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in creator/contributor: "SHEMYAKIN,A."

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Electron cooling rates characterization at Fermilab's Recycler

A 0.1 A, 4.3 MeV DC electron beam is routinely used to cool 8 GeV antiprotons in Fermilab's Recycler storage ring [1]. The primary function of the electron cooler is to increase the longitudinal phase-space density of the antiprotons for storing and preparing high-density bunches for injection into the Tevatron. The longitudinal cooling rate is found to significantly depend on the transverse emittance of the antiproton beam. The paper presents the measured rates and compares them with calculati… more

Date: June 1, 2007

Creator: Prost, Lionel R. & Shemyakin, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electron beam collector with a low back flow

Generation of a DC electron beam in the future Fermilab electron cooler [1] employs an electrostatic acceleration and a beam energy recovery, so that electrons are decelerated from the nominal energy of 4.3 MeV they have in the cooling section to few keV in the collector. Stable performance of this scheme requires a current loss {delta}I below 10 {micro}A at the beam current up to the nominal value of I = 0.5 A. One of sources of the loss is a back flow of secondary electrons from the beam coll… more

Date: March 17, 2004

Creator: Shemyakin, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Efficiency of the Fermilab Electron Cooler's collector

The newly installed Recycler Electron Cooling system (REC) at Fermilab [1] will work at an electron energy of 4.34 MeV and a DC beam current of 0.5 A in an energy recovery scheme. As a part of the Electron cooling project, the efficiency of the collector for the REC was optimized at a dedicated test bench to the level of relative current losses of 5 {center_dot} 10{sup -6}. The paper discusses the test bench measurements for several distributions of a transverse magnetic field in the collector … more

Date: May 1, 2005

Creator: Prost, L. R. & Shemyakin, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Full discharges in Fermilab's electron cooler

Fermilab's 4.3 MeV electron cooler is based on an electrostatic accelerator, which generates a DC electron beam in an energy recovery mode. Effective cooling of the antiprotons in the Recycler requires that the beam remains stable for hours. While short beam interruptions do not deteriorate the performance of the Recycler ring, the beam may provoke full discharges in the accelerator, which significantly affect the duty factor of the machine as well as the reliability of various components. Alth… more

Date: September 1, 2005

Creator: Prost, L. R. & Shemyakin, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Summary of Fermilab's Recycler Electron Cooler Operation and Studies

Fermilab's Recycler ring was used as a storage ring for accumulation and subsequent manipulations of 8 GeV antiprotons destined for the Tevatron collider. To satisfy these missions, a unique electron cooling system was designed, developed and successfully implemented. The most important features that distinguish the Recycler cooler from other existing electron coolers are its relativistic energy, 4.3 MV combined with 0.1-0.5 A DC beam current, a weak continuous longitudinal magnetic field in th… more

Date: May 15, 2012

Creator: Prost, L. R. & Shemyakin, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Effect of secondary ions on the electron beam optics in the Recycler Electron Cooler

Antiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1-0.5 A DC electron beam (as well as by a stochastic cooling system). The unique combination of the relativistic energy ({gamma} = 9.49), an Ampere-range DC beam, and a relatively weak focusing makes the cooling efficiency particularly sensitive to ion neutralization. A capability to clear ions was recently implemented by way of interrupting the electron beam for 1-30 {micro}s with a repetition rate of up to 40 Hz. The cooling p… more

Date: May 1, 2010

Creator: Shemyakin, A.; Prost, L.; Saewert, G. & /Fermilab

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Magnetic shielding of an electron beamline in a hadron accelerator enclosure

The Fermilab Electron Cooling Project requires the operation of a 4.34 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 busses 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 wel… more

Date: May 1, 2005

Creator: Kroc, T. K.; Schmidt, C. W. & Shemyakin, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Stability of electron energy in the Fermilab electron cooler

A powerful electron beam (4.3 MeV, 0.1 A DC) generated by an electrostatic accelerator has been used at Fermilab for three years to cool antiprotons in the Recycler ring. For electron cooling to be effective, the electron energy should not deviate from its optimum value by more than 500V. The main tool for studying the energy stability is the electron beam position in a high-dispersion area. The energy ripple (frequencies above 0.2 Hz) was found to be less than 150 eV rms; the main cause of the… more

Date: February 1, 2009

Creator: Shemyakin, A.; Carlson, K.; Prost, L. R. & Saewert, G.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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IBS in a CAM-Dominated Electron Beam

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.; Gusachenko, I.; Nagaitsev, S. & Shemyakin, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Low-energy run of Fermilab Electron cooler's beam generation system

N/A

Date: August 27, 2010

Creator: Prost, L.; Fedotov, A.; Shemyakin, A. & Kewisch, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Cooling in a compound bucket

Electron cooling in the Fermilab Recycler ring is found to create correlation between longitudinal and transverse tails of the antiproton distribution. By separating the core of the beam from the tail and cooling the tail using 'gated' stochastic cooling while applying electron cooling on the entire beam, one may be able to significantly increase the overall cooling rate. In this paper, we describe the procedure and first experimental results.

Date: September 1, 2007

Creator: Shemyakin, A.; Bhat, C.; Broemmelsiek, D.; Burov, A.; Hu, M. & /Fermilab

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Low-Energy Run of Fermilab Electron Cooler's Beam Generation System

In the context of the evaluation of possibly using the Fermilab Electron Cooler for the proposed low-energy RHIC run at BNL, operating the cooler at 1.6 MeV electron beam energy was tested in a short beam line configuration. The main conclusion of this feasibility study is that the cooler's beam generation system is suitable for BNL needs. The beam recirculation was stable for all tested parameters. In particular, a beam current of 0.38 A was achieved with the cathode magnetic field up to the m… more

Date: March 14, 2011

Creator: Prost, L. R.; Shemyakin, A.; Fedotov, A. & Kewisch, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Successful MeV-range electron beam recirculation

No Description Available.

Date: July 1, 1998

Creator: Crawford, A.C. FNAL; Nagaitsev, S. FNAL; Sharapa, A. INP & Shemyakin, A. INP

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Electron Cooling in the Recycler Cooler

A 0.1-0.5 A, 4.3 MeV DC electron beam provides cooling of 8 GeV antiprotons in Fermilab's Recycler storage ring. The most detailed information about the cooling properties of the electron beam comes from drag rate measurements. We find that the measured drag rate can significantly differ from the cooling force experienced by a single antiproton because the area of effective cooling is significantly smaller than the physical size of the electron beam and is comparable with the size of the antipr… more

Date: September 10, 2007

Creator: Shemyakin, A.; Prost, L. R.; Fedotov, A. & Sidorin, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Optimization of electron cooling in the Recycler

Antiprotons in Fermilab's Recycler ring are cooled by a 4.3 MeV, 0.1A DC electron beam (as well as by a stochastic cooling system). The paper describes electron cooling improvements recently implemented: adjustments of electron beam line quadrupoles to decrease the electron angles in the cooling section and better stabilization and control of the electron energy.

Date: April 1, 2009

Creator: Shemyakin, A.; Burov, A.; Carlson, K.; Prost, L. R.; Sutherland, M. & Warner, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Recycler Electron Cooling Project: Mechanical vibrations in the Pelletron and their effect on the beam

The Fermilab's Recycler ring will employ an electron cooler to cool stored 8.9 GeV antiprotons [1]. The cooler is based on an electrostatic accelerator, Pelletron [2], working in an energy-recovery regime. A full-scale prototype of the cooler has been assembled and commissioned in a separate building [3]. The main goal of the experiments with the prototype was to demonstrate stable operation with a 3.5 MeV, 0.5 A DC electron beam while preserving a high beam quality in the cooling section. The … more

Date: July 1, 2005

Creator: Kazakevich, Grigory M.; Burov, A.; Boffo, C.; Joireman, P.; Saewert, G.; Schmidt, C. W. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Transverse Instabilities in the Fermilab Recycler

Transverse instabilities of the antiproton beam have been observed in the Recycler ring soon after its commissioning. After installation of transverse dampers, the threshold for the instability limit increased significantly but the instability is still found to limit the brightness of the antiprotons extracted from the Recycler for Tevatron shots. In this paper, we describe observations of the instabilities during the extraction process as well as during dedicated studies. The measured instabil… more

Date: July 1, 2011

Creator: Prost, L. R.; Burov, A.; Shemyakin, A.; Bhat, C. M.; Crisp, J. & Eddy, N.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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The design and implementation of the machine protection system for the Fermilab electron cooling facility

The Fermilab Recycler ring employs an electron cooler to store and cool 8.9-GeV antiprotons. The cooler is based on a 4.3-MV, 0.1-A, DC electrostatic accelerator for which current losses have to remain low ({approx}10{sup -5}) in order to operate reliably. The Machine Protection System (MPS) has been designed to interrupt the beam in a matter of 1-2 {micro}s when losses higher than a safe limit are detected, either in the accelerator itself or in the beam lines. This paper highlights the variou… more

Date: May 1, 2009

Creator: Warner, A.; Carmichael, L.; Carlson, K.; Crisp, J.; Goodwin, R.; Prost, L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Electron beam size measurements in a cooling solenoid

The Fermilab Electron Cooling Project [1] 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 apertures and steering bumps to measure the beam size in a 20m long, nearly continuous, solenoid. This paper discusses the required beam parameters, the implementation of the measurement system and results for our application.

Date: May 1, 2005

Creator: Kroc, T. K.; Burov, A. V.; Bolshakov, T. B.; Shemyakin, A.; /Fermilab; Seletskiy, S. M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Electron beam size measurements in the Fermilab Electron Cooling System

The Fermilab Electron Cooling Project requires a straight trajectory and constant beam size to provide maximum cooling of the antiprotons in the Recycler. A measurement system was developed using movable apertures and steering bumps to measure the beam size in a 20m long, nearly continuous, solenoid. This paper will focus on results of these measurements of the beam size and the difficulties in making those measurements.

Date: September 1, 2005

Creator: Kroc, T.K.; Burov, A.V.; Bolshakov, T.B.; Shemyakin, A.; /Fermilab; Seletskiy, S.M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Transverse instability of the antiproton beam in the Recycler Ring

The brightness of the antiproton beam in Fermilab's 8 GeV Recycler ring is limited by a transverse instability. This instability has occurred during the extraction process to the Tevatron for large stacks of antiprotons even with dampers in operation. This paper describes observed features of the instability, introduces the threshold phase density to characterize the beam stability, and finds the results to be in agreement with a resistive wall instability model. Effective exclusion of the long… more

Date: March 1, 2011

Creator: Prost, L. R.; Bhat, C. M.; Burov, A.; Crisp, J.; Eddy, N.; Hu, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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PXIE Optics and Layout

The Project X Injector Experiment (PXIE) will serve as a prototype for the Project X front end. The aim is to validate the Project-X design and to decrease technical risks mainly related to the front end. The paper discusses the main requirements and constraints motivating the facility layout and optics. Final adjustments to the Project X front end design, if needed, will be based on operational experience gained with PXIE.

Date: May 1, 2012

Creator: Lebedev, V. A.; Nagaitsev, S.; Ostiguy, J. F.; Shemyakin, A. V.; Shteynas, B. G.; Solyak, N. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Progress with PXIE MEBT Chopper

A capability to provide a large variety of bunch patterns is crucial for the concept of the Project X serving MW-range beam to several experiments simultaneously. This capability will be realized by the Medium Energy Beam Transport's (MEBT) chopping system that will divert 80% of all bunches of the initially 5 mA, 2.1 MeV CW 162.5 MHz beam to an absorber according to a pre-programmed bunch-by-bunch selection. Being considered one of the most challenging components, the chopping system will be t… more

Date: May 1, 2012

Creator: Lebedev, V.; Chen, A.; Pasquinelli, R; Peterson, D.; Saewert, G.; Shemyakin, A. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Design Considerations for an MEBT Chopper Absorber of 2.1 MeV H- at the Project X Injector Experiment at Fermilab

The Project X Injector Experiment (PIXIE) will be a prototype of the Project X front end that will be used to validate the design concept and decrease technical risks. One of the most challenging components of PIXIE is the wide-band chopping system of the Medium Energy Beam Transport (MEBT) section, which will form an arbitrary bunch pattern from the initially CW 162.5 MHz 5mA beam. The present scenario assumes diverting 80% of the beam to an absorber to provide a beam with the average current … more

Date: May 14, 2012

Creator: Baffes, C.; Awida, M.; Chen, A.; Eidelman, Y.; Lebedev, V.; Prost, L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department