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Reliability of the Fermilab Antiproton Source

Description: This paper reports on the reliability of the Fermilab Antiproton source since it began operation in 1985. Reliability of the complex as a whole as well as subsystem performance is summarized. Also discussed is the trending done to determine causes of significant machine downtime and actions taken to reduce the incidence of failure. Finally, results of a study to detect previously unidentified reliability limitations are presented.
Date: January 1, 1993
Creator: E.Harms, Jr.
Partner: UNT Libraries Government Documents Department

Measurements of Beam Momentum at the Stacking Energy of the Accumulator

Description: The momentum and orbit length of beam on the central and extraction orbits of the Antiproton Source Accumulator are calculated from measurements of revolution frequency and transverse beam position. This report gives the results of measurements made at the stacking energy before and after the 1998-99 Accumulator lattice upgrade. Before the lattice upgrade, the Accumulator central orbit length and momentum are measured to be: L{sub c} = 474.0433 {+-} 0.0025 m, p{sub c} = 8819.5 {+-} 4.1 MeV/c. After the lattice upgrade the central orbit length and momentum are measured to be: L{sub c} = 474.0532 {+-} 0.0016 m, p{sub c} = 8803.4 {+-} 2.7 MeV/c. The extraction orbit length and momentum prior to the lattice upgrade are measured to be: L{sub e} = 474.1916 {+-} 0.0054 m, p{sub e} = 8900.8 {+-} 9.2 MeV/c. After the lattice upgrade the extraction orbit length and momentum are measured to be: L{sub e} = 474.1599 {+-} 0.0036 m, p{sub e} = 8886.3 {+-} 6.1 MeV/c.
Date: November 29, 2000
Creator: Werkema, Steve
Partner: UNT Libraries Government Documents Department

A Pulsed Septum Magnet for the Fermilab Antiproton Source S. Holmes &

Description: A 2 meter curved pulsed septum magnet for use in the Fermilab Antiproton Source is described. The magnet produces a peak field of 6 kGauss at a current of 20,000 Amperes within a 0.4 msec long pulse. The field uniformity obtained is {Delta}B/B<0.2% out to 3.8 cm from the copper septum. Power enters the magnet from the center resulting in very simple ends and the magnet incorporates a 0.5 cm steel guard which reduces the field to <1.4 Gauss in the zero-field region. The total septum thickness is 1.3 cm. The vacuum enclosure doubles as the stacking fixture for the magnet laminations allowing easy assembly of a magnet with a 50 m radius of curvature.
Date: May 1, 1985
Creator: Satti, J.
Partner: UNT Libraries Government Documents Department

Improvements to Antiproton Accumulator to Recycler Transfers at the Fermilab Tevatron Collider

Description: Since 2005, the Recycler has become the sole storage ring for antiprotons used in the Tevatron Collider. The operational role of the Antiproton Source has shifted to exclusively producing antiprotons for periodic transfers to the Recycler. The process of transferring the antiprotons from the Accumulator to the Recycler has been greatly improved, leading to a dramatic reduction in the transfer time. The reduction in time has been accomplished with both an improvement in transfer efficiency and an increase in average stacking rate. This paper will describe the improvements that have streamlined the transfer process and other changes that contributed to a significant increase in the number of antiprotons available to the Collider.
Date: April 1, 2009
Creator: Morgan, J.P.; Drendel, B.; Vander Muelen, D. & /Fermilab
Partner: UNT Libraries Government Documents Department

Current and Future High Power Operation of Fermilab Main Injector

Description: Fermilab's Main Injector on acceleration cycles to 120 GeV has been running a mixed mode operation delivering beam to both the antiproton source for pbar production and to the NuMI[1] target for neutrino production since 2005. On January 2008 the slip stacking process used to increase the beam to the pbar target was expanded to include the beam to the NuMI target increasing the MI beam power at 120 GeV to 400KW. The current high power MI operation will be described along with the plans to increase the power to 700KW for NOvA and to 2.1 MW for project X.
Date: April 1, 2009
Creator: Kourbanis, I.; Adamson, P.; Brown, B.; Capista, D.; Chou, W.; Morris, D. et al.
Partner: UNT Libraries Government Documents Department

Curve Generation for the RF Systems of the Antiproton Source Console Program Specification and Implementation

Description: The RF curves program is a PDP-11 console application to calculate the time dependence of amplitude, frequency, and phase for the RF systems of the Antiproton Source. The results of the calculation are formatted and scaled for the curve generator hardware. The user interface of the program is highly flexible with respect to the choice of parameters used to specify the desired curve. It consists of file management, plotting, editing, and hardware loading phases which are implemented as separate pages on the console display. This document provides the functional specification of the program and a discussion of the status of its implementation.
Date: November 1, 1984
Creator: MacLachlan, J.A.
Partner: UNT Libraries Government Documents Department

AntiMatter Physics at Low Energy (AMPLE)

Description: The First Workshop on Antimatter Physics at Low Energy was held at FNAL last spring, April 10-12, 1986, with the stated purpose of gauging the interest in the physics that would be made possible by adding a variable energy pbar storage and cooling ring to the existing Accumulator at FNAL. The Workshop Proceedings are now published and include a concise collection of papers addressing the physics with pbars below 10 GeV/c that could be made available from the present antiproton source at FNAL. It is worth emphasizing that this is a possible without major impact on the primary mission of the laboratory. Such a facility would include provisions for extracted cooled pbar beams as well as future internal targer and colliding beam experiments. Specific experimental proposals would be facilitated by the existence of a reference design for such a facility. A central effort to produce such a reference design would be the logical next step. they are requesting the opportunity to present to this committee an overview of the physics arguments for such a facility; what we would require from the committee is 'strong encouragement' to proceed with such a reference design leading to a formal proposal. The aid of the FNAL staff in drawing up this reference design would be essential. One or more formal proposals for specific physics experiments would be forthcoming.
Date: January 1, 1986
Creator: Bonner, B.E.; U., /Rice; Pinsky, L.S. & U., /Houston
Partner: UNT Libraries Government Documents Department

New Target Results from the FNAL Antiproton Source

Description: Nickel and compressed rhenium powder targets have been installed in the FNAL antiproton source target station. Ni was chosen for its high melting point energy and resistance to stress wave fractures. As well, compressed powdered rhenium segments were constrained by a thin-wall Ti jacket to insure resistance to stress fractures. The {bar p} yield of these new targets is compared with that of copper - the previous standard production target. The target depletion characteristics of nickel and rhenium for a beam intensity of 1.6 x 10{sup 12} protons per pulse are also presented.
Date: January 1, 1992
Creator: O'Day, S.; Bieniosek, F.; Anderson, K. & /Fermilab
Partner: UNT Libraries Government Documents Department

Radiation Studies in the Antiproton Source

Description: Experiment E760 has a lead glass (Pb-G) calorimeter situated in the antiproton source tunnel in the accumulator ring at location A50. This location is exposed to radiation from several sources during antiproton stacking operations. A series of radiation studies has been performed over the last two years to determine the sources of this radiation and as a result, some shielding has been installed in the antiproton source in order to protect the lead glass from radiation damage.
Date: June 10, 1991
Creator: Church, Mike
Partner: UNT Libraries Government Documents Department

Utility Monitoring for the Antiproton Source

Description: The purpose of the utility portion of the FIRUS system is to alert humans in the main control room, at Phillips farm, and in building 10 control room when either environmental conditions are unhealthy for antiproton source devices, or electrical or mechanical equipment is malfunctioning. When first envisioned, the FIRUS system consisted of the following equipment: (1) 2 FIRUS mini-computers (wall mounted, 1 fire, 1 utility); (2) emergency power supply (also wall mounted); (3) coax hardline communication cable; (4) Junction boxes; (5) contact points and analog transducers; (6) three-pair 18 gage shielded cable; and (7) silent printer. Each mini can monitor 16 contact points or 15 analog points or a combination of contact and analog points. Each contact point can be more than one physical point if the points are wired in series. An alarm then indicates anyone of a group of points has opened. The following devices/quantities are proposed to be monitored by the utility portion of the FIRUS system: (1) sump pumps; (2) LCW (Low Conductivity Water); (3) auxiliary generator; (4) service building temperatures; (5) stub room/tunnel temperature; and (6) stub room/tunnel humidity. After the number of quantities to be monitored (see table I) was determined, it was found that two or three minis would be required, or a FIRUS crate could be used. A FIRUS crate is an 'old beam transfer crate' with 25 slots which hold cards to either monitor 16 contact points or 15 analog points. The space requirement for the crate system is about half a relay rack. The emergency power supply could remain wall mounted, or it could be rack mounted with the firus crate. Conversations with Al Franck and Rich Mahler concerning availability, expandability, cabling, and cost indicate that the FIRUS crate is the preperable option for the antiproton source.
Date: June 11, 1984
Creator: McConnell, D.
Partner: UNT Libraries Government Documents Department

Recent Measurement of Debuncher Longitudinal Beam Size During Stacking

Description: During the recent co11ider studies period there were a few time periods when 120 GeV beam was delivered with a slow repetition rate. This gave us a rare chance to study the effectiveness of additional cooling in the antiproton source. The measurements shown below were taken on 1/15/92. Although we have several FFT analyzers connected to the debuncher schottkey monitor we cannot readout the measured spectrum except with a TV camera. The following measurements, therefore, were taken with a spectrum analyzer. It is necessary to use a resolution bandwidth of 100 HZ to see the effectiveness of the momentum cooling system, and therefore the sweep time was 3 seconds. It took about 1 hour to complete the series of measurements. The main ring performance was up to it's normal standards during this time period, but it's performance can vary greatly from on minute to the next. The debuncher longitudinal schottkey spectra are shown in Figures 1-5 with different trigger times for the spectrum analyzer. These are shown using a scale linear in power, which should also be linear in particle density. There are two effects of momentum cooling that are apparent. (1) The momentum distribution after bunch rotation has very long non-gaussian tails, momentum cooling rapidly pushes these tails into the central peak. (2) The width of the central peak is gradually reduced, as is shown in Table I. The FWHM shown in TABLE I is at h=127, and the 95% dp/p is the full width in percent dp/p that contains 95% of the beam.
Date: February 18, 1992
Creator: Halling, Mike
Partner: UNT Libraries Government Documents Department

Design of Microwave Band Pass Filters for the Debuncher Stochastic Cooling System

Description: The FIR filters designed for the debuncher stochastic cooling system needed improvement. Its bandwidth was too wide, its magnitude was not flat, its phase ripple was too great, and it was difficult to control the characteristics of the filter. A simple microwave technique was employed to have a short time delay, simple robust layout, and small board size. A significant savings was seen over the FIR technique and these filters were installed in the Antiproton Source Debuncher while the FIR filters were removed from the debuncher stochastic cooling entirely.
Date: January 1, 2001
Creator: Deibele, C.
Partner: UNT Libraries Government Documents Department

Design of the Core 2-4 GHz Betatron Equalizer

Description: The core betatron equalizer in the Accumulator in the Antiproton Source at Fermilab needed to be upgraded. The performance could be rated as only circa 650 MHz when the system was a 2 GHz system. The old equalizer did not correct for the strong phase mismatch for the relatively strong gain of the system slightly below 2 GHz. The design corrects this phase mismatch and is relatively well matched both in and out of band.
Date: January 1, 2000
Creator: Deibele, C.
Partner: UNT Libraries Government Documents Department

Application of the Recent ARF1 Calibration Measurements to the Pbar RF Curve Loading Console Application (P2)

Description: The P2 console application (Antiproton Source RF Files) calculates frequency and voltage curves from a sequence of command statements input by the user. P2 initially calculates these curves in terms of the actual frequencies and voltages required on the RF cavity as a function of time. These curves are then converted to the appropriate low-level drive voltages that will cause the RF system high-level electronics to generate the required frequency and voltage ramps. The low-level drive ramps are then downloaded into CAMAC ramp cards. In order to convert the required cavity voltage and frequency into the correct drive voltages P2 uses a set of constants that determined from calibration measurements of the various Antiproton Source RF systems. These constants are editable from the P2 constants window. The P2 constants at the time of this writing are shown in Figure 1. The validity of these constants determines the extent to which P2 able to translate the user's commands into the actual voltages and frequencies that appear on the RF cavity. A comparison of the 4/18/2001 calibration of ARF1 with that presently assumed by P2 shows a large discrepancy in both the frequency constants and the voltage constants. This report documents the determination of the P2 ARF1 constants from the calibration measurements that were made on April 18, 2001. In addition, this report will compare the measured response of ARF1 to that derived from the present P2 constants. This comparison will be used to explain some resent observations of ARF1 behavior.
Date: April 21, 2001
Creator: Werkema, Steve
Partner: UNT Libraries Government Documents Department

Precision Measurement of the Accumulator Beam Energy

Description: The Antiproton Source Accumulator has been used by Fermilab experiments E760 and E835 to search for and measure the various states of charmonium below the open charm threshold. Accurate determination of the resonance parameters (mass, width, and branching ratios) of these states requires a precise measurement of the antiproton beam energy. The purpose of this report is to give a detailed description of the method that is used to accomplish a precision measurement of the antiproton beam energy.
Date: February 28, 2000
Creator: Werkema, Steven J.
Partner: UNT Libraries Government Documents Department

Production and Collections of Antiprotons

Description: The historical best antiproton yield obtained at the antiproton source is equal to 1.8 {center_dot} 10{sup -5}. That corresponds to the acceptance of about 17 mm {center_dot} mrad while the largest measured debuncher acceptance is about 25 mm {center_dot} mrad. It is expected that better debuncher tuning will increase the debuncher acceptance to about 35 mm {center_dot} mrad. Thus, improvements of optics and steering in the AP2 line and debuncher should allow an increase of antiproton yield by about 1.7 times to 3.1 {center_dot} 10{sup -5} for 35 mm {center_dot} mrad acceptance as shown in Figure 17. Although the maximum lithium lens gradient, which we can reliably achieve nowadays, is significantly below the optimum we should not expect significant increase of antiproton yield with lens upgrade. To reach the maximum antiproton yield with lens of the same length (15 cm) one would need to increase the lens gradient by 1.4 and 1.7 times correspondingly for 25 and 35 mm {center_dot} mrad acceptances. That corresponds to gradients of 105 and 127 kG/cm reaching of which is a challenging problem. And in spite of this significant increase of focusing strength that will bring only 13% and 16% antiproton yield increases corresponding to acceptances of 25 and 35 mm {center_dot} mrad. Minor improvement of about 3-4% can be achieved comparatively easy by lengthening of the lens by 20-30%.
Date: January 1, 2001
Creator: Lebedev, V.
Partner: UNT Libraries Government Documents Department

MI high power operation and future plans

Description: Fermilab's Main Injector on acceleration cycles to 120 GeV has been running a mixed mode operation delivering beam to both the antiproton source for pbar production and to the NuMI[1] target for neutrino production since 2005. On January 2008 the slip stacking process used to increase the beam to the pbar target was expanded to include the beam to the NuMI target increasing both the beam intensity and power. The current high power MI operation will be described along with the near future plans.
Date: September 1, 2008
Creator: Kourbanis, Ioanis
Partner: UNT Libraries Government Documents Department

Tevatron Run II performance and plans

Description: The Fermilab accelerator complex has been operating Run II for approximately one year. In this mode 36 proton bunches collide with 36 antiproton bunches at 2 interaction regions in the Tevatron at 980 GeV beam energy. The long range goal in Run II is to obtain a total integrated luminosity of 15 pb{sup -1}. The current status and performance of the accelerator complex is described, including the Tevatron, Main Injector, Antiproton Source, and Recycler Ring. Future upgrade plans and prospects for reaching the admittedly ambitious long range goal are presented.
Date: July 12, 2002
Creator: Church, Michael D
Partner: UNT Libraries Government Documents Department

Beam sweeping system

Description: This article describes a system for rapidly sweeping a high-energy particle beam in a circular path on a target. The sweeping system deflects the beam in a single-turn rotating-field magnet that combines deflection in both planes into a single unit. The magnet current is up to 10 kA in amplitude and the sweep time is 1.6 {micro}s. The magnet consists of 4 conductors twisted to provide a uniform line-integral deflecting magnetic field, arranged inside a pressed-powder magnetic core. The pulsed power supply provides the current to the high radiation area of the target vault through several meters of stripline and coaxial cable by means of a magnetic pulse compression circuit based on saturing Ni-Fe and Metglas tape cores. At the Fermilab Antiproton Source increase proton beam intensities incident on the antiproton production target threaten to deliver energy densities sufficient to locally melt the target in a single pulse. The purpose of the sweep magnet is to spread the hot spot on the target with a sweep radius of up to 0.5 mm, greatly reducing the peak energy deposition.
Date: August 8, 2000
Creator: al., F.M. Bieniosek et
Partner: UNT Libraries Government Documents Department

Antiproton noise source for the Tevatron

Description: A new system for exciting the beam in the Tevatron has been installed in the A1 service building and in the A17 medium straight section. The purpose of the system is to make betatron tune measurements.
Date: October 26, 1992
Creator: McConnell, D. & Fellenz, B.
Partner: UNT Libraries Government Documents Department

Operating Procedure Changes to Improve Antiproton Production at the Fermilab Tevatron Collider

Description: Since the start of Fermilab Collider Run II in 2001, the maximum weekly antiproton accumulation rate has increased from 400 x 10{sup 10} Pbars/week to approximately 3,700 x 10{sup 10} Pbars/week. There are many factors contributing to this increase, one of which involves changes to operational procedures that have streamlined and automated Antiproton Source production. Automation has been added to the beam line orbit control, stochastic cooling power level management, and RF settings. In addition, daily tuning efforts have been streamlined by implementing sequencer driven tuning software.
Date: April 1, 2009
Creator: Drendel, B.; Morgan, J.P.; Vander Meulen, D. & /Fermilab
Partner: UNT Libraries Government Documents Department

Design of 2-4 GHz Equalizers for the Antiproton Accumulator Stacktail System

Description: The antiproton source at Fermilab requires storage of antiprotons during the production of antiprotons. A fundamental part of the storage process involves stochastic cooling, which requires that the frequency spectrum from the pickups has notches at the revolution frequency and harmonics of the revolution frequency of the antiprotons in the storage ring. A system has been developed for broadband notches but suffers from dispersion. The dispersion inhibits the cooling process and therefore an equalizer is required. The process for designing the equalizers is described and results shown.
Date: January 1, 1999
Creator: Deibele, C. & /Wisconsin U., Madison
Partner: UNT Libraries Government Documents Department

Effect of Melting on Target Performance

Description: The brightness of the antiproton source increases as the proton beam spot size on the target is reduced. The RMS beam spot size may be reduced to below {sigma}{sub b} = 0.1 mm, before competing sources of emittance limit the achievable yield. At the same time, the density of energy deposition increases rapidly as the radius is reduced. Thus operation of the target at the highest yields subjects the target to very high peak energy deposition E{sub m}. Fits to the Monte-Carlo calculations of target yield and energy deposition from Ref. 1 are plotted in Figure 1. Experience has shown little or no sign of damage in copper targets up to about 500 J/g. If, as the energy density is increased, rupture of the copper target due to overpressure or shock-induced tensile stress does not occur, the ultimate brightness of the target will be limited by melting of the target material and consequent density depletion. This outcome was anticipated early in development of the antiproton source [Ref. 2]. The current memo addresses the melting problem with the goal of predicting the practical limitations of the target as the proton intensity is increased to 5 x 10{sup 12} protons per pulse. The predictions are made in a way that can be experimentally tested. They may also help determine the utility of a beam sweeping system.
Date: September 10, 1991
Creator: Bieniosek, F.M.
Partner: UNT Libraries Government Documents Department