| Paper | Title | Other Keywords | Page | ||
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| MOAA005 | FNAL Tevatron Operational Status | luminosity, proton, collider, electron | 484 | ||
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Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy. |
The Fermilab Tevatron Proton-Antiproton Collider is currently the world’s highest energy hadron collider. The luminosity of the Fermilab collider has been significantly increased with the Main Injector operating at its design goals. Further increases in luminosity have been the result of combining antiprotons from the Recycler and Accumulator storage rings. Recent commissioning of proton slip-stacking in the Main Injector has noticeably increased the antiproton accumulation rate. The increased stacking rate permits the sustained operation of using antiprotons from both the Accumulator and Recycler. Further increases in peak luminosity are expected from electron cooling in the Recycler and increased antiproton flux from the Antiproton Source. |
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| MOPA006 | Theory and Reality of Beam-Beam Effects at Hadron Colliders | resonance, proton, beam-beam-effects, emittance | 544 | ||
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The beam-beam phenomena in hadron colliders is just as rich as in e+e- machines: orbit and focusing perturbations, excitation of nonlinear resonances, coherent tuneshifts. Moreover, the absence of radiation damping and long duration of a store permit even high-order (and correspondingly weak) resonances to manifest themselves presenting a major challenge for both theoretical analysis and machine operation. The recent progress in understanding of and coping with the beam-beam effects at hadron colliders, primarily at the Tevatron, is discussed.
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| MPPE022 | Modification to the Lattice of the Fermilab Debuncher Ring To Improve the Performance of the Stochastic Cooling Systems | lattice, quadrupole, sextupole, injection | 1799 | ||
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Funding: Supported by the Department of Energy and the National Science Foundation. |
The Fermilab Debuncher is used to collect antiprotons from the production target, reduce the momentum spread of the beam by an RF bunch rotation, and stochastically cool the transverse and longitudinal emittances of the beam prior to transfer to the Accumulator. A large value of the slip factor of the ring lattice is favored to provide a larger momentum acceptance for the bunch rotation process, while a small value of the slip factor is desirable for stochastic cooling. A dynamic change in the lattice from a large slip factor at injection to a smaller slip factor at extraction would optimize both processes and could lead to an improvement in antiproton stacking rate. This paper discusses the details of lattice modifications to the Debuncher, achievable with the existing hardware, which would result in a 60% increase in the slip factor, while maintaining the tunes and chromaticities fixed, and keeping the betatron functions within an acceptable range. |
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| MPPE056 | Studies to Increase the Anti-Proton Transmission from the Target to the Debuncher Ring | lattice, sextupole, quadrupole, simulation | 3357 | ||
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Funding: This work was supported by the Director, Office of Science, High Energy Physics, U.S. Department of Energy under Contracts No. DE-AC03-76SF00098 and DE-AC02-76CH03000. |
The AP2 beamline at Fermilab transports anti-protons from the production target to the Debuncher ring. The measured admittance of the Debuncher ring and the theoretical aperture of the line are larger than the size of the transmitted beam. Extensive tracking studies were done using the Accelerator Toolbox (AT) to understand the sources of the difference. As simulations pointed to chromatic effects being a source of problems, measurements were done to study this. Several possible remedies were studied including adding sextupoles to the line to reduce the chromatic effects. |
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| MPPP002 | Stochastic Cooling Electrodes for a Wide Velocity Range in the CR | impedance, kicker, pick-up, coupling | 799 | ||
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The CR storage ring is part of the FAIR project at GSI. It serves as a first stage of stochastic cooling for secondary rare isotopes at v/c=0.83 as well as for antiprotons at v/c=0.97. To avoid the installation of dedicated structures for each kind of beam, electrodes have been developed which are usable for both beams. They are based on slotline structures mounted perpendicular to the beam. They are shorted at the ends, and their signal is extracted by two striplines on the rear side, placed a quarter wavelength away from the open ends. The width of the structures can be adjusted to the initial betatron oscillation amplitudes. Their length is 24 mm, and the signal from many of these structures mounted in a row can be combined. The signal combination can be matched to the different beam velocities. The paper shows results from field calculations, prototype tests, and estimates of the signal combination efficiency. The beam impedance of the novel structures is compared with the superelectrodes applied in the former CERN AC and with the slow-wave structures currently installed in the FNAL Debuncher.
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| MPPP015 | Operational Performance of a Bunch by Bunch Digital Damper in the Fermilab Main Injector | proton, damping, injection, diagnostics | 1440 | ||
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We have implemented a transverse and longitudinal bunch by bunch digital damper system in the Fermilab Main Injector, using a single digital board for all 3 coordinates. The system has been commissioned over the last year, and is now operational in all MI cycles, damping beam bunched at both 53MHz and 2.5MHz. We describe the performance of this system both for collider operations and high-intensity running for the NuMI project.
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| MPPP043 | Betatron Tune Spread Generation and Differential Chromaticity Control by Octupole at Tevatron | octupole, betatron, proton, injection | 2756 | ||
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Application of octupoles for Landau damping of the unstable head-tail modes requires careful consideration at their combination into separate families to insure maximum effectiveness and avoid degradation of the dynamic aperture due to the non-linear magnetic fields. Existing octupolar magnets around the machine have been arranged into four functional families with individual power supplies. Two of these families generate betatron tune spreads in the vertical and horizontal planes whereas the other two control the differential chromaticity between the proton and antiproton helices. The calculated effect on tunes and chromaticity is compared with direct measurements. Analytical formulas for betatron tune spectral density functions are presented.
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| MPPT056 | First Ideas Towards the Super-Conducting Magnet Design for the HESR at FAIR | dipole, quadrupole, magnet-design, sextupole | 3354 | ||
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The Forschungszentrum Juelich has taken the leadership of a consortium being responsible for the design of the HESR going to be part of the FAIR project at GSI. The HESR is a 50 Tm storage ring for antiprotons, based on a super-conducting magnet technology. On basis of the RHIC Dipole D0 (3.6 T), the magnet design for the HESR has started recently. One key issue will be a very compact layout because of the rather short magnets (been 1.82 m for the dipoles and 0.5 m for the other magnets). This paper will present first ideas of the magnetic and cryogenic layout, give a status report on the achievements so far and discuss the need and possible solutions for a bent magnet with a radius of curvature of 13.2 m.
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| TPAP026 | Improving the Tevatron Collision Helix | luminosity, emittance, proton, beam-beam-effects | 1931 | ||
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In the Tevatron, protons and pbars circulate in a single beam pipe, so electrostatic separators are used to create helical orbits that separate the two beams except at the two interaction points (IP). Increasing the separation outside of the IPs is desirable in order to decrease long range beam-beam effects during high energy physics (HEP) stores. We can increase separation by running the separators at higher gradients or by installing additional separators. We are pursuing both strategies in parallel. Here, we describe Tevatron operation with higher separator gradients and with new separators installed during a recent shutdown. We also describe possible future improvements.
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| TPAP031 | Simulations of an Acceleration Scheme for Producing High Intensity and Low Emittance Antiproton Beam for Fermilab Collider Operation | emittance, beam-loading, acceleration, simulation | 2164 | ||
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Funding: Operated by Universities Research Association, Inc. for the U.S. Department of Energy under contract DE-AC02-76CH03000. |
During Fermilab collider operation, the Main Injector (MI) provides high intensity and low emittance proton and antiproton beams for the Tevatron. The present coalescing scheme for antiprotons in the Main Injector yields about a factor of two increase in the longitudinal emittance and a factor of 5% to 20% decrease in intensity before injection to the Tevatron. In order to maximize the integrated luminosity delivered to the collider experiments, it is important to minimize the emittance growth and maximize the intensity of the MI beam. To this end, a new scheme* using a combination of 2.5 MHz and 53 MHz accelerations has been developed and tested. This paper describes the full simulation of the new acceleration scheme, taking account of space charge, 2.5 MHz and 53 MHz beam loading, and the effect of residual 53 MHz rf voltage during 2.5 MHz acceleration and rf manipulations. The simulations show the longitudinal emittance growth at the 10% level with no beam loss. The experimental test of the new scheme is reported in another PAC'05 paper. *G.P. Jackson, The Fermilab Recycler Ring Technical Design Report, FERMILAB-TM-1991, November 1996. |
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| TPAP032 | Beam-beam Effects in the Tevatron Run II | proton, emittance, luminosity, injection | 2245 | ||
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Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy. |
The Tevatron in Collider Run II (2001-present) is operating with many times higher beam intensities and luminosities than in previous Run I (1992-1995). Electromagnetic long-range and head-on interactions of high intensity proton and antiproton beams have been significant sources of beam loss and lifetime limitations. We present observations of the beam-beam phenomena in the Tevatron and results of relevant beam studies. We analyze the data and various methods employed in operations, predict the performance at upgraded beam parameters and luminosity and discuss possible improvements. |
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| TPAP033 | Tevatron Admittance Measurement | emittance, proton, kicker, betatron | 2306 | ||
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Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy. |
We measured the Tevatron Beam Acceptance by the method of exciting the beam emittance growth with the beam tickling system with noise. The noise power was about 3Watt with 100Hz bandwidth and centered either in horizontal betatron frequency or vertical betatron frequency. We were able to blow the beam emittance fast while under control. From the point the beam emittance stop growing, we measured the beam acceptance of the Tevatron. |
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| TPAP036 | Fitting the Luminosity Decay in the Tevatron | luminosity, proton | 2434 | ||
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Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
This paper explores the various ways in which the decay of the luminosity in the Tevatron have been fit. The standard assumptions of a fixed-lifetime exponential decay are only appropriate for very short time intervals. A "1/time" funcional form fits rather well, and is supported by analytical derivations. A more complex form, assuming a time-varying lifetime, produces excellent results. Changes in the luminosity can be factored into two phenomena: The luminosity burn-off rate, and the burn-off rate from non-luminosity effects. The luminous and the non-luminous burn rate are shown for stores in the Tevatron. |
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| TPAP037 | Monte Carlo of Tevatron Operations, Including the Recycler | luminosity, proton, emittance, electron | 2479 | ||
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Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
A Monte Carlo model, which was originally developed for "Run I" of the Tevatron Collider, has been enhanced in many ways, most notably, to incorporate the effect of the Recycler Ring. This model takes into account reasonable random fluctuations in the performance of the Collider, and normal interruptions in operation of each accelerator due to downtime. Optimization of the integrated luminosity delivered to the experiments is based on when to end the store and how to deal with the anitprotons. Preliminary results show that a 20% gain in integrated luminosity in the Collider results from using the Recycler for one-third of the anitprotons in each store. As electron cooling becomes operative in the Recycler, Collider performance improves by as much as a factor of two. |
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| TPAP038 | Characterizing Luminosity Evolution in the Tevatron | luminosity, proton, emittance, beam-beam-effects | 2536 | ||
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Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
We derive an approximate form of a luminosity evolution in a high intensity hadron collider taking into account the most important phenomena of intrabeam scattering (IBS), beam burn-up due to luminosity and beam-beam effects. It is well known that an exponential decay does not describe luminosity evolution very well unless the lifetime is allowed to vary with time. However, a "1/time" evolution, which this derivation shows is a good approximation, fits data from the Tevatron well. |
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| TPAP040 | Feasibility Study of Beam-Beam Compensation in the Tevatron with Wires | injection, simulation, beam-losses, lattice | 2645 | ||
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Funding: Dept. of Energy. |
At large distances the field profile of a current carrying wire matches the profile of the field of a round beam. We consider the practical applicability of this principle in compensating long-range beam-beam effects in the Tevatron. Changes in the helix and beam separation from injection energy to collision energy require that different wire configurations at these different energies. Due to the seventy or more long-range interactions, each set of wires must compensate several interactions. We first develop the principles of non-local compensation with a small set of wires. Next we use these principles in detailed simulation studies with beam-beam interactions and wire fields to determine the feasibility of the compensation in the Tevatron. |
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| TPAT072 | Long-Term Simulation of Beam-Beam Effects in the Tevatron at Collision Energy | simulation, lattice, coupling, beam-beam-effects | 3871 | ||
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The weak-strong beam-beam effect is expected substantially to contribute to the degradation of beam lifetimes in the Tevatron at collision energy. We have expanded an existing multi-processor code (which previously was applied to the Tevatron at injection energy* to include chromatic and non-linear lattice effects as well as a fully-coupled treatment of the lattice in different approximations.** We obtain lifetime predictions by doing temporal statistics on the tracking results of a weighted macroparticle distribution and fitting it to a class of solutions for the diffusion equation. We present typical results of parameter scans.
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*A. Kabel, Y. Cai, B. Erdelyi, T. Sen, M. Xiao; Proceedings of PAC03. **A. Kabel, this Conference. |
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| TPAT083 | Computational Study of the Beam-Beam Effect in Tevatron Using the LIFETRAC Code | luminosity, emittance, simulation, optics | 4117 | ||
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Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy. |
Results of a comprehensive numerical study of the beam-beam effect in the Tevatron are presented including the dependence of the luminosity lifetime on the tunes, chromaticity and optics errors. These results help to understand the antiproton emittance blow-up routinely observed in the Tevatron after the beams are brought into collision. To predict a long term luminosity evolution, the diffusion rates are increased to represent long operation time (~day) by using a small number of simulated turns. To justify this approach, a special simulation study of interplay between nonlinear beam-beam resonances and diffusion has been conducted. A number of ways to mitigate the beam-beam effects are discussed, such as increasing bunch spacing, separation between the beams and beam-beam compensation with electron lenses. |
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| TPAT084 | LIFETRAC Code for the Weak-Strong Simulation of the Beam-Beam Effect in Tevatron | betatron, simulation, optics, quadrupole | 4138 | ||
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Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy. |
A package of programs for weak-strong simulation of beam-beam effects in hadron colliders is described. Accelerator optics parameters relevant to the simulation are derived from beam measurements and calculations are made using OptiM optics code. The key part of the package is the upgraded version of the LIFETRAC code which now includes 2D coupled optics, chromatic modulation of beta-functions, non-Gaussian shape of the strong bunches and non-linear elements for beam-beam compensation. Parallel computations are used and in the case of the Tevatron (2 main IPs + 70 parasitic IPs) the code has a productivity of ~1·1010 particles*turns/day on a 32-node cluster of Pentium IV 1.8 GHz processors. |
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| TOAD002 | Novel Tune Diagnostics for the Tevatron | proton, pick-up, betatron, injection | 140 | ||
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The Tevatron collides protons and antiprotons in the same beam pipe. This poses a challenge in the measurement of tunes for both species simultanously because of the possibility of signal contamination from the other species. On top of this, since both beams are in the same beam pipe, tunes of individual bunches are also important because tune shifts from the beam-beam effect affects each bunch differently. Three different tune diagnostics used in the Tevatron will be discussed in this paper: 1.7GHz Schottky pickups, 21.4 MHz Schottky pickups and 27 kHz baseband pickups. These pickups look at the tune spectrum at different frequency bands and provide useful physics information for each frequency regime.
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| TOPC004 | Tevatron Beam Position Monitor Upgrade | pick-up, proton, injection, controls | 410 | ||
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Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
The Tevatron Beam Position Monitor (BPM) readout electronics and software have been upgraded to improve measurement precision, functionality and reliability. The original system, designed and built in the early 1980s, became inadequate for current and future operations of the Tevatron. The upgraded system consists of 960 channels of new electronics to process analog signals from 240 BPMs, new front-end software, new online and controls software, and modified applications to take advantage of the improved measurements and support the new functionality. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. Measurements using the new system are presented that demonstrate its improved resolution and overall performance. |
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| TPPE030 | A Method to Polarize Stored Antiprotons to a High Degree | electron, target, polarization, lattice | 2158 | ||
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The PAX collaboration proposes a method to produce intense beams of polarized antiprotons. Polarized antiprotons can be produced in a storage ring by spin-dependent interaction in a purely hydrogen gas target. The polarizing process is based on spin transfer from the polarized electrons of the target atoms to the orbiting antiprotons. After spin filtering for about two beam lifetimes at energies of about 50-100 MeV using a dedicated large acceptance ring, the antiproton polarization would reach P=0.2-0.4. In the presentation, beside a description of the polarization technique and its potentiality, a description of the ideal characterstics of the antiproton polarizer will be given.
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hep-ph/0411046 |
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| WPAE027 | Magnetic Shielding of an Electron Beamline in a Hadron Accelerator Enclosure | electron, shielding, dipole, quadrupole | 1997 | ||
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Funding: *Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
The Fermilab Electron Cooling Project requires the operation of a 4.35 MeV electron beam in the same enclosure that houses the 120 – 150 GeV Main Injector. Effective shielding of the magnetic fields from the ramped electrical buses and local static fields is necessary to maintain the high beam quality and recirculation efficiency required by the electron cooling system. This paper discusses the operational tolerances and the design of the beamline shielding, bus design, and bus shielding as well as experimental results from the prototype and final installation. |
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| WPAE029 | Tevatron Beam-beam Compensation Project Progress | electron, proton, gun, emittance | 2083 | ||
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Funding: Work supported by the Universities Research Assos., Inc., under contract DE-AC02-76CH03000 with the U.S. Dept. of Energy. |
The 2nd Tevatron electron lens (TEL2) is under the final phase of development and prepare for the installation in the Tevatron. In this report, we will describe the system and the main upgrades from the TEL1. We will also show the magnetic field measurement results, beam testing and plan for installation. The special operation consideration of the TEL2 under high radiation dose will also be discussed. |
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| RPAT009 | FPGA-Based Instrumentation for the Fermilab Antiproton Source | diagnostics, instrumentation, proton, controls | 1159 | ||
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We have designed and built low-cost, low-power, ethernet-based circuit boards to apply DSP techniques to several instrumentation upgrades in the Fermilab Antiproton Source. Commodity integrated circuits such as direct digital synthesizers, D/A and A/D converters, and quadrature demodulators enable digital manipulation of RF waveforms. A low cost FPGA implements a variety of signal processing algorithms in a manner that is easily adapted to new applications. An embedded microcontroller provides FPGA configuration, control of data acquisition, and command-line interface. A small commercial daughter board provides an ethernet-based TCP/IP interface between the microcontroller and the Fermilab accelerator control network. The board is packaged as a standard NIM module. Applications include Low Level RF control for the Debuncher, readout of transfer-line Beam Position Monitors, and narrow-band spectral analysis of diagnostic signals from Schottky pickups.
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| RPAT011 | Digital Signal Processing the Tevatron BPM Signals | pick-up, closed-orbit, proton, controls | 1242 | ||
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Funding: Fermilab |
The Beam Position Monitor (BPM) readout system at Fermilab’s Tevatron has been updated and is currently being commissioned. The new BPMs use new analog and digital hardware to achieve better beam position measurement resolution. The new system reads signals from both ends of the existing directional stripline pickups to provide simultaneous proton and antiproton position measurements. The signals provided by the two ends of the BPM pickups processed by analog band-pass filters and sampled by 14-bit ADCs at 74.3MHz. A crucial part of this work has been the design of digital filters that process the signal. This paper describes the digital processing and estimation techniques used to optimize the beam position measurement. The BPM electronics must operate in narrow-band and wide-band modes to enable measurements of closed-orbit and turn-by-turn positions. The filtering and timing conditions of the signals are tuned accordingly for the operational modes. The analysis and the optimized result for each mode is presented. |
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| RPAT013 | Signal Processing for Longitudinal Parameters of the Tevatron Beam | proton, emittance, pick-up, synchrotron | 1362 | ||
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Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
The time profiles of the bunches in the Tevatron are obtained by sampling the output of a resistive wall current monitor with a 5GS/s, 2GHz bandwidth, Lecroy 6200 oscilloscope. The techniques for removing the effect of cable dispersion and for extending the dynamic range of the data by splitting the signal and using two input channels at different gains are described. The algorithms for taking these data in the time domain and deriving the momentum spread and longitudinal emittance are also given. |
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| RPAT015 | First Results of a Digital Beam Phase Monitor at the Tevatron | proton, synchrotron, controls, injection | 1428 | ||
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A digital Beam Phase Monitor has been installed on the Tevatron ring. This device will be mainly use to diagnose the energy oscillations of each of the 36 × 36 protons and antiprotons bunches as well as to study the transient beam loading. The first results obtained from the Beam Phase Monitor will be presented on the paper.
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| RPAT017 | Using Time Separation of Signals to Obtain Independent Proton and Antiproton Beam Position Measurements Around the Tevatron | proton, acceleration, injection, closed-orbit | 1557 | ||
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Funding: Fermilab is operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
Independent position measurement of the counter-circulating proton and antiproton beams in the Tevatron presents a challenge to upgrading the Tevatron Beam Position Monitor (BPM) system. The inherent directionality of the Tevatron BPM pickup design provides 26dB isolation between signals from the two beams. At the present typical 10:1 proton-to-antiproton bunch intensity ratio, this isolation alone is insufficient to support millimeter accuracy antiproton beam position measurements due to interfering proton signals. An accurate and manageable solution to the interfering signal problem is required for antiproton measurements now and, as machine improvements lead to increased antiproton intensity, will facilitate future elimination of antiproton bias on proton beam position measurements. This paper discusses the possibilities and complications of using time separation of the two beam signals at the numerous Tevatron BPM locations and given the dynamic longitudinal conditions of Tevatron operation. Results of measurements results using one such method are presented. |
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| RPAT018 | Simultaneous Position Measurements of Protons and Anti-Protons in the Tevatron | injection, proton, pick-up, closed-orbit | 1613 | ||
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Fermilab has embarked upon a program to upgrade the electronics of the Beam Position Monitor (BPM) system that measures the transverse position of the beams inside the Tevatron collider. The new system improves on the current system in precision, accuracy and reliability. A new feature in the upgraded system is the ability, when both protons and anti-protons are present in the Tevatron, make simultaneous measurements of the closed orbit position of both beam species. The method chosen for achieving the simultaneous measurement is an algorithm that deconvolutes the imperfect directionality of the BPM pickups from the raw measurements. This paper will discuss the algorithm, the calibration of the parameters used by the algorithm and the robustness of the algorithm. It will also present results from the upgraded system which demonstrate that the system meets the requirements set out at the start of the upgrade project.
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| RPAT031 | Beam Profile Measurement with Flying Wires at the Fermilab Recycler Ring | emittance, lattice, vacuum, scattering | 2182 | ||
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The Fermilab Recycler Ring is a high vacuum fixed energy antiproton storage ring with stochastic and electron cooling systems. Flying wires were installed at the Fermilab Recycler Ring for transverse beam profile measurement. The following note describes the system configuration, calibration and resolution of the flying wire system, as well as analysis of the transverse beam profile in the presence of both cooling systems.
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| RPAT035 | Development of an Optical Transition Radiation Detector for Profile Monitoring of Antiproton and Proton Beams at FNAL | proton, target, radiation, injection | 2381 | ||
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Funding: Work Supported by the U.S. Department of Energy under Contract No. DE-AC02-CH03000 and by the U.S. Department of Energy, Office of Basic Energy Sciences, under Contract No. W-31-109-ENG-38. |
Optical transition radiation (OTR) detectors are being developed at Fermi National Acceleratory Laboratory (FNAL) as part of the collider Run II upgrade program and as part of the NuMI primary beamline. These detectors are designed to measure 150 GeV antiprotons as well as 120 GeV proton beams over a large range of intensities. Design and development of an OTR detector capable of measuring beam in both directions down to beam intensities of ~5·109 particles for nominal beam sizes is presented. Applications of these OTR detectors as an on-line emittance monitor for both antiproton transfers and reverse-injected protons, as a Tevatron injection profile monitor, and as a high-intensity beam profile monitor for NuMI are discussed. In addition, different types of OTR foils are being evaluated for operation over the intensity range of ~5·109 to over 1·1013 particles per pulse and these are described. |
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| RPAT064 | Beam-Based Calibration of the Electron Energy in the Fermilab Electron Cooler | electron, dipole, vacuum, kicker | 3638 | ||
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Electron cooling of 8.9 GeV antiprotons in the Fermilab’s Recycler ring requires precise matching of electron and antiproton velocities. While the final match can be done by optimization of the cooling process, for the very first cooling one should rely on the knowledge of absolute values of electron and antiproton energies. The upper limit for the energy uncertainty of both beams is determined by the Recycler’s momentum aperture and is equal to 0.3%. The paper discusses a method of the electron energy calibration that is based on the measurement of the electron’s Larmor wavelength in the field of the cooling section solenoid. The method was tested in an 18 m long cooling section prototype with 3.5 MeV electrons. An accuracy of 0.3% was demonstrated.
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| RPAT069 | Electron Beam Size Measurements in a Cooling Solenoid | electron, optics, radiation, focusing | 3801 | ||
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Funding: Operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
The Fermilab Electron Cooling Project requires a straight trajectory and constant beam size to provide effective cooling of the antiprotons in the Recycler. A measurement system was developed using movable appertures and steering bumps to measure the beam size in a 20 m long, nearly continuous, solenoid. This paper discusses the required beam parameters, the implimentation of the measurement system and results for our application. |
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| RPPT068 | Pion-Muon Concentrating System for Detectors of Highly Enriched Uranium | target, simulation, focusing, shielding | 3757 | ||
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One of many possible applications of low-energy antiprotons collected in a Penning trap can be a portable muon source. Released antiprotons annihilate on impact with normal matter producing on average about 3 charged pions per antiproton, which in turn decay into muons. Existence of such negative-muon sources of sufficient intensity would bring into play, for example, detectors of highly enriched uranium based on muonic X-rays. We explore options of collecting and focusing pions and resulting muons to enhance the muon flux toward the detector. Simulations with MARS and MAFIA are used to choose the target material and parameters of the magnetic system consisting of a few solenoids.
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| ROPA006 | Terascale Beam-Beam Simulations for Tevatron, RHIC and LHC | emittance, simulation, proton, injection | 535 | ||
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Funding: This work was supported by a SciDAC project in accelerator physics which is supported by the US DOE/SC Office of High Energy Physics and the Office of Advanced Scientific Computing Research. |
In this paper, we report on recent advances in terascale simulations of the beam-beam effects in Tevatron, RHIC and LHC. Computational methods for self-consistent calculation of the beam-beam forces are reviewed. Applications to the studies of the multiple bunch beam-beam interactions in the Tevatron and the RHIC will be presented. The study of emittance growth due to the beam-beam interactions in the LHC will also be presented. |
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| ROPC006 | Commissioning of Fermilab's Electron Cooling System for 8-GeV Antiprotons | electron, vacuum, beam-losses, simulation | 540 | ||
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A 4.3-MeV electron cooling system has been installed at Fermilab in the Recycler antiproton storage ring and is being currently commissioned. The cooling system is designed to assist accumulation of 8.9-GeV/c antiprotons for the Tevatron collider operations. This paper will report on the progress of the electron beam commissioning effort as well as on detailed plans of demonstrating the cooling of antiprotons.
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| FOAC004 | The Numi Neutrino Beam At Fermilab | target, proton, booster, hadron | |||
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The Neutrinos at the Main Injector (NuMI) is a conventional neutrino beam facility which will use the intense 120 GeV proton beam from the Fermilab Main Injector accelerator. The facility is envisaged to service a variety experiments, in particular the already-constructed MINOS long baseline oscillation experiment, and the proposed NOvA experiment to observe muon neutrino to electron neutrino oscillations. Summarized will be the design of the primary and secondary beam focusing systems, instrumentation to validate the neutrino beam intensity, direction, and energy spectrum, and considerations for coping with the 0.4 MWatt MI beam. The beam line will be commissioned December, 2004, through February, 2005, whereupon operations may begin. Data from the commissioning and experience from first operations will be presented. Further, the suitability of the facility for accepting beam from a proposed 2MW proton driver is discussed.
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| FPAE001 | Design Work for the High-Energy Storage Ring for Antiprotons of the Future GSI Project | electron, storage-ring, target, injection | 776 | ||
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The High-Energy Storage Ring (HESR) of the future international Facility for Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an antiproton cooler and storage ring in the momentum range from 1.5 to 15 GeV/c. The design work for the HESR is organized by a consortium with scientists from FZ Jülich, GSI Darmstadt and TSL Uppsala. An important feature of the new facility is the combination of phase space cooled beams with internal targets, resulting in demanding beam parameter in two operation modes: high luminosity mode with beam intensities up to few times 1011, and high resolution mode with a momentum spread down to 10-5, respectively. To reach these beam parameters very powerful phase space cooling is needed, utilizing high-energy electron cooling and high-bandwidth stochastic cooling. In this paper an overview of the design work is given, focusing on recent developments and planned R&D work.
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| FPAE008 | Iso-Adiabatic Merging of pbar Stacks in the Recycler | emittance, simulation, collider, hadron | 1093 | ||
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Funding: Work supported by the Universities Research Association, Inc., under contract DE-AC02-76CH03000 with the U.S. Department of Energy. |
Here, I have proposed an efficient scheme to merge two stacks of pbars in the Recycler* with emittance dilution <15%. First I discuss a method to match energy spreads of the two stacks and subsequently merging them. The scheme is illustrated with multiparticle dynamics simulations and beam measurements in the Recycler. *G. Jackson, Fermilab-TM-1991, November, 1996. |
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| FPAE012 | Experimental Test of a New Antiproton Acceleration Scheme in the Fermilab Main Injector | emittance, acceleration, injection, collider | 1303 | ||
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Funding: Operated by Universities Research Association, Inc. for the U.S. Department of Energy under contract DE-AC02-76CH03000. |
In an effort to provide higher intensity and lower emittance antiproton beam to the Tevatron collider for high luminosity operation, a new Main Injector (MI) antiproton acceleration scheme has been developed [1-4].* In this scheme, beam is accelerated from 8 to 27 GeV using the 2.5 MHz rf system and from 27 to 150 GeV using the 53 MHz rf system. This paper reports the experimental results of beam study. Simulation results are reported in a different PAC'05 paper [5]. Experiments are conducted with proton beam from the Booster. Acceleration efficiency, emittance growth and beam harmonic transfer between 2.5 MHz (h=28) and 53 MHz (h=588) buckets have been studied. Beam study shows that one can achieve an overall acceleration efficiency of about 100%, longitudinal emittance growth less than 20% and negligible transverse emittance growth. *G. P. Jackson, The Fermilab Recycler Ring Technical Design Report, FERMILAB-TM-1991, November 1996. |
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| FPAE017 | Observation of Longitudinal Diffusion and Cooling Due to Intrabeam Scattering at the Fermilab Recycler Ring | emittance, scattering, proton, luminosity | 1560 | ||
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The Fermilab Recycler Ring is a high vacuum fixed energy antiproton storage ring with both stochastic and electron cooling systems. In this note the technique for diffusion rate measurement, beam parameters and the analysis of data are presented, as well as the effect of intrabeam scattering on the operational considerations for the storage and cooling of the antiproton beam in the Recycler.
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| FPAE023 | Direct Antiproton Deceleration in the Fermilab Proton Driver | proton, simulation, synchrotron, H-minus | 1817 | ||
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The Fermilab Proton Driver is an 8 GeV kinetic energy H- linear accelerator proposed as a new source of high brightness protons for the Main Injector. The Recycler ring is an 8 GeV antiproton storage ring that resides in the same tunnel as the Main Injector. This paper describes a scenario wherein the current Main Injector proton injection kickers and Lambertson magnet are moved vertically into the Recycler ring to enable antiproton extraction toward the Proton Driver. By employing a pair of intermediate vertical bends at the appropriate vertical betatron phase advance, the vertical dispersion into the Proton Driver can be eliminated and direct antiproton deceleration made possible. Because the H- and antiproton beams have the same charge but opposite direction, matching of the Recycler lattice to the Proton Driver is required to accommodate the reversed effect of the focusing and defocusing quadrupoles.
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| FPAT005 | A Betatron Tune Fitting Package for the Tevatron 21.4 MHz Schottky | betatron, synchrotron, collider, pick-up | 937 | ||
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Accurate control of the Betatron tunes and chromaticities is required to optimize the dynamical aperture of any large synchrotron. The Fermilab Tevatron is equipped with two independent Schottky monitors, one operating at 21.4 MHz and the other 1.7 GHz. While the latter one allows us to characterize individual bunches separated by 396 ns, the former one has a larger Q and can give precise tune measurements. A new front-end and related data acquisition for this 21.4 MHz resonator has been installed and commissioned during the FY04 Collider RunII. Output signal are digitized at 100 KHz. Frequency spectra are transfered to dedicated server nodes and fitted in real time. Such frequency spectra are quite complex, due to inherent noise, horizontal/vertical coupling and synchrotron motion. Sophisticated fitting strategies are required. Optimization of this fitting package on relatively powerful commodity computer allows us to report tune and chromaticity measurements at almost 1 Hz. The architecture of the data acquisition system and this fitting package are described and results taken during the FY04 and FY05 runs are presented.
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| FPAT007 | The Fermilab Lattice Information Repository | lattice, optics, coupling, collider | 1066 | ||
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Funding: Fermilab is operated by Universities Research Association Inc. under Contract No. DE-AC02-76CH03000 with the United States Department of Energy. |
Fermilab is a large accelerator complex with six rings and sixteen transfer beamlines operating in various modes and configurations, subject to modifications, improvements and occasional major redesign. Over the years, it became increasingly obvious that a centralized lattice repository with the ability to track revisions would be of great value. To that end, we evaluated potentially suitable revision systems, either freely available or commercial, and decided that expecting infrequent users to become fully conversant with complex revision system software was neither realistic nor practical. In this paper, we discuss technical aspects of the recently introduced FNAL Accelerator Division's Lattice Repository, whose fully web-based interface hides the complexity of Subversion, a comprehensive open source revision system. In particular we emphasize how the architecture of Subversion was a key ingredient in the technical success of the repository's implementation. |
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| FPAT012 | Tevatron Beam Lifetimes at Injection Using the Shot Data Analysis System | proton, injection, beam-beam-effects, scattering | 1279 | ||
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The purpose of the Shot Data Acquisition and Analysis (SDA) system is to provide summary data on the Fermilab RunII accelerator complex and provide related software for detailed analyses. In this paper, we discuss such a specific analysis on Tevatron beam lifetimes at injection. These results are based on SDA data, tools and methodology. Beam lifetime is one of our most important diagnostics. An analysis of it can give information on intra beam scattering, aperture limitations, instabilities and most importantly beam-beam effects. Such an analysis gives us a better understanding of our machine, and will lead to an improved performance in the future.
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| FOPA003 | Challenges and Progress in the FAIR Accelerator Project | dipole, ion, synchrotron, proton | 294 | ||
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An international "Facility for Antiproton and Ion Research (FAIR)" was proposed to be built at GSI, providing unique conditions for experiments involving heavy ion and antiprotons beams. The new accelerator complex consists of the fast ramped s.c. heavy ion synchrotrons, SIS100/300 and a storage ring system for experiments with radioactive ions and antiprotons. The two stage concept for SIS100/300 provides optimum conditions for the generation of beams with high intensities per cycle and in average, over a wide energy range and with various time structures. Bunch compression enables a matching to the production targets and storage rings. The storage ring complex was optimized for fast cooling and accumulation of the generated secondary beams. Unique conditions for internal target experiments with radioactive beams will be provided in NESR and for antiproton beams in the high energy storage ring HESR. The new accelerators require R&D work in various fields of technologies and beam physics, as e.g. operation with low charge state, high intensity, heavy ion beams in dynamic vacuum conditions, development of fast ramped s.c. magnets, powerful, low frequency rf systems, stochastic cooling systems and medium energy electron coolers.
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