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Calibration of Accumulator and Debuncher Scrapers

Description: During the past week a careful calibration of the accumulator and debuncher scrapers was made. The procedure was to measure the actual scraper movement relative to some fixed external reference point with a caliper while observing the readback of the associated ACNET device on a VAX console. The results of this calibration are summarized.
Date: March 30, 1992
Creator: Ellerbrock, A.; Werkema, S.; Wisner, B. & /Fermilab
Partner: UNT Libraries Government Documents Department

Transverse Emittance Growth in the Fermilab Antiproton Accumulator with High-Current Antiproton Stacks

Description: Transverse emittance growth due to coherent instabilities in the Fermilab antiproton accumulator imposes a limit on the number of antiprotons which can be stacked and subsequently transferred to the collider. Consequences, the diagnosis and control of these phenomena has been required to further increase the luminosity of the collider. In this paper they present an overview of the techniques by which these instabilities have been studied and the methods by which they are controlled.
Date: January 1, 1992
Creator: Werkema, Steven J.; Peterson, David W.; Zhou, Ping & /Fermilab
Partner: UNT Libraries Government Documents Department

Investigations Into Accumulator 4-8 GHz Pickup Loop / Combiner Board Performance

Description: A set of pickup measurements performed in August of 1999 (see Pbar note 618) indicated problems with the pickup sensitivity for frequencies above {approx}4.8 GHz. This note describes the effort made to determine if the problems with system performance were due to the design of the 4-8 GHz circuit board.
Date: April 17, 2000
Creator: Vander Meuler, D.
Partner: UNT Libraries Government Documents Department

Procedures for Deceleration Studies

Description: The purpose of deceleration studies is to construct the deceleration ramp files that are used to decelerate antiproton beam for experiment E835. A deceleration ramp file is a set of ramp tables that are downloaded to PAUX (a part of the Pbar front end) prior to a deceleration. There is a ramp table for each device that is changed during a deceleration. These tables determine how PAUX changes each device setting during a deceleration. Appendix 1 gives a table of all ramped devices. Presently a deceleration to the lowest energy allowed by our ramps requires the use of three ramp files: the first decelerates the beam from 8801 MeV/c to 6367 MeV/c, the second from 6367 MeV/c to 4858 MeV/c, and the third from 4858 MeV/c to 3900 MeV/c. At the time of this writing the third ramp file has yet to be completed. An important new feature of the present deceleration ramp files is that the value of {gamma}{sub t} is decreased as the beam is decelerated so that the Accumulator is always above transition.
Date: November 5, 1999
Creator: Werkema, Steve
Partner: UNT Libraries Government Documents Department

Optimization of the 8 GeV AP3-P1 Lattice for Antiproton Transfers

Description: During 8 GeV antiproton transfers between the Accumulator to the Main Injector, the antiprotons must travel through four separate beam lines, AP3, AP1, P2, and P1. This note describes the optimization of a single lattice that describes these beam lines for 8 GeV antiproton transfers from the Accumulator to the Main Injector and 8 GeV proton transfers from the Main Injector to the Accumulator.
Date: January 22, 2001
Creator: McGinnis, Dave
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

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

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

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

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

Performance and upgrades of the Fermilab Accumulator stacktail stochastic cooling

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: November 1, 2005
Creator: Derwent, P.F.; Cullerton, Ed; McGinnis, David; Pasquinelli, Ralph; Sun, Ding; Tinsley, David 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

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

Antiproton Extraction in the Fermilab Antiproton Accumulator

Description: The RF and other manipulations required to extract antiprotons from the Accumulator core for Collider operation are described. ESME simulations of the motion in longitudinal phase space are shown. Measurements of the emittances of the extracted antiprotons are presented. The effect of the unstacking process on the core longitudinal and transverse emittances is examined and recent performance is also presented.
Date: January 1, 1993
Creator: Church, Mike; O'Day, Stephan & /Fermilab
Partner: UNT Libraries Government Documents Department

A Review of the 1991 E760 Run

Description: The 1991 E760 run was highly successful. This note is an attempt to record some important information regarding Accumulator operation during the run, so that it will be easily accessible for the next E760 run. The topics are not in any particularly relevant order, but are taken mostly from a seminar given by M. Church on 2/13/92. Much ramp data resides in the 'E760 Ramps Notebook' and much other data resides in E760 logbooks V, VI, VII, and VIII. Table 1 summarizes the data collected during the run. Fig. 1 shows the luminosity collected week by week and the average stacking rate per stack. Fig. 2 shows the luminosity integrated through the run. A total of 31 pb{sup -1} was collected. Fig 3. shows a typical deceleration (above transition) with a typical efficiency of 95%. Early in the run the efficiency was very close to 100%. I suspect there was an aperture restriction - possibly a momentum aperture limitation as we wandered too close to the edge of the momentum aperture. The deceleration efficiency really should be 100%. Fig. 4 shows a typical data-taking cycle. The break point 2/3rds through the data-taking is a deceleration to the {eta}{sub c}. Fig. 4a and 4b show horizontal and vertical aperture as a function of momentum for the 1990 ramps and 1991 ramps as measured in Jan. 1991. During the run, the actual apertures were known to be smaller. The problem of radiation during stacking was solved during this run by the addition of more shielding. Fig. 4c shows the final layout of shielding blocks. A 40 mA stack gave about 3 mrads of radiation in the Pb-G as measured by standard chipmunks. The total amount of radiation received during the run was about 100 rads - bringing the total to about 200 ...
Date: February 20, 1992
Creator: Church, M.
Partner: UNT Libraries Government Documents Department

Measurement of Escaping Ions in the Fermilab Antiproton Accumulator

Description: Positively charged ions trapped in the negatively charged beam of the Fermilab antiproton accumulator pose a limit to beam stability and density. To better understand the dynamics and the consequences of the beam-ion interaction, they have built and installed a low energy ion detector and energy analyzer in the Fermilab accumulator. This analyzer is capable of energy analysis of the escaping ions using a probe with energy retarding grids and may also be scanned in the pitch angle of the escaping ions. Measurements have been made in both longitudinal and transverse planes under a variety of machine operating conditions. The experimental measurement results are presented together with attempts to model the ion dynamics and explain observations.
Date: January 1, 1992
Creator: Zhou, P.; Colestock, P.L.; Junck, K.; Crawford, C.A. & /Fermilab
Partner: UNT Libraries Government Documents Department

Measurement of Trapped Ion Pockets and Control of Ion Instabilities in the Fermilab Antiproton Accumulator

Description: Resonant interaction of positively charged, trapped residual gas ions with a negatively charged, intense antiproton beam has been identified as the primary cause of transverse instability in the Fermilab antiproton accumulator. An upgraded ion clearing system was recently installed. This upgrade yielded a significant improvement in machine performance as well as an enhanced capability for studying trapped ion related phenomena. The operational impact and preliminary results from some initial measurements made with this system are presented herein.
Date: January 1, 1993
Creator: Werkema, Steven J.; Fullett, Kenneth D.; Zhou, Ping & /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

Transition Crossing Improvements

Description: During the accelerator studies period of 12/90-1/91 efforts were made to improve the efficiency of crossing transition in the Accumulator. E760 wishes to measure the product of the branching ratios for {bar p}p {yields} {eta}{sub c} {yields} {gamma}{gamma} and the mass and width of the {eta}{sub c}. Since resonance production of the {eta}{sub c} requires a beam momentum of 3.67 Gev/c which is below the Accumulator design transition momentum, and since the above process is rare, it is required to cross transition efficiently (> 90%) with 30 mA of beam. In the past, transition crossing efficiency has been intensity-dependent, with never more than 10 mA getting through transition. At 8 mA or less, transition crossing efficiency was typically 100%. The beam loss is due to a large longitudinal beam blow-up which has been observed many times during transition crossing.
Date: April 25, 1991
Creator: Church, M.
Partner: UNT Libraries Government Documents Department

Effects of Transverse Coupling on Transverse Beam Size, Simulation and Measurements

Description: The equations of motion for particles in an accelerator lattice show that a larger physical aperture is required to hold a beam of constant invariant emittance if there is a transverse coupling of the tunes. The results of a tracking simulation of particle motion in the Fermilab accumulator ring are discussed, and results are shown from beam tests carried out in the accumulator to demonstrate this effect.
Date: January 1, 1992
Creator: Halling, Alfred Mike
Partner: UNT Libraries Government Documents Department

Emittance Growth Due to Steering Errors for the 8 GeV AP3-P1 Lattice

Description: During 8 GeV antiproton transfers between the Accumulator to the Main Injector, the antiprotons must travel through four separate beam lines, AP3, AP1, P2, and P1. The AP1, P1, and P2 transfer lines are also used for 120 GeV antiproton production so that many of the magnet strings must accommodate a large range of excitation current. This note will quantify the relationship between emittance dilution for 8 GeV antiprotons injected into the Main Injector and variations in the excitation currents of the bending magnets.
Date: January 23, 2001
Creator: McGinnis, Dave
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

Accumulator Betatron Core Cooling Scenarios

Description: Scenarios for the Accumulator 4-8 GHz betatron core cooling systems are described. Included are signal and noise calculations, optimum gain values and settings, and total power levels necessary. Comparisons are made to the Run I system performance with both the coaxial line and laser link from A10 to A30.
Date: November 19, 1999
Creator: Derwent, Paul
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

RF Curves for Extraction from the Accumulator

Description: Since the start of Run IIa, the RF curves for the extraction process from the Accumulator have been based on an algorithm described in Pbar Note 636. There are a number of problems with this procedure that result in a dilution of the longitudinal phase space of the extracted beam. The procedure consists of a number of steps in which the frequency curve during each process is a linear time ramp. For a constant bend field, the synchronous phase angle is given as: {Lambda} = sin({phi}{sub s}) = -h/{eta} (1/f{sub rf}){sup 2}df{sub rf}/dt/qV/pc where h is the harmonic number of the RF. Equation (1) shows that if the frequency curve consists of a number of linear time ramps with different slopes, there will be discontinuities in the synchronous phase. These discontinuities in the synchronous phase will lead to dipole oscillations of the beam in the RF bucket. The discontinuities observed for the present RF curves are about 10 degrees. In the procedure outlined in Pbar Note 636, the RF bucket is formed on the high energy edge of the rectangular momentum distribution. As the RF bucket is pulled away from the core, it is also programmed to increase in area. If the distribution is not perfectly rectangular, or if the bucket is not formed at the edge of the distribution, the growing bucket will gather up more particles at the edges of the bucket resulting in a substantial increase of longitudinal emittance. Finally, it is fairly difficult to prepare a rectangular momentum distribution and keep it rectangular for extended periods of time. Once the rectangular distribution is prepared, the core momentum cooling must be turned off. If there is a delay in the extraction process, the sharp edges of the rectangular distribution will soon diffuse. With the momentum cooling disabled, ...
Date: March 10, 2002
Creator: McGinnis, Dav
Partner: UNT Libraries Government Documents Department