BIW2012 - List of Authors (Gassner, D.M.)

Paper

Title

Page

Conceptual Design of a High Precision Dual Directional Beam Position Monitoring System for Beam Crosstalk Cancellation and Improved Output Pulse Shapes

83

P. Thieberger, W.C. Dawson, W. Fischer, D.M. Gassner, R.L. Hulsart, K. Mernick, R.J. Michnoff, M.G. Minty
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Relativistic Heavy Ions Collider (RHIC) would benefit from improved beam position measurements near the interaction points that see both beams, especially as the tolerances become tighter when reducing the beam sizes to obtain increased luminosity. Two limitations of the present beam position monitors (BPMs) would be mitigated if the proposed approach is successful. The small but unavoidable cross-talk between signals from bunches traveling in opposite directions when using conventional BPMs will be reduced by adopting directional BPMs. Further improvements will be achieved by cancelling residual cross-talk using pairs of such BPMs. Appropriately delayed addition and integration of the signals will also provide pulses with relatively flat maxima that will be easier to digitize by relaxing the presently very stringent timing requirements.

Poster MOPG024 [0.959 MB]

MOPG025

Design of a Proton-Electron Beam Overlap Monitor for the New RHIC Electron Lens based on Detecting Energetic Backscattered Electrons

86

P. Thieberger, E.N. Beebe, W. Fischer, D.M. Gassner, X. Gu, K. Hamdi, J. Hock, T.A. Miller, M.G. Minty, C. Montag, A.I. Pikin
BNL, Upton, Long Island, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the ~0.3 mm RMS wide electron beams with the proton bunch trajectories over the ~2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e^- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.

Poster MOPG025 [0.793 MB]

MOPG026

A Wire Scanner System for Characterizing the BNL Energy Recovery Linac Beam Position Monitor System

89

R.J. Michnoff, C. Biscardi, P. Cerniglia, C. Degen, D.M. Gassner, L.T. Hoff, R.L. Hulsart
BNL, Upton, Long Island, New York, USA

A stepper motor controlled wire scanner assembly has recently been modified to support testing of the Brookhaven National Laboratory (BNL) Collider-Accelerator departments Energy Recovery Linac (ERL) beam position monitor (BPM) system. The ERL BPM consists of 4 9.33mm diameter buttons mounted at 90 degree spacing in a cube with 1.875 inside diameter. The buttons were designed by BNL and fabricated by Times Microwave Systems. Libera single pass BPM electronic modules, manufactured by Instrumentation Technologies, will be used to measure the X and Y transverse beam positions at 14 locations around the ERL. The wire scanner assembly provides the ability to measure the BPM button response to a pulsed wire, and evaluate and calibrate the Libera position measurement electronics. A description of the wire scanner system and test result data will be presented.
Work supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.

TUPG039

RHIC Electron-Lens Beam Profile Monitoring

213

T.A. Miller, J.N. Aronson, D.M. Gassner, A.I. Pikin
BNL, Upton, Long Island, New York, USA

In preparation for installation of an Electron Lens (E-Lens) into RHIC, planned for the summer of 2012, a test bench is being set up to allow the electron gun and collector assemblies, destined for the final E-Lens installation, to be tested together with a downsized mid-drift section. The goal of this effort is to test the electron gun and the collector designs, as well as the beam profiling instrumentation. A small unbiased Faraday cup, equipped with a grounded pin-hole mask, will intercept the beam; while an automated Control and data acquisition system will raster scan the electron beam across the detector. The collected integrated charge measurement is digitized and stored in an image type data file. This remote controlled plunging detector can be alternatively located in the same position as a plunging YAG:Ce crystal. A viewing port at the downstream extremity of the collector allows a GigE camera, fitted with a custom zoom lens, to image the crystal and digitize the profile of a beam pulse. Custom beam imaging software has been written to import both beam image files (pin-hole and YAG) and fully characterize the image of the beam profile.

Poster TUPG039 [30.885 MB]

WEAP01

Coherent Electron Cooling Proof of Principle Instrumentation Design

231

D.M. Gassner, V. Litvinenko, R.J. Michnoff, T.A. Miller, M.G. Minty, I. Pinayev
BNL, Upton, Long Island, New York, USA

Funding: US DOE
The goal of the Coherent Electron Cooling Proof-of-Principle experiment being designed at RHIC is to demonstrate longitudinal (energy spread) cooling before the expected CD-2 for eRHIC. The scope of the experiment is to cool longitudinally a single bunch of 40GeV/u Au ions in RHIC. This paper will describe the instrumentation systems proposed to meet the diagnostics challenges. These include measurements of beam intensity, emittance, energy spread, bunch length, position, orbit stability, and transverse and temporal alignment of electron and ion beams.

Paper	Title	Page
MOPG024	Conceptual Design of a High Precision Dual Directional Beam Position Monitoring System for Beam Crosstalk Cancellation and Improved Output Pulse Shapes	83
	P. Thieberger, W.C. Dawson, W. Fischer, D.M. Gassner, R.L. Hulsart, K. Mernick, R.J. Michnoff, M.G. Minty BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The Relativistic Heavy Ions Collider (RHIC) would benefit from improved beam position measurements near the interaction points that see both beams, especially as the tolerances become tighter when reducing the beam sizes to obtain increased luminosity. Two limitations of the present beam position monitors (BPMs) would be mitigated if the proposed approach is successful. The small but unavoidable cross-talk between signals from bunches traveling in opposite directions when using conventional BPMs will be reduced by adopting directional BPMs. Further improvements will be achieved by cancelling residual cross-talk using pairs of such BPMs. Appropriately delayed addition and integration of the signals will also provide pulses with relatively flat maxima that will be easier to digitize by relaxing the presently very stringent timing requirements.
	Poster MOPG024 [0.959 MB]

MOPG025	Design of a Proton-Electron Beam Overlap Monitor for the New RHIC Electron Lens based on Detecting Energetic Backscattered Electrons	86
	P. Thieberger, E.N. Beebe, W. Fischer, D.M. Gassner, X. Gu, K. Hamdi, J. Hock, T.A. Miller, M.G. Minty, C. Montag, A.I. Pikin BNL, Upton, Long Island, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the ~0.3 mm RMS wide electron beams with the proton bunch trajectories over the ~2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e^- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.
	Poster MOPG025 [0.793 MB]

MOPG026	A Wire Scanner System for Characterizing the BNL Energy Recovery Linac Beam Position Monitor System	89
	R.J. Michnoff, C. Biscardi, P. Cerniglia, C. Degen, D.M. Gassner, L.T. Hoff, R.L. Hulsart BNL, Upton, Long Island, New York, USA
	A stepper motor controlled wire scanner assembly has recently been modified to support testing of the Brookhaven National Laboratory (BNL) Collider-Accelerator departments Energy Recovery Linac (ERL) beam position monitor (BPM) system. The ERL BPM consists of 4 9.33mm diameter buttons mounted at 90 degree spacing in a cube with 1.875 inside diameter. The buttons were designed by BNL and fabricated by Times Microwave Systems. Libera single pass BPM electronic modules, manufactured by Instrumentation Technologies, will be used to measure the X and Y transverse beam positions at 14 locations around the ERL. The wire scanner assembly provides the ability to measure the BPM button response to a pulsed wire, and evaluate and calibrate the Libera position measurement electronics. A description of the wire scanner system and test result data will be presented. Work supported by Brookhaven Science Associates, LLC under contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.

TUPG039	RHIC Electron-Lens Beam Profile Monitoring	213
	T.A. Miller, J.N. Aronson, D.M. Gassner, A.I. Pikin BNL, Upton, Long Island, New York, USA
	In preparation for installation of an Electron Lens (E-Lens) into RHIC, planned for the summer of 2012, a test bench is being set up to allow the electron gun and collector assemblies, destined for the final E-Lens installation, to be tested together with a downsized mid-drift section. The goal of this effort is to test the electron gun and the collector designs, as well as the beam profiling instrumentation. A small unbiased Faraday cup, equipped with a grounded pin-hole mask, will intercept the beam; while an automated Control and data acquisition system will raster scan the electron beam across the detector. The collected integrated charge measurement is digitized and stored in an image type data file. This remote controlled plunging detector can be alternatively located in the same position as a plunging YAG:Ce crystal. A viewing port at the downstream extremity of the collector allows a GigE camera, fitted with a custom zoom lens, to image the crystal and digitize the profile of a beam pulse. Custom beam imaging software has been written to import both beam image files (pin-hole and YAG) and fully characterize the image of the beam profile.
	Poster TUPG039 [30.885 MB]

WEAP01	Coherent Electron Cooling Proof of Principle Instrumentation Design	231
	D.M. Gassner, V. Litvinenko, R.J. Michnoff, T.A. Miller, M.G. Minty, I. Pinayev BNL, Upton, Long Island, New York, USA
	Funding: US DOE The goal of the Coherent Electron Cooling Proof-of-Principle experiment being designed at RHIC is to demonstrate longitudinal (energy spread) cooling before the expected CD-2 for eRHIC. The scope of the experiment is to cool longitudinally a single bunch of 40GeV/u Au ions in RHIC. This paper will describe the instrumentation systems proposed to meet the diagnostics challenges. These include measurements of beam intensity, emittance, energy spread, bunch length, position, orbit stability, and transverse and temporal alignment of electron and ion beams.