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Double alpha MEBT for H{sup {minus}} beam

Description: This note describes simulation studies of the H{sup {minus}} beam matching condition between a 750keV rod radio-frequency quadrupole (RFQ) and the existing Fermilab drift tube linac (DTL). The RFQ design used in this study is that of an existing RFQ designed and built by A. Schempp from IAP-Goethe University. It is assumed that the medium-energy beam transport (MEBT) line uses hardware built for a positron emission tomography (PET) project. The MEBT is made out of two Alpha magnets and seven quadrupoles and was designed by D. Larson. The beam from the exit of the RFQ is matched to the entrance in the DTL in all three dimensions. The study shows that up to 65mA of H{sup {minus}} beam can be transported and cleanly injected into the present linac.
Date: January 4, 2001
Creator: Popovic, M.
Partner: UNT Libraries Government Documents Department

Fermilab Linac Upgrade: Module conditioning results

Description: The 805 MHz Side-coupled cavity modules for the Fermilab 400 MeV linac upgrade have been conditioned to accept full power. The sparking rate in the cavities and in the side-cells has been reduced to acceptable levels. It required approximately 40 [times] 10[sup 6] pulses for each module to achieve an adequately low sparking rate. This contribution outlines the commissioning procedure, presents the sparking rate improvements and the radiation level improvements through the commissioning process and disc the near-online commissioning plans for this accelerator.
Date: December 1, 1992
Creator: Kroc, T.; Moretti, A. & Popovic, M.
Partner: UNT Libraries Government Documents Department

Fermilab Linac Upgrade: Module conditioning results

Description: The 805 MHz Side-coupled cavity modules for the Fermilab 400 MeV linac upgrade have been conditioned to accept full power. The sparking rate in the cavities and in the side-cells has been reduced to acceptable levels. It required approximately 40 {times} 10{sup 6} pulses for each module to achieve an adequately low sparking rate. This contribution outlines the commissioning procedure, presents the sparking rate improvements and the radiation level improvements through the commissioning process and disc the near-online commissioning plans for this accelerator.
Date: December 1, 1992
Creator: Kroc, T.; Moretti, A. & Popovic, M.
Partner: UNT Libraries Government Documents Department

Operation and performance of the new Fermilab Booster H- injection system

Description: The operation and performance of the new, 15 Hz, H{sup -} charge exchange injection system for the FNAL Booster is described. The new system installed in 2006 was necessary to allow injection into the Booster at up to 15 Hz. It was built using radiation hardened materials which will allow the Booster to reliably meet the high intensity and repetition rate requirements of the Fermilab's HEP program. The new design uses three orbit bump magnets (Orbumps) rather than the usual four and permits injection into the Booster without a septum magnet. Injection beam line modification and compensation for the quadrupole gradients of the Orbump magnets is discussed.
Date: June 1, 2007
Creator: Lackey, J.; Garcia, F.G.; Popovic, M.; Prebys, E. & /Fermilab
Partner: UNT Libraries Government Documents Department

Continued Conditioning of the Fermilab 400 MeV linac high-gradient side-couple cavities

Description: The high energy portion of the Fermilab 400 MeV Linac is made of high gradient (37 MV/meter surface field) side-coupled cavity section which were conditioned over a 10 month period before their installation in August of 1993. We have continued to monitor the conditioning of these cavities since that time while the cavities have been operation, and those results are presented here. The sparking rate and the X-ray production are measured and compared with the 1992/1993 pre-operational and 1993/1994 early operational measurements. These rates are consistent with a continued diminishing of these phenomena. Predictions and spark management strategies presented in earlier reports are evaluated in light of present experiences. We also have been measuring the sparking rate within this structure with and without our 50 mA peak beam. We find that the sparking rate is 20% higher with beam in the accelerator.
Date: August 1, 1996
Creator: Kroc, T.; McCrory, E.; Moretti, A. & Popovic, M.
Partner: UNT Libraries Government Documents Department

1-GeV Linac Upgrade Study at Fermilab

Description: A linac injector for a new proton source complex at Fermilab is assumed to have a kinetic energy of 1 GeV. This linac would be sized to accelerate 100 mA of H{sup -} beam in a 200 microsecond pulse at a 15 Hz repetition rate. This would be adequate to produce {approximately}10{sup 14} protons per pulse allowing for future improvements of the new proton source complex. An alternate proposal is to add 600 MeV of side coupled cavity linac at 805 MHz to the existing 400 MeV Linac. This addition may either be in a new location or use the present Booster tunnel. A discussion of these possibilities will be given.
Date: September 1998
Creator: Popovic, M.; Moretti, A.; Noble, R. & Schmidt, C. W.
Partner: UNT Libraries Government Documents Department

Operation and improvements of the Fermilab 400 MeV Linac

Description: The 400 MeV Fermilab Linac Upgrade commissioning began August 28, 1993. High energy physics collider operation (run 1b) began in November 1993 and ended March 1, 1996. The Linac, operating at 98% reliability, provided 400 MeV H{sup -} beam to the Booster and 66 MeV H{sup -} beam to the Neutron Therapy Facility. During this time, the beam intensity, which initially was administratively set to 35 MA, rose to a peak of 50 mA while losses decreased significantly. This paper discusses the Linac operation and reliability since the Upgrade.
Date: September 1, 1996
Creator: Allen, L.J.; Popovic, M. & Schmidt, C.W.
Partner: UNT Libraries Government Documents Department

Emittance measurement techniques used in the 1 MeV RFQ for the PET isotope linac at Fermilab

Description: Beam emittance measurements have been performed on the {sup 3}He{sup +} beam at the PET isotope production accelerator, being commissioned at Fermilab for the Biomedical Research Foundation in Shreveport, Louisiana, USA. Emittances have been measured at injection to and extraction from the first RFQ, at 20 keV and 1 MeV, respectively. A single slit followed by a 48 electrode collector is used in the standard way to measure the divergence of the {sup 3}He{sup +} beam as a function of position. Noise reduction operations have been developed, both in hardware and software. These techniques and the emittance measurement results are presented.
Date: September 1, 1996
Creator: McCrory, E.; Popovic, M.; Schmidt, C.W. & Young, P.
Partner: UNT Libraries Government Documents Department

Longitudinal emittance from the Fermilab 400 MeV Linac

Description: The measurements which characterize the longitudinal emittance of the Fermilab 400 MeV Linac beam are presented. These measurements are made by determining the momentum spread and the bunch length of the beam using wall-current monitors, bunch length detectors and a spectrometer.
Date: September 1, 1996
Creator: McCrory, E.; Allen, L.; Popovic, M. & Schmidt, C.W.
Partner: UNT Libraries Government Documents Department

The radiation environment in and near high gradient rf cavities.

Description: The radiation environment in and near high gradient rf cavities is very important for the instrumentation of the MUCOOL experiment, since large fluxes of x rays and dark current electrons can interfere with the operation of the muon detectors. We have measured the x ray and dark current spectra from a single cell, 1.3 GHz, and are beginning to make more extensive measurements of a multicelled 805 MHz cavity. The results are consistent with electron field emission, bremsstrahlung and photon absorption/scattering. We discuss ways of minimizing this background and the scaling of these results to other cavities.
Date: July 23, 2001
Creator: Ducas, L.; Norem, J.; Geer, S.; Moretti, A.; Popovic, M. & Solomey, N.
Partner: UNT Libraries Government Documents Department

Duoplasmatron source modifications for {sup 3}He{sup +} Operation

Description: A duoplasmatron ion source is used to produce 25 mA of {sup 3}He+ with a pulse width of {approximately}80 ms at 360 Hz for acceleration to 10.5 MeV. At this energy, {sup 3}He striking water or carbon targets can produce short lived isotopes of {sup 11}C, {sup 13}N, {sup 15}O and {sup 18}F for medical positron emission tomography (PET). A duoplasmatron ion source was chosen originally since it is capable of a sufficient singly-charged helium beam with an acceptable gas consumption. Stable long-term operation of the source required a change in the filament material to molybdenum, and a careful understanding of the oxide filament conditioning, operation and geometry. Other improvements, particularly in the electronics, were helpful to increasing the reliability. The source has operated for many months at {approximately}2.5% duty factor without significant problems and with good stability. We report here the effort that was done to make this source understandable and reliable.
Date: November 1, 1997
Creator: Schmidt, C.W. & Popovic, M.
Partner: UNT Libraries Government Documents Department

Performance and measurements of the Fermilab Booster

Description: We will describe measurements of the beam in the Fermilab Booster during the first five milliseconds. Most of the particle losses in the Booster are over after the first few milliseconds. At high intensity of 4 x 10{sup 12} the transmission is 75%. Such high beam loss can be a limiting factor for future high repetition rate operation of the Booster. The evidence, although indirect, suggests that the losses are the result of incoherent space-charge effects at low energy.
Date: June 1, 1998
Creator: Popovic, M. & Akenbrandt, C.
Partner: UNT Libraries Government Documents Department

Phase and Frequency Locked Magnetrons for SRF Sources

Description: Magnetrons are low-cost highly-efficient microwave sources, but they have several limitations, primarily centered about the phase and frequency stability of their output. When the stability requirements are low, such as for medical accelerators or kitchen ovens, magnetrons are the very efficient power source of choice. But for high energy accelerators, because of the need for frequency and phase stability - proton accelerators need 1-2 degrees source phase stability, and electron accelerators need .1-.2 degrees of phase stability - they have rarely been used. We describe a novel variable frequency cavity technique which will be utilized to phase and frequency lock magnetrons.
Date: May 1, 2009
Creator: Neubauer, M.; Johnson, R.P.; /Muons Inc., Batavia; Popovic, M.; Moretti, A. & /Fermilab
Partner: UNT Libraries Government Documents Department

Preparations for Muon Experiments at Fermilab

Description: The use of existing Fermilab facilities to provide beams for two muon experiments--the Muon to Electron Conversion Experiment (Mu2e) and the New g-2 Experiment--is under consideration. Plans are being pursued to perform these experiments following the completion of the Tevatron Collider Run II, utilizing the beam lines and storage rings used today for antiproton accumulation without considerable reconfiguration.
Date: May 1, 2009
Creator: Syphers, M.J.; Popovic, M.; Prebys, E.; /Fermilab; Ankenbrandt, C. & /Muons Inc., Batavia
Partner: UNT Libraries Government Documents Department

Design Concept for nu-STORM: An Initial Very Low-Energy Neutrino Factory

Description: We present a design concept for a {nu} source from a STORage ring for Muons ({nu}STORM). In this initial design a high-intensity proton beam produces {approx}5 GeV pions that provide muons that are captured using 'stochastic injection' within a 3.6 GeV racetrack storage ring. In 'stochastic injection', the {approx}5 GeV pion beam is transported from the target into the storage ring, dispersion-matched into a long straight section. (Circulating and injection orbits are separated by momentum.) Decays within that straight section provide muons that are within the {approx}3.6 GeV/c ring momentum acceptance and are stored for the muon lifetime of {approx}1000 turns. Muon (and pion) decays in the long straight sections provide neutrino beams of precisely known flux and flavor that can be used for precision measurements of electron and muon neutrino interactions, and neutrino oscillations or disappearance at L/E = {approx}1m/MeV. The facility is described, and variations are discussed.
Date: May 1, 2012
Creator: Bross, A.; Geer, S.; Liu, A.; Neuffer, D.; Popovic, M.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Using the Fermilab proton source for a muon to electron conversion experiment

Description: The Fermilab proton source is capable of providing 8 GeV protons for both the future long-baseline neutrino program (NuMI), and for a new program of low energy muon experiments. In particular, if the 8 GeV protons are rebunched and then slowly extracted into an external beamline, the resulting proton beam would be suitable for a muon-to-electron conversion experiment designed to improve on the existing sensitivity by three orders of magnitude. We describe a scheme for the required beam manipulations. The scheme uses the Accumulator for momentum stacking, and the Debuncher for bunching and slow extraction. This would permit simultaneous operation of the muon program with the future NuMI program, delivering 10{sup 20} protons per year at 8 GeV for the muon program at the cost of a modest ({approx}10%) reduction in the protons available to the neutrino program.
Date: November 1, 2006
Creator: Ankenbrandt, C.; Bogert, D.; DeJongh, F.; Geer, S.; McGinnis, D.; Neuffer, D. et al.
Partner: UNT Libraries Government Documents Department

Traveling Wave RF Systems for Helical Cooling Channels

Description: The great advantage of the helical ionization cooling channel (HCC) is its compact structure that enables the fast cooling of muon beam 6-dimensional phase space. This compact aspect requires a high average RF gradient, with few places that do not have cavities. Also, the muon beam is diffuse and requires an RF system with large transverse and longitudinal acceptance. A traveling wave system can address these requirements. First, the number of RF power coupling ports can be significantly reduced compared with our previous pillbox concept. Secondly, by adding a nose on the cell iris, the presence of thin metal foils traversed by the muons can possibly be avoided. We show simulations of the cooling performance of a traveling wave RF system in a HCC, including cavity geometries with inter-cell RF power couplers needed for power propagation.
Date: May 1, 2009
Creator: Yonehara, K.; Lunin, A.; Moretti, A.; Popovic, M.; Romanov, G.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Low-energy neutrino factory design

Description: The design of a low-energy (4 GeV) neutrino factory (NF) is described, along with its expected performance. The neutrino factory uses a high-energy proton beam to produce charged pions. The {pi}{sup {+-}} decay to produce muons ({mu}{sup {+-}}), which are collected, accelerated, and stored in a ring with long straight sections. Muons decaying in the straight sections produce neutrino beams. The scheme is based on previous designs for higher energy neutrino factories, but has an improved bunching and phase rotation system, and new acceleration, storage ring, and detector schemes tailored to the needs of the lower energy facility. Our simulations suggest that the NF scheme we describe can produce neutrino beams generated by {approx} 1.4 x 10{sup 21} {mu}{sup +} per year decaying in a long straight section of the storage ring, and a similar number of {mu}{sup -} decays.
Date: July 1, 2009
Creator: Ankenbrandt, C.; /Fermilab /MUONS Inc., Batavia; Bogacz, S.A.; Lab, /Jefferson; Bross, A.; Geer, S. et al.
Partner: UNT Libraries Government Documents Department

A proton driver for the muon collider source with a tunable momentum compaction lattice

Description: The future Muon Collider will have a luminosity of the order of 10{sup 35} cm{sup {minus}2{minus}1} during 1,000 turns when the muons decay. This requires 10{sup 12} muons per bunch. The muon source is a 30 GeV proton driver with 2.5 10{sup 13} protons per pulse. The proton bunch length should be of the order of 1 ns. Short bunches could be created by a tunable momentum compaction lattice which would bring the momentum compaction to zero in a short time. This isochronous conduction would allow bunches to shear and become very short in time. The authors present a lattice where the momentum compaction is a tunable parameter at fixed horizontal and vertical betatron tunes. The values of the maxima of the dispersion function are kept small. They examine two kinds of lattices, with combined function as well as normal dipole and quadrupole magnets.
Date: July 1, 1997
Creator: Trbojevic, D.; Brennan, J.M.; Courant, E.D.; Roser, T.; Peggs, S.; Ng, K.Y. et al.
Partner: UNT Libraries Government Documents Department

Influence of Intense Beam in High Pressure Hydrogen Gas Filled RF Cavities

Description: The influence of an intense beam in a high-pressure gas filled RF cavity has been measured by using a 400 MeV proton beam in the Mucool Test Area at Fermilab. The ionization process generates dense plasma in the cavity and the resultant power loss to the plasma is determined by measuring the cavity voltage on a sampling oscilloscope. The energy loss has been observed with various peak RF field gradients (E), gas pressures (p), and beam intensities in nitrogen and hydrogen gases. Observed RF energy dissipation in single electron (dw) in N{sub 2} and H{sub 2} gases was 2 10{sup -17} and 3 10{sup -17} Joules/RF cycle at E/p = 8 V/cm/Torr, respectively. More detailed dw measurement have been done in H{sub 2} gas at three different gas pressures. There is a clear discrepancy between the observed dw and analytical one. The discrepancy may be due to the gas density effect that has already been observed in various experiments.
Date: May 1, 2012
Creator: Yonehara, K.; Chung, M.; Collura, M.G.; Jana, M.R.; Leonova, M.; Moretti, A. et al.
Partner: UNT Libraries Government Documents Department

Doped H(2)-Filled RF Cavities for Muon Beam Cooling

Description: RF cavities pressurized with hydrogen gas may provide effective muon beam ionization cooling needed for muon colliders. Recent 805 MHz test cell studies reported below include the first use of SF{sub 6} dopant to reduce the effects of the electrons that will be produced by the ionization cooling process in hydrogen or helium. Measurements of maximum gradient in the Paschen region are compared to a simulation model for a 0.01% SF{sub 6} doping of hydrogen. The observed good agreement of the model with the measurements is a prerequisite to the investigation of other dopants.
Date: May 1, 2009
Creator: Yonehara, K.; Chung, M.; Jansson, A.; Hu, M.; Moretti, A.; Popovic, M. et al.
Partner: UNT Libraries Government Documents Department

Isochronous pion decay channel for enhanced muon capture

Description: Intense muon beams have many potential applications, including neutrino factories and muon colliders. However, muons are produced in tertiary beams into a diffuse phase space. To make useful beams, the muons must be rapidly cooled before they decay. A promising new concept for the collection and cooling of muon beams is being investigated, namely, the use of a nearly Isochronous Helical Transport Channel (IHTC) to facilitate capture of muons into RF bunches. Such a distribution could be cooled quickly and coalesced into a single bunch to optimize the luminosity of a muon collider. We describe the IHTC and provide simulations demonstrating isochronicity, even in the absence of RF and absorber.
Date: June 1, 2008
Creator: Yoshikawa, C.; Ankenbrandt, C.; Neuffer, D.; Popovic, M.; Yonehara, K.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department