intensity secondary beams such as kaons, muons, neutrons, and anti-protons (cf. E1 and E5 group reports) and also serve as the first stage of a neutrino factory (cf. M1 group report). It can also be a high brightness source for a VLHC. Based on present accelerator technology and project construction experience, it is both feasible and cost-effective to construct a 1-4 MW Proton Driver. Two recent PD design studies have been made, one at FNAL and the other at the BNL. Both designed PD's for 1 MW proton beams at a cost of about U.S. $200M (excluding contingency and overhead) and both designs were upgradeable to 4 MW. An international collaboration between FNAL, BNL and KEK on high intensity proton facilities is addressing a number of key design issues. The superconducting (sc) RF cavities, cryogenics, and RF controls developed for the SNS can be directly adopted to save R&D efforts, cost, and schedule. PD studies are also actively being pursued at Europe and Japan.
Date: August 20, 2002
Creator: Wei, Weiren Chou and J.
Partner: UNT Libraries Government Documents Department

KTeV beam systems design report

Description: The primary and secondary beams for the KTeV experiments E799-II and E832 are discussed. The specifications are presented and justified. The technical details of the implementation of the primary beam transport and stability are detailed. The target, beam dump, and radiation safety issues are discussed. The details of the collimation system for the pair of secondary beams are presented.
Date: September 1, 1997
Creator: Bocean, V.; Childress, S. & Coleman, R.
Partner: UNT Libraries Government Documents Department


Description: The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with {approximately}100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DC-magnetron sputtering were conducted in a test chamber of relevant geometry to SNS ring vacuum chambers. Auger Electron Spectroscopy (AES) and Rutherford Back Scattering (RBS) were used to analyze the coatings for thickness, stoichiometry and impurity. Excellent results were obtained with magnetron sputtering. The development of the parameters for the coating process and the surface analysis results are presented.
Date: June 18, 2001
Creator: HE,P.; HSEUH,H.C.; MAPES,M.; TODD,R. & WEISS,D.
Partner: UNT Libraries Government Documents Department

Design and measurements of a deflecting mode cavity for an RF separator

Description: The Fermilab Main Injector can produce intense 120 GeV/c proton beams for fixed target experimentation. Two deflecting mode RF systems can be used to separate charged kaons from a momentum selected secondary beam, consisting of pions, kaons and protons, using a time of flight method. We present the RF design of a 3.9 GHz superconducting cavity which operates in the deflecting (TM110) pi-mode and the dependence of the RF parameters on the cavity shape, as determined with finite difference calculations. End cell compensation has been treated, providing cell-to-cell field flatness. First results from measurements on a prototype cavity are shown. We demonstrated that it is possible to tune the deflecting mode of a cell cavity with bead pull measurements. Effects relating the polarization of the modes are discussed.
Date: July 9, 2001
Creator: Bellantoni, Leo
Partner: UNT Libraries Government Documents Department

In-beam production and transport of radioactive {sup 17}F at ATLAS.

Description: Beam currents of radioactive {sup 17}F(T{sub 1/2} = 65s) as high as 2 x 10{sup 6} s{sup {minus}1} have been produced at the ATLAS facility and delivered to target for nuclear physics research. The d({sup 16}O, {sup 17}F)n and p({sup 17}O,{sup 17}F)n reaction were used to produce the {sup 17}F in the energy range of 65-110 MeV with {sup 17}F intensities of up to 250 pnA. The target employed is a liquid nitrogen cooled H{sub 2} gas cell, with HAVAR windows, operating at up to 8 x 10{sup 4} Pa pressure. A new beam optics geometry consisting of a superconducting solenoid immediately after the production target followed by a single superconducting resonator has significantly improved the total capture efficiency of the transport system. The superconducting solenoid captures the highly divergent secondary beam and refocuses it to improve the beam match into the remainder of the transport system. A single superconducting resonator then ''debunches'' the beam, reducing the energy spread by a factor of four. The beam energy can also be varied, using the resonant cavity, without changing the primary beam energy. Detailed discussion of the results, comparison to calculations, and further possible improvements will be presented.
Date: November 30, 1998
Creator: Pardo, R. 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

Theory and measurement of the electron cloud effect.

Description: Photoelectrons produced through the interaction of synchrotrons radiation and the vacuum chamber walls can be accelerated by a charged particle beam, acquiring sufficient energy to produce secondary electrons (SES) in collisions with the walls. If the secondary-electron yield (SEY) coefficient of the wall material is greater than one, a run-away condition can develop. In addition to the SEY, the degree of amplification depends on the beam intensity and temporal distribution. As the electron cloud builds up along a train of stored bunches, a transverse perturbation of the head bunch can be communicated to trailing bunches in a wakefield-like interaction with the cloud. The electron cloud effect is especially of concern for the high-intensity PEP-II (SLAC) and KEK B-factories and at the Large Hadron Collider (LHC) at CERN. An initiative was undertaken at the Advanced Photon Source (APS) storage ring to characterize the electron cloud in order to provide realistic limits on critical input parameters in the models and improve their predictive capabilities. An intensive research program was undertaken at CERN to address key issues relating to the LHC. After giving an overview, the recent theoretical and experimental results from the APS and the other laboratories will be discussed.
Date: April 29, 1999
Creator: Harkey, K. C.
Partner: UNT Libraries Government Documents Department

Measurements of the electron cloud in the APS storage ring.

Description: Synchrotron radiation interacting with the vacuum chamber walls in a storage ring produce photoelectrons that can be accelerated by the beam, acquiring sufficient energy to produce secondary electrons in collisions with the walls. If the secondary-electron yield (SEY) coefficient of the wall material is greater than one, as is the case with the aluminum chambers in the Advanced Photon Source (APS) storage ring, a runaway condition can develop. As the electron cloud builds up along a train of stored positron or electron bunches, the possibility exists that a transverse perturbation of the head bunch will be communicated to trailing bunches due to interaction with the cloud. In order to characterize the electron cloud, a special vacuum chamber was built and inserted into the ring. The chamber contains 10 rudimentary electron-energy analyzers, as well as three targets coated with different materials. Measurements show that the intensity and electron energy distribution are highly dependent on the temporal spacing between adjacent bunches and the amount of current contained in each bunch. Furthermore, measurements using the different targets are consistent with what would be expected based on the SEY of the coatings. Data for both positron and electron beams are presented.
Date: April 16, 1999
Creator: Harkey, K. C.
Partner: UNT Libraries Government Documents Department

An advanced ISOL facility based on ATLAS.

Description: The Argonne concept for an accelerator complex for efficiently producing high-quality radioactive beams from ion source energy up to 6-15 MeV/u is described. The Isotope-Separator-On-Line (ISOL) method is used. A high-power driver accelerator produces radionuclides in a target that is closely coupled to an ion source and mass separator. By using a driver accelerator which can deliver a variety of beams and energies the radionuclide production mechanisms can be chosen to optimize yields for the species of interest. To effectively utilize the high beam power of the driver two-step target/ion source geometries are proposed (1) Neutron production with intermediate energy deuterons on a primary target to produce neutron-rich fission products in a secondary {sup 238}U target, and (2) Fragmentation of neutron-rich heavy ion rich fission products in a secondary beams such as {sup 18}O in a target/catcher geometry. Heavy ion beams with total energies in the 1-10 GcV range are also available for radionuclide production via high-energy spallation reactions. At the present time R and D is in progress to develop superconducting resonator structures for a driver linac to cover the energy range up to 100 MeV per nucleon for heavy ions and 200 MeV for protons. The post accelerator scheme is based on using existing ISOL-type 1+ ion source technology followed by CW Radio Frequency Quadruple (RFQ) accelerators and superconducting linacs including the present ATLAS accelerator. A full-scale prototype of the first-stage RFQ has been successfully tested with RF at full design voltage and tests with ion beams are in progress. A benchmark beam, {sup 132}Sn {at} 7 MeV/u, requires two stripping stages, one a gas stripper at very low velocity after the first RFQ section, and one a foil stripper at higher velocity after a superconducting-linac injector.
Date: February 24, 1999
Creator: Nolen, J. A.
Partner: UNT Libraries Government Documents Department