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Design, Installation, and Initial Commissioning of the MTA Beamline

Description: A new experimental area designed to develop, test and verify muon ionization cooling apparatus using the 400-MeV Fermilab Linac proton beam has been fully installed and is presently being commissioned. Initially, this area was used for cryogenic tests of liquid-hydrogen absorbers for the MUCOOL R&D program and, now, for high-power beam tests of absorbers, high-gradient rf cavities in the presence of magnetic fields (including gas-filled cavities), and other prototype muon-cooling apparatus. The experimental scenarios being developed for muon facilities involve collection, capture, and cooling of large-emittance, high-intensity muon beams--{approx}10{sup 13} muons, so that conclusive tests of the apparatus require full Linac beam, which is 1.6 x 10{sup 13} p/pulse. To support the muon cooling facility, this new primary beamline extracts and transports beam directly from the Linac to the test facility. The design concept for the MuCool facility is taken from an earlier proposal [1], but modifications were necessary to accommodate high-intensity beam, cryogenics, and the increased scale of the cooling experiments. Further, the line incorporates a specialized section and utilizes a different mode of operation to provide precision measurements of Linac beam parameters. This paper reports on the technical details of the MuCool beamline for both modes.
Date: May 1, 2010
Creator: Moore, Craig; /Fermilab; Anderson, John; /Fermilab; Garcia, Fernanda; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Final Results on RF and Wake Kicks Caused by the Couplers for the ILC Cavity

Description: In the paper the results are presented for calculation of the transverse wake and RF kick from the power and HOM couplers of the ILC acceleration structure. The RF kick was calculated stand-alone by HFSS, CST MWS and COMSOL codes while the wake kick was calculated by GdfidL. The calculation precision and convergence for both cases are discussed and compared to the results obtained independently by other group.
Date: May 1, 2010
Creator: Lunin, Andrei; /Fermilab; Gonin, Ivan; /Fermilab; Solyak, Nikolay; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Dynamics of Flat Bunches with Second Harmonic RF

Description: We investigate the dynamics of longitudinally flat bunches created with a second harmonic cavity in a high energy collider. We study Landau damping in a second harmonic cavity with analytical and numerical methods. The latter include particle tracking and evolution of the phase space density. The results are interpreted in the context of possible application to the LHC. A possible path to a luminosity upgrade at the LHC is through the creation of longitudinally flat bunches. They can increase the luminosity roughly by 40% when the beam intensities are at the beam-beam limit. Lower momentum spread which can reduce backgrounds and make collimation easier as well lower peak fields which can mitigate electron cloud effects are other advantages. Use of a second harmonic rf system is a frequently studied method to create such flat bunches. Here we consider some aspects of longitudinal dynamics of these bunches in the LHC at top energy. First we consider intensity limits set by the loss of Landau damping against rigid dipole oscillations. Next we describe numerical simulations using both particle tracking and evolution of the phase space density. These simulations address the consequences of driving a bunch at a frequency that corresponds to the maximum of the synchrotron frequency.
Date: May 1, 2010
Creator: Sen, Tanaji; /Fermilab; Bhat, Chandra; /Fermilab; Kim, Hyung Jin; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

IBS in a CAM-Dominated Electron Beam

Description: We report on the performance and planned upgrades to the Fermilab Accumulator Stacktail Stochastic Cooling System. The current system has achieved a maximum flux of 16.5e10/hour, limited by the input flux of antiprotons. The upgrades are designed to handle flux in excess of 40e10/hour.
Date: December 1, 2005
Creator: Burov, Alexey V.; /Fermilab; Gusachenko, I.; U., /Novosibirsk State; Nagaitsev, S.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Model for Initiation of Quality Factor Degradation at High Accelerating Fields in Superconducting Radio-Frequency Cavaties

Description: A model for the onset of the reduction in SRF cavity quality factor, the so-called Q-drop, at high accelerating electric fields is presented. Since magnetic fields at the cavity equator are tied to accelerating electric fields by a simple geometric factor, the onset of magnetic flux penetration determines the onset of Q-drop. We consider breakdown of the surface barrier at triangular grooves to predict the magnetic field of first flux penetration H{sub pen}. Such defects were argued to be the worst case by Buzdin and Daumens, [1998 Physica C 294 257], whose approach, moreover, incorporates both the geometry of the groove and local contamination via the Ginzburg-Landau parameter {kappa}. Since previous Q-drop models focused on either topography or contamination alone, the proposed model allows new comparisons of one effect in relation to the other. The model predicts equivalent reduction of H{sub pen} when either roughness or contamination were varied alone, so smooth but dirty surfaces limit cavity performance about as much as rough but clean surfaces do. Still lower H{sub pen} was predicted when both effects were combined, i.e. contamination should exacerbate the negative effects of roughness and vice-versa. To test the model with actual data, coupons were prepared by buffered chemical polishing and electropolishing, and stylus profilometry was used to obtain distributions of angles. From these data, curves for surface resistance generated by simple flux flow as a function of magnetic field were generated by integrating over the distribution of angles for reasonable values of {kappa}. This showed that combined effects of roughness and contamination indeed reduce the Q-drop onset field by {approx}20%, and that that contamination contributes to Q-drop as much as roughness. The latter point may be overlooked by SRF cavity research, since access to the cavity interior by spectroscopy tools is very difficult, whereas optical images ...
Date: July 13, 2010
Creator: Dzyuba, A.; U., /Fermilab /Novosibirsk State; Romanenko, A.; /Fermilab; Cooley, L.D. & /Fermilab
Partner: UNT Libraries Government Documents Department

VME Data Acquisition Modules for MINERvA Experiment

Description: This document describes two VME modules developed for MINERvA experiment at Fermilab. The Chain ReadOut Controller (CROC) module has four serial data channels and can interface with up to 48 front-ends using standard CAT5e networking cable. The data transmission rate of each channel is 160 Mbit/s. The maximum data transmission rate via VME bus is {approx}18 MB/s. The Chain Readout Interface Module (CRIM) is designed to provide various interface functions for the CROC module. It is compatible with MINOS MTM timing module and can be used to distribute timing signals to four CROC modules. The CRIM module also has a data port compatible with the CROC serial data interface. The data port can be used for diagnostic purpose and can generate triggers from front-end events. The CRIM module is a standard D08(O) interrupter module.
Date: January 1, 2010
Creator: Baldin, B. & /fermilab
Partner: UNT Libraries Government Documents Department

Fermilab Steering Group Report

Description: The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOvA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building an intense proton facility, Project X, consisting of a linear accelerator with the currently planned characteristics of the ILC combined with Fermilab's existing Recycler Ring and the Main Injector accelerator. The major component of Project X is the linac. Cryomodules, radio-frequency distribution, cryogenics and instrumentation for the linac are the same as or similar to those used in the ILC at a scale of about one percent of a full ILC linac. Project X's intense proton beams would open a path to discovery in neutrino science and in precision physics with charged leptons and quarks. World-leading experiments would allow physicists to address key questions of the Quantum Universe: How did the universe come to be? Are there undiscovered principles of nature: new symmetries, new physical laws? Do all the particles and forces become one? What happened to the antimatter? Building Project X's ILC-like linac would offer substantial support for ILC ...
Date: December 1, 2007
Creator: Steering Group, Fermilab
Partner: UNT Libraries Government Documents Department

What can gamma ray bursts teach us about dark energy?

Description: It has been suggested that Gamma Ray Bursts (GRB) may enable the expansion rate of our Universe to be measured out to very high redshifts (z {approx}> 5) just as type Ia supernovae have done at z {approx} 1-1.5. We explore this possibility here, and find that GRB have the potential to detect dark energy at high statistical significance, but they are unlikely to be competitive with future supernovae missions, such as SNAP, in measuring the properties of the dark energy. The exception to this conclusion is if there is appreciable dark energy at early times, in which case the information from GRB's will provide an excellent complement to the z {approx} 1 information from supernovae.
Date: December 1, 2005
Creator: Hooper, Dan; /Fermilab; Dodelson, Scott & /Fermilab /Chicago U., Astron. Astrophys. Ctr.
Partner: UNT Libraries Government Documents Department

New states above charm threshold

Description: We revise and extend expectations for the properties of charmonium states that lie above charm threshold, in light of new experimental information. We refine the Cornell coupled-channel model for the coupling of c{bar c} levels to two-meson states, defining resonance masses and widths by pole positions in the complex energy plane, and suggest new targets for experiment.
Date: November 1, 2005
Creator: Eichten, Estia J.; /Fermilab; Lane, Kenneth; U., /Boston; Quigg, Chris & /Fermilab
Partner: UNT Libraries Government Documents Department

Plans for a 750 MeV electron beam test facility at Fermilab

Description: A 750 MeV electron beam test facility at Fermilab is in the planning and early construction phase. An existing building is being converted for this facility. The photoinjector currently in use at the Fermilab NICADD Photoinjector Laboratory (FNPL) will be moved to the new facility and upgraded to serve as an injector for a beam acceleration section consisting of three TTF or ILC-type RF cryomodules. A low energy off-axis beamline will be constructed to test ILC crab cavity designs and provide opportunities for other tests. Downstream beamlines will consist of a diagnostic section, a beam test area for additional beam experiments, and high power beam dumps. The initial program for this facility will concentrate on testing ILC-type cryomodules and RF control with full ILC beam intensity. A future building expansion will open up further possibilities for beam physics and beam technology experiments.
Date: June 1, 2007
Creator: Church, M.; Nagaitsev, S.; /Fermilab; Piot, P. & U., /Fermilab /Northern Illinois
Partner: UNT Libraries Government Documents Department

Status of the ATF Damping Ring BPM Upgrade Project

Description: A substantial upgrade of the beam position monitors (BPM) at the ATF (Accelerator Test Facility) damping ring is currently in progress. Implementing digital read-out signal processing techniques in line with an optimized, low-noise analog downconverter, a resolution well below 1 mum could be demonstrated at 20 (of 96) upgraded BPM stations. The narrowband, high resolution BPM mode permits investigation of all types of non-linearities, imperfections and other obstacles in the machine which may limit the very low target aimed vertical beam emittance of < 2 pm. The technical status of the project, first beam measurements and an outlook to it's finalization are presented.
Date: December 1, 2011
Creator: Briegel, C.; /Fermilab; Eddy, N.; /Fermilab; Haynes, B.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Self-accelerating Warped Braneworlds

Description: Braneworld models with induced gravity have the potential to replace dark energy as the explanation for the current accelerating expansion of the Universe. The original model of Dvali, Gabadadze and Porrati (DGP) demonstrated the existence of a ''self-accelerating'' branch of background solutions, but suffered from the presence of ghosts. We present a new large class of braneworld models which generalize the DGP model. Our models have negative curvature in the bulk, allow a second brane, and have general brane tensions and localized curvature terms. We exhibit three different kinds of ghosts, associated to the graviton zero mode, the radion, and the longitudinal components of massive graviton modes. The latter two species occur in the DGP model, for negative and positive brane tension respectively. In our models, we find that the two kinds of DGP ghosts are tightly correlated with each other, but are not always linked to the feature of self-acceleration. Our models are a promising laboratory for understanding the origins and physical meaning of braneworld ghosts, and perhaps for eliminating them altogether.
Date: November 1, 2006
Creator: Carena, Marcela; Lykken, Joseph; /Fermilab; Park, Minjoon; /UC, Davis; Santiago, Jose et al.
Partner: UNT Libraries Government Documents Department

The modeling of RF stacking of protons in the Accumulator

Description: When the Run2 collider program is terminated in 2009, the present pbar source will be available for other usages. One possible application is to convert the Antiproton Accumulator to a proton accumulator so that the beam power from the Main Injector could be greatly enhanced [1]. The Accumulator has the unique feature of very large momentum acceptance. It is possible to stack 3-4 Booster batches in the longitudinal phase space before transferring them to the Main Injector or Recycler. This note shows the simulation of RF stacking using the code ESME [2].
Date: June 1, 2005
Creator: Yoon, Phil S.; U., /Fermilab /Rochester; McGinnis, David P.; Chou, Weiren & /Fermilab
Partner: UNT Libraries Government Documents Department

Efficiency and lifetime of carbon foils

Description: Charge-exchange injection by means of carbon foils is a widely used method in accelerators. This paper discusses two critical issues concerning the use of carbon foils: efficiency and lifetime. An energy scaling of stripping efficiency was suggested and compared with measurements. Several factors that determine the foil lifetime--energy deposition, heating, stress and buckling--were studied by using the simulation codes MARS and ANSYS.
Date: November 1, 2006
Creator: Chou, W.; /Fermilab; Kostin, M.; /Michigan State U., NSCL; Tang, Z. & /Fermilab
Partner: UNT Libraries Government Documents Department

Generation of femtosecond bunch trains using a longitudinal-to-transverse phase space exchange technique

Description: We demonstrate analytically and via numerical simulations, how a longitudinal-to-transverse phase space manipulation can be used to produce a train of femtosecond electron bunches. The technique uses an incoming transversely-modulated electron beam obtained via destructive (e.g. using a multislits mask) methods. A transverse-to-longitudinal exchanger is used to map this transverse modulation into a temporal modulation. Limitation of the proposed method and scalability to the femtosecond regime are analyzed analytically and with the help of numerical simulation. Finally, a proof-of-principle experiment is discussed in the context of the Fermilab's A0 photoinjector.
Date: October 1, 2008
Creator: Sun, Yin-e; /Fermilab; Piot, Philippe & U., /Fermilab /Northern Illinois
Partner: UNT Libraries Government Documents Department

CDF GlideinWMS usage in grid computing of high energy physics

Description: Many members of large science collaborations already have specialized grids available to advance their research in the need of getting more computing resources for data analysis. This has forced the Collider Detector at Fermilab (CDF) collaboration to move beyond the usage of dedicated resources and start exploiting Grid resources. Nowadays, CDF experiment is increasingly relying on glidein-based computing pools for data reconstruction. Especially, Monte Carlo production and user data analysis, serving over 400 users by central analysis farm middleware (CAF) on the top of Condor batch system and CDF Grid infrastructure. Condor is designed as distributed architecture and its glidein mechanism of pilot jobs is ideal for abstracting the Grid computing by making a virtual private computing pool. We would like to present the first production use of the generic pilot-based Workload Management System (glideinWMS), which is an implementation of the pilot mechanism based on the Condor distributed infrastructure. CDF Grid computing uses glideinWMS for its data reconstruction on the FNAL campus Grid, user analysis and Monte Carlo production across Open Science Grid (OSG). We review this computing model and setup used including CDF specific configuration within the glideinWMS system which provides powerful scalability and makes Grid computing working like in a local batch environment with ability to handle more than 10000 running jobs at a time.
Date: January 1, 2010
Creator: Zvada, Marian; /Fermilab /Kosice, IEF; Benjamin, Doug; U., /Duke; Sfiligoi, Igor & /Fermilab
Partner: UNT Libraries Government Documents Department

Beam dynamics simulations of the NML photoinjector at Fermilab

Description: Fermilab is currently constructing a superconducting RF (SRF) test linear accelerator at the New Muon Lab (NML). Besides testing SRF accelerating modules for ILC and Project-X, NML will also eventually support a variety of advanced accelerator R&D experiments. The NML incorporates a 40 MeV photoinjector capable of providing electron bunches with variable parameters. The photoinjector is based on the 1+1/2 cell DESY-type gun followed by two superconducting cavities. It also includes a magnetic bunch compressor, a round-to-flat beam transformer and a low-energy experimental area for beam physics experiments and beam diagnostics R&D. In this paper, we explore, via beam dynamics simulations, the performance of the photoinjector for different operating scenarios.
Date: August 1, 2010
Creator: Piot, P.; U., /Fermilab /Northern Illinois; Sun, Y.-E.; Church, M. & /Fermilab
Partner: UNT Libraries Government Documents Department

Subpicosecond electron bunch train production using a phase-space exchange technique

Description: Our recent experimental demonstration of a photoinjector electron bunch train with sub-picosecond structures is reported in this paper. The experiment is accomplished by converting an initially horizontal beam intensity modulation into a longitudinal phase space modulation, via a beamline capable of exchanging phase-space coordinates between the horizontal and longitudinal degrees of freedom. The initial transverse modulation is produced by intercepting the beam with a multislit mask prior to the exchange. We also compare our experimental results with numerical simulations.
Date: March 1, 2011
Creator: Sun, Y.-E.; /Fermilab; Piot, P.; U., /Fermilab /Northern Illinois; Johnson, A.S.; Lumpkin, A.H. et al.
Partner: UNT Libraries Government Documents Department

Experimental generation of longitudinally-modulated electron beams using an emittance exchange technique

Description: We report our experimental demonstration of longitudinal phase space modulation using a transverse-to-longitudinal emittance exchange technique. The experiment is carried out at the A0 photoinjector at Fermi National Accelerator Lab. A vertical multi-slit plate is inserted into the beamline prior to the emittance exchange, thus introducing beam horizontal profile modulation. After the emittance exchange, the longitudinal phase space coordinates (energy and time structures) of the beam are modulated accordingly. This is a clear demonstration of the transverse-to-longitudinal phase space exchange. In this paper, we present our experimental results on the measurement of energy profile as well as numerical simulations of the experiment.
Date: August 1, 2010
Creator: Sun, Y.-E; /FERMILAB; Piot, P.; U., /FERMILAB /Northern Illinois; Johnson, A.; Lumpkin, A. et al.
Partner: UNT Libraries Government Documents Department

Tunable subpicosecond electron bunch train generation using a transverse-to-longitudinal phase space exchange technique

Description: We report on the experimental generation of a train of subpicosecond electron bunches. The bunch train generation is accomplished using a beamline capable of exchanging the coordinates between the horizontal and longitudinal degrees of freedom. An initial beam consisting of a set of horizontally-separated beamlets is converted into a train of bunches temporally separated with tunable bunch duration and separation. The experiment reported in this Letter unambiguously demonstrates the conversion process and its versatility.
Date: November 1, 2010
Creator: Sun, Y.-E; /Fermilab; Piot, P.; Johnson, A.; U., /Fermilab /Northern Illinois; Lumpkin, A.H. et al.
Partner: UNT Libraries Government Documents Department

Transverse-to-longitudinal phase space exchange: a versatile tool for shaping the current and energy profiles of relativistic electron bunches

Description: Over the recent years, the emergence of accelerator beamlines capable of exchanging the phase space coordinates between two degrees of freedom have opened the path toward the precise control of phase space distribution and in particular to the production of relativistic electron beams with shaped current profiles. After briefly reviewing the technique, we present its application to produce a train of sub-picosecond microbunches and report on its experimental implementation at the Fermilab's A0 photoinjector facility.
Date: August 1, 2010
Creator: Piot, P.; /NICADD, DeKalb /Fermilab; Sun, Y.-E.; /Fermilab; Johnson, A.S.; Lumpkin, A.H. et al.
Partner: UNT Libraries Government Documents Department

Fermilab Steering Group Report

Description: The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOVA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building an intense proton facility, Project X, consisting of a linear accelerator with the currently planned characteristics of the ILC combined with Fermilab's existing Recycler Ring and the Main Injector accelerator. The major component of Project X is the linac. Cryomodules, radio-frequency distribution, cryogenics and instrumentation for the linac are the same as or similar to those used in the ILC at a scale of about one percent of a full ILC linac. Project X's intense proton beams would open a path to discovery in neutrino science and in precision physics with charged leptons and quarks. World-leading experiments would allow physicists to address key questions of the Quantum Universe: How did the universe come to be? Are there undiscovered principles of nature: new symmetries, new physical laws? Do all the particles and forces become one? What happened to the antimatter? Building Project X's ILC-like linac would offer substantial support for ILC ...
Date: January 1, 2007
Creator: Beier, Eugene; U., /Pennsylvania; Butler, Joel; /Fermilab; Dawson, Sally; /Brookhaven et al.
Partner: UNT Libraries Government Documents Department