17 results on '"Jay, Benesch"'
Search Results
2. Measurement of the beam-normal single-spin asymmetry for elastic electron scattering from C12 and Al27
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R. W. Radloff, S. A. Page, John M. Finn, L. Lee, V. Tvaskis, L. Z. Ndukum, K. E. Mesick, S. Kowalski, Jongmin Lee, W. S. Duvall, A. Mkrtchyan, A. R. Lee, C. A. Davis, P. Solvignon, William A. Tobias, J. Leacock, Jay Benesch, J. A. Dunne, F. Guo, H. Mkrtchyan, M. M. Dalton, R. D. Carlini, B. Sawatzky, S. MacEwan, T. Seva, W. D. Ramsay, E. Korkmaz, D. G. Meekins, Kent Paschke, P. M. King, V. M. Gray, V. Tadevosyan, D. C. Jones, J. C. Cornejo, Jean-Francois Rajotte, J. Pan, M. H. Shabestari, P. Wang, J. A. Magee, R. S. Beminiwattha, Michael Gericke, R. Michaels, Fatiha Benmokhtar, Wouter Deconinck, B. Waidyawansa, D. S. Armstrong, Jonathan W. Martin, R. Subedi, S. Covrig Dusa, M. Kargiantoulakis, J. Leckey, Dipanwita Dutta, S. P. Wells, W. R. Falk, S. A. Wood, P. Zang, Darko Androić, D. T. Spayde, Vladimir Nelyubin, D. J. Mack, S. Zhamkochyan, M. E. Christy, A. Asaturyan, R. Silwal, J. F. Dowd, S. K. Phillips, T. A. Forest, J. Birchall, M. Elaasar, Geoffrey Smith, A. Subedi, R. Mahurin, M. J. McHugh, Riad Suleiman, Michael Pitt, Amrendra Narayan, D. Gaskell, V. Owen, C. Gal, W. T. H. van Oers, Nuruzzaman, J. R. Hoskins, Juliette Mammei, K. Bartlett, J. Roche, and Neven Simicevic
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Elastic scattering ,Physics ,Range (particle radiation) ,010308 nuclear & particles physics ,Scattering ,media_common.quotation_subject ,01 natural sciences ,Asymmetry ,Nuclear physics ,Momentum ,Transverse plane ,0103 physical sciences ,High Energy Physics::Experiment ,Nuclear Experiment ,010306 general physics ,Beam (structure) ,Spin-½ ,media_common - Abstract
We report measurements of the parity-conserving beam-normal single-spin elastic scattering asymmetries $B_n$ on $^{12}$C and $^{27}$Al, obtained with an electron beam polarized transverse to its momentum direction. These measurements add an additional kinematic point to a series of previous measurements of $B_n$ on $^{12}$C and provide a first measurement on $^{27}$Al. The experiment utilized the Qweak apparatus at Jefferson Lab with a beam energy of 1.158 GeV. The average lab scattering angle for both targets was 7.7 degrees, and the average $Q^2$ for both targets was 0.02437 GeV$^2$ (Q=0.1561 GeV). The asymmetries are $B_n$ = -10.68 $\pm$ 0.90 stat) $\pm$ 0.57 (syst) ppm for $^{12}$C and $B_n$ = -12.16 $\pm$ 0.58 (stat) $\pm$ 0.62 (syst) ppm for $^{27}$Al. The results are consistent with theoretical predictions, and are compared to existing data. When scaled by Z/A, the Q-dependence of all the far-forward angle (theta < 10 degrees) data from $^{1}$H to $^{27}$Al can be described by the same slope out to $Q \approx 0.35$ GeV. Larger-angle data from other experiments in the same Q range are consistent with a slope about twice as steep.
- Published
- 2021
3. Accurate Determination of the Neutron Skin Thickness of Pb208 through Parity-Violation in Electron Scattering
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S. Rahman, H. Albataineh, B. Yale, K. S. Kumar, S. Seeds, A. Deshpande, C. Ayerbe Gayoso, A. Yoon, Q. Campagna, G. M. Urciuoli, G. Leverick, R. Mammei, Bogdan Wojtsekhowski, D. S. Armstrong, Paul Souder, Siyu Jian, C. Palatchi, S. Johnston, C. Jantzi, H. Bhatt, P. E. Reimer, B. Karki, Dipangkar Dutta, T. Ye, D. King, D. McNulty, M. Knauss, L. G. Tang, J. C. Cornejo, T. Gautam, S. Katugampola, P. M. King, R. W. Radloff, H. Liu, J. O. Hansen, J. Pan, D. C. Jones, Michael Pitt, S. Riordan, E. W. Wertz, S. Park, R. Michaels, Y. Tian, C. Metts, M. N. H. Rashad, P. Datta, S. Premathilake, S. Malace, W. Zhang, S. Covrig Dusa, Y. Roblin, I. Halilovic, K. A. Aniol, T. Averett, S. Barcus, C. Feldman, N. Liyange, B. Pandey, A. Zec, E. Fuchey, Charles Horowitz, Jay Benesch, Michaela Thiel, Kent Paschke, A. Narayan, C. Ghosh, D. Adhikari, Brendan Reed, B. P. Quinn, Jiawen Zhang, F. Hauenstein, Cynthia Keppel, M. Petrusky, Darko Androić, G. D. Cates, D. G. Meekins, R. Richards, V. Bellini, N. Lashley-Colthirst, A. Rathnayake, M. M. Mondal, X. Zheng, Michael Gericke, M. McCaughan, Andrew Puckett, Juliette Mammei, A. Camsonne, A. Shahinyan, B. Blaikie, C. Clarke, D. Gaskell, Y. Chen, Jim Napolitano, V. Owen, C. Gal, D. Nikolaev, D. Bhetuwal, R. S. Beminiwattha, W. Henry, T. Kutz, and D. Bhatta Pathak
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Elastic scattering ,Physics ,Equation of state (cosmology) ,media_common.quotation_subject ,Form factor (quantum field theory) ,General Physics and Astronomy ,01 natural sciences ,Asymmetry ,0103 physical sciences ,Saturation (graph theory) ,Neutron ,Atomic physics ,010306 general physics ,Electron scattering ,Energy (signal processing) ,media_common - Abstract
We report a precision measurement of the parity-violating asymmetry A_{PV} in the elastic scattering of longitudinally polarized electrons from ^{208}Pb. We measure A_{PV}=550±16(stat)±8(syst) parts per billion, leading to an extraction of the neutral weak form factor F_{W}(Q^{2}=0.00616 GeV^{2})=0.368±0.013. Combined with our previous measurement, the extracted neutron skin thickness is R_{n}-R_{p}=0.283±0.071 fm. The result also yields the first significant direct measurement of the interior weak density of ^{208}Pb: ρ_{W}^{0}=-0.0796±0.0036(exp)±0.0013(theo) fm^{-3} leading to the interior baryon density ρ_{b}^{0}=0.1480±0.0036(exp)±0.0013(theo) fm^{-3}. The measurement accurately constrains the density dependence of the symmetry energy of nuclear matter near saturation density, with implications for the size and composition of neutron stars.
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- 2021
4. The GlueX beamline and detector
- Author
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T. Whitlatch, N. Wickramaarachchi, N. Cao, Ilya Larin, Michael Dugger, N. K. Walford, V. V. Tarasov, Gerard Visser, W. Phelps, J. Frye, B. Liu, J. Stewart, V. Razmyslovich, S. Schadmand, B. E. Cannon, C.P. Romero, O. Cortes, F. Nerling, S. Adhikari, M. M. Dalton, G. Voulgaris, C. S. Akondi, W. J. Briscoe, J. R. Stevens, W. D. Crahen, G.H. Biallas, H. Marukyan, R.S. Pedroni, C. Gleason, W. McGinley, P. Eugenio, E. Wolin, V. Crede, C. Carlin, L. A. Teigrob, F. Mokaya, T. C. Black, A. Toro, D. G. Meekins, I. A. Semenova, Elton Smith, A. Thiel, Kamal K. Seth, G. J. Lolos, A. M. Schertz, Todd Satogata, G. Kalicy, T. Daniels, N. S. Jarvis, A. Hamdi, I. I. Strakovsky, N. Qin, Mark Richard James Williams, I. Vega, A. Tsaris, Y. Yang, K. Goetzen, T. Erbora, J. Leckey, W. U. Boeglin, R. T. Jones, S. Fegan, D. S. Carman, K. Suresh, V. V. Berdnikov, Barry Ritchie, G. Vasileiadis, T. Carstens, E. Barriga, H. Al Ghoul, K. Moriya, J. Hardin, A. Gerasimov, M. E. McCracken, A. Deur, C. D. Keith, M. J. Staib, Hovanes Egiyan, A. Ali, Vladimir Popov, Jay Benesch, A. Hurley, C. Dickover, Viktor Matveev, Dmitri Romanov, A. Dolgolenko, B. Pratt, Justin I. McIntyre, C. A. Meyer, R. Mendez, A. R. Dzierba, C. Hutton, N. Sandoval, G. M. Huber, L. Guo, Z. Papandreou, Zhiyong Zhang, D. I. Sober, E. Pooser, J. Foote, J. Zarling, M. M. Ito, O. Chernyshov, Blake Leverington, S. Cole, P. Brindza, H. Hakobyan, A. Barnes, Sean A Dobbs, E. G. Anassontzis, T. D. Beattie, D. Werthmüller, X. Shen, Amiran Tomaradze, M. Patsyuk, J. Ritman, M. McCaughan, C. Fanelli, Yujie Qiang, R. A. Miskimen, A. Somov, R. Kliemt, F. Barbosa, A. Austregesilo, R. Dzhygadlo, C. Salgado, B. C.L. Sumner, L. Robison, Joerg Reinhold, Ting Xiao, A. Schick, V. Kakoyan, William Brooks, D. J. Mack, W. I. Levine, N. Gevorgyan, S. Katsaganis, E. Chudakov, Pavlos Ioannou, Lubomir Pentchev, A. Goncalves, A. Yu. Semenov, A. I. Ostrovidov, A. M. Foda, R. Dotel, M. Kamel, R. A. Schumacher, D. G. Ireland, W. B. Li, M. R. Shepherd, Ashot Gasparian, A. Teymurazyan, Krisztian Peters, J. Barlow, B. Zihlmann, Xiang Zhou, J. Pierce, S. Taylor, N. Sparks, L. Gan, S. Somov, L. Ng, A. Ernst, D. Kolybaba, K. Livingston, V. S. Goryachev, Cornelius Schwarz, P. Mattione, Y. Van Haarlem, P. Pauli, I. Tolstukhin, J. Schwiening, M. J. Amaryan, D. Lawrence, J. Brock, H. Ni, C. Stanislav, V. Lyubovitskij, S. Furletov, T. Britton, R. Barsotti, C. Paudel, Christine Kourkoumelis, Sergey Kuleshov, R. E. Mitchell, D. I. Lersch, C. L. Henschel, Q. Zhou, O. Soto, Friedrich Klein, and S.T. Krueger
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Nuclear and High Energy Physics ,GlueX, детектор ,Physics - Instrumentation and Detectors ,Photon ,Physics::Instrumentation and Detectors ,фотонный пучок ,FOS: Physical sciences ,Scintillator ,01 natural sciences ,Optics ,Hodoscope ,0103 physical sciences ,ddc:530 ,Nuclear Experiment (nucl-ex) ,010306 general physics ,Nuclear Experiment ,Instrumentation ,Physics ,GlueX ,Spectrometer ,Calorimeter (particle physics) ,010308 nuclear & particles physics ,business.industry ,Detector ,Instrumentation and Detectors (physics.ins-det) ,Beamline ,High Energy Physics::Experiment ,business - Abstract
The GlueX experiment at Jefferson Lab has been designed to study photoproduction reactions with a 9-GeV linearly polarized photon beam. The energy and arrival time of beam photons are tagged using a scintillator hodoscope and a scintillating fiber array. The photon flux is determined using a pair spectrometer, while the linear polarization of the photon beam is determined using a polarimeter based on triplet photoproduction. Charged-particle tracks from interactions in the central target are analyzed in a solenoidal field using a central straw-tube drift chamber and six packages of planar chambers with cathode strips and drift wires. Electromagnetic showers are reconstructed in a cylindrical scintillating fiber calorimeter inside the magnet and a lead-glass array downstream. Charged particle identification is achieved by measuring energy loss in the wire chambers and using the flight time of particles between the target and detectors outside the magnet. The signals from all detectors are recorded with flash ADCs and/or pipeline TDCs into memories allowing trigger decisions with a latency of 3.3 $\mu$s. The detector operates routinely at trigger rates of 40 kHz and data rates of 600 megabytes per second. We describe the photon beam, the GlueX detector components, electronics, data-acquisition and monitoring systems, and the performance of the experiment during the first three years of operation., Comment: Accepted by Nuclear Instruments and Methods A, 78 pages, 54 figures
- Published
- 2021
5. Precision Measurement of the Beam-Normal Single-Spin Asymmetry in Forward-Angle Elastic Electron-Proton Scattering
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Wouter Deconinck, Riad Suleiman, M. H. Shabestari, L. Z. Ndukum, William A. Tobias, C. A. Davis, J. Leckey, J. A. Magee, S. Yang, Jongmin Lee, Amrendra Narayan, P. Solvignon, mrow, J. Roche, V. Tvaskis, M. M. Dalton, W. D. Ramsay, A. Mkrtchyan, S. MacEwan, D. Gaskell, M. Elaasar, Nuruzzaman, J. Beaufait, T. Seva, E. Korkmaz, V. M. Gray, A. R. Lee, B. Waidyawansa, D. T. Spayde, S. Covrig Dusa, Jean-Francois Rajotte, Roger Carlini, S. K. Phillips, mrow> weak, R. Subedi, M. K. Jones, Kent Paschke, K. Bartlett, S. A. Wood, P. Wang, Neven Simicevic, V. Owen, A. Asaturyan, W. R. Falk, J. Leacock, R. W. Radloff, R. Mahurin, P. Zang, Dipangkar Dutta, V. Tadevosyan, C. Gal, Fatiha Benmokhtar, J.C. Cornejo, K. E. Mesick, L. Lee, Vladimir Nelyubin, P. M. King, A. M. Micherdzinska, S. A. Page, F. Guo, H. Mkrtchyan, D. J. Mack, Darko Androić, R. S. Beminiwattha, mtext, A. Subedi, S. Zhamkochyan, W. T. H. van Oers, M. Kargiantoulakis, T. A. Forest, Michael Gericke, J. F. Dowd, Joseph Grames, S. Wells, J. M. Finn, K. Grimm, J. Pan, R. Silwal, J. A. Dunne, B. Sawatzky, D. C. Jones, R. Michaels, J. R. Hoskins, J. Birchall, Juliette Mammei, S. Kowalski, W. S. Duvall, J. W. Martin, J. Mei, N. Morgan, msub, R. T. Jones, Jay Benesch, Michael Pitt, D. G. Meekins, D. S. Armstrong, G. R. Smith, and M. J. McHugh
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Physics ,Scattering ,media_common.quotation_subject ,General Physics and Astronomy ,FOS: Physical sciences ,Observable ,Electron ,beam-normalization, single-spin asymmetry, scattering, transversaly polarized electrons, unpolarized nucleons ,01 natural sciences ,Asymmetry ,0103 physical sciences ,High Energy Physics::Experiment ,Atomic physics ,Nuclear Experiment (nucl-ex) ,010306 general physics ,Nucleon ,Nuclear Experiment ,Energy (signal processing) ,Beam (structure) ,Spin-½ ,media_common - Abstract
A beam-normal single-spin asymmetry generated in the scattering of transversely polarized electrons from unpolarized nucleons is an observable related to the imaginary part of the two-photon exchange process. We report a 2% precision measurement of the beam-normal single-spin asymmetry in elastic electron-proton scattering with a mean scattering angle of theta_lab = 7.9 degrees and a mean energy of 1.149 GeV. The asymmetry result is B_n = -5.194 +- 0.067 (stat) +- 0.082 (syst) ppm. This is the most precise measurement of this quantity available to date and therefore provides a stringent test of two-photon exchange models at far-forward scattering angles (theta_lab -> 0) where they should be most reliable., 6 pages, 3 figures; Slightly revised version, after referee's comments; accepted in PRL
- Published
- 2020
6. Compact −300 kV dc inverted insulator photogun with biased anode and alkali-antimonide photocathode
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Yan Wang, M. Tiefenback, Riad Suleiman, Carlos Hernandez-Garcia, M. A. Mamun, G. Palacios-Serrano, Helmut Baumgart, J. Jordan, Shukui Zhang, Philip Adderley, Joseph Grames, J. Hansknecht, Jay Benesch, R. Montoya Soto, B. Bullard, M. Poelker, Geoffrey Krafft, C. A. Valerio Lizarraga, Joseph Gubeli, A. Canales Ramos, R. Kazimi, S. Wijethunga, F. E. Hannon, Marcy Stutzman, and J. Yoskowitz
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Nuclear and High Energy Physics ,Materials science ,Physics and Astronomy (miscellaneous) ,business.industry ,High voltage ,Insulator (electricity) ,Surfaces and Interfaces ,Photocathode ,Anode ,Ion ,Antimonide ,Optoelectronics ,Quantum efficiency ,Thermal emittance ,business - Abstract
This contribution describes the latest milestones of a multiyear program to build and operate a compact $\ensuremath{-}300\text{ }\text{ }\mathrm{kV}$ dc high voltage photogun with inverted insulator geometry and alkali-antimonide photocathodes. Photocathode thermal emittance measurements and quantum efficiency charge lifetime measurements at average current up to 4.5 mA are presented, as well as an innovative implementation of ion generation and tracking simulations to explain the benefits of a biased anode to repel beam line ions from the anode-cathode gap, to dramatically improve the operating lifetime of the photogun and eliminate the occurrence of micro-arc discharges.
- Published
- 2019
7. A novel comparison of Møller and Compton electron-beam polarimeters
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Dipangkar Dutta, William A. Tobias, Amber McCreary, W.D. Ramsay, A. Mkrtchyan, B. S. Cavness, Douglas Storey, Kent Paschke, S. A. Page, C. Vidal, Amrendra Narayan, D. Gaskell, L. A. Dillon-Townes, D. C. Jones, P. Wang, Erik Urban, M. McDonald, J.C. Cornejo, J. R. Hoskins, R. S. Beminiwattha, Vladimir Nelyubin, A. Asaturyan, M. M. Dalton, Wouter Deconinck, S. Zhamkotchyan, E. Ihloff, P. Solvignon, G. Hays, R. T. Jones, P. M. King, S. Kowalski, J. W. Martin, V. Tvaskis, J. A. Magee, A. Micherdzinska, B. Waidyawansa, H. Mkrtchyan, L. Lee, Jay Benesch, Leonid Kurchaninov, G. D. Cates, Massachusetts Institute of Technology. Department of Physics, and Kowalski, Stanley B
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Nuclear and High Energy Physics ,Physics - Instrumentation and Detectors ,media_common.quotation_subject ,Polarimetry ,Electron ,Electron polarimetry ,01 natural sciences ,Asymmetry ,Møller polarimeter ,Optics ,Compton polarimeter ,0103 physical sciences ,High current ,010306 general physics ,Nuclear Experiment ,media_common ,Physics ,010308 nuclear & particles physics ,business.industry ,Astrophysics::Instrumentation and Methods for Astrophysics ,Compton scattering ,Polarimeter ,Polarization (waves) ,lcsh:QC1-999 ,Computational physics ,Cathode ray ,Physics::Accelerator Physics ,business ,lcsh:Physics ,Jefferson Lab - Abstract
We have performed a novel comparison between electron-beam polarimeters based on Møller and Compton scattering. A sequence of electron-beam polarization measurements were performed at low beam currents (< 5μA) during the Q[subscript weak] experiment in Hall-C at Jefferson Lab. These low current measurements were bracketed by the regular high current (180 μA) operation of the Compton polarimeter. All measurements were found to be consistent within experimental uncertainties of 1% or less, demonstrating that electron polarization does not depend significantly on the beam current. This result lends confidence to the common practice of applying Møller measurements made at low beam currents to physics experiments performed at higher beam currents. The agreement between two polarimetry techniques based on independent physical processes sets an important benchmark for future precision asymmetry measurements that require sub-1% precision in polarimetry. Keywords: Electron polarimetry, Compton polarimeter, Møller polarimeter, Jefferson Lab, United States. Department of Energy (Contract AC05-06OR23177), Natural Sciences and Engineering Research Council of Canada
- Published
- 2017
8. Precision Measurement of the Weak Charge of the Proton
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K. Bartlett, K. E. Mesick, W. R. Falk, P. M. King, R. S. Beminiwattha, A. Asaturyan, J. Leckey, P. Zang, J. Leacock, T. Averett, D. T. Spayde, M. M. Dalton, Ross D. Young, W. D. Ramsay, Vladimir Nelyubin, J. Balewski, J. F. Dowd, J. Roche, S. Yang, Darko Androić, A. Micherdzinska, M. Kargiantoulakis, John M. Finn, J. A. Magee, Kent Paschke, Jongmin Lee, R. W. L. Jones, P. Solvignon, S. Kowalski, L. Z. Ndukum, W. S. Duvall, S. Zhamkochyan, J. Birchall, V. Tvaskis, Riad Suleiman, A. R. Lee, B. Waidyawansa, J. Pan, D. C. Jones, Fatiha Benmokhtar, Wouter Deconinck, Jonathan W. Martin, S. Covrig Dusa, L. Lee, A. Mkrtchyan, Amrendra Narayan, R. Michaels, S. P. Wells, M. H. Shabestari, Geoffrey Smith, D. Gaskell, C. A. Davis, William A. Tobias, Jay Benesch, H. Mkrtchyan, Matthew Jones, Joseph Grames, S. A. Page, A. K. Opper, S. MacEwan, T. Seva, E. Korkmaz, Jean-Francois Rajotte, V. M. Gray, M. Poelker, C. Gal, D. S. Armstrong, J. A. Dunne, S. A. Wood, J. Mei, J. Beaufait, R. D. Carlini, Kathryn Grimm, F. Guo, S. K. Phillips, J. Diefenbach, P. Wang, D. J. Mack, N. Morgan, Michael Gericke, B. Sawatzky, T. A. Forest, R. Silwal, M. J. McHugh, M. Elaasar, R. Mahurin, J. C. Cornejo, Michael Pitt, R. Subedi, W. T. H. van Oers, Nuruzzaman, H. Nuhait, J. R. Hoskins, D. G. Meekins, Juliette Mammei, V. Tadevosyan, Dipangkar Dutta, Neven Simicevic, and A. Subedi
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Physics ,Particle physics ,Multidisciplinary ,Large Hadron Collider ,010308 nuclear & particles physics ,media_common.quotation_subject ,Electroweak interaction ,Dark matter ,FOS: Physical sciences ,Elementary particle ,Parity (physics) ,Weak interaction ,7. Clean energy ,01 natural sciences ,Asymmetry ,0103 physical sciences ,Higgs boson ,Nuclear Experiment (nucl-ex) ,010306 general physics ,weak charge of proton, parity violation, polarized electron beam ,Nuclear Experiment ,media_common - Abstract
The fields of particle and nuclear physics have undertaken extensive programs to search for evidence of physics beyond that explained by current theories. The observation of the Higgs boson at the Large Hadron Collider completed the set of particles predicted by the Standard Model (SM), currently the best description of fundamental particles and forces. However, the theory's limitations include a failure to predict fundamental parameters and the inability to account for dark matter/energy, gravity, and the matter-antimater asymmetry in the universe, among other phenomena. Given the lack of additional particles found so far through direct searches in the post-Higgs era, indirect searches utilizing precise measurements of well predicted SM observables allow highly targeted alternative tests for physics beyond the SM. Indirect searches have the potential to reach mass/energy scales beyond those directly accessible by today's high-energy accelerators. The value of the weak charge of the proton Q_W^p is an example of such an indirect search, as it sets the strength of the proton's interaction with particles via the well-predicted neutral electroweak force. Parity violation (invariance under spatial inversion (x,y,z) -> (-x,-y,-z)) is violated only in the weak interaction, thus providing a unique tool to isolate the weak interaction in order to measure the proton's weak charge. Here we report Q_W^p=0.0719+-0.0045, as extracted from our measured parity-violating (PV) polarized electron-proton scattering asymmetry, A_ep=-226.5+-9.3 ppb. Our value of Q_W^p is in excellent agreement with the SM, and sets multi-TeV-scale constraints on any semi-leptonic PV physics not described within the SM., Direct link to Nature Version "https://rdcu.be/954U"
- Published
- 2019
9. Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm
- Author
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Balša Terzić, Alicia S. Hofler, Cody J. Reeves, Sabbir A. Khan, Geoffrey A. Krafft, Jay Benesch, Arne Freyberger, and Desh Ranjan
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Nuclear and particle physics. Atomic energy. Radioactivity ,QC770-798 - Abstract
In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab’s Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.
- Published
- 2014
- Full Text
- View/download PDF
10. Magnetized electron beam for the JLEIC re-circulator cooler ring
- Author
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M. A. Mamun, Yan Wang, Carlos Hernandez-Garcia, Fay Hannon, Joseph Grames, M. Poelker, R. Kazimi, B. Bullard, Philip Adderley, J. Yoskovitz, Geoffrey Krafft, S. Wijiethunga, M.G. Tiefenback, Shukui Zhang, Riad Suleiman, J. Hansknecht, and Jay Benesch
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Physics ,Optics ,Ion beam ,business.industry ,Circulator ,Cathode ray ,Physics::Accelerator Physics ,High voltage ,Electron ,business ,Beam (structure) ,Ion ,Electron gun - Abstract
The ion beams of the proposed Jefferson Lab Electron Ion Collider (JLEIC) must be cooled to achieve the required collision luminosity. In general, cooling is accomplished when an electron beam co-propagates with an ion beam moving at the same average velocity, but with different temperature, where the energy of chaotic motion of the ion beam is transferred to the cold electron beam. The cooling rate can be improved by about two orders of magnitude if the process occurs inside a solenoidal magnetic field – so-called magnetized cooling - that forces the electrons to follow small helical trajectories thereby increasing the interaction time with ions and improving the cooling efficiency. However, one of the challenges associated with implementing this cooling technique relates to the fringe field of the cooling solenoid which imparts a large unwanted azimuthal kick onto the electron beam that prevents the electron beam from traveling in the desired tight, well-defined volume within the solenoid. As proposed by Derbenev, the ill-effect of this fringe field can be cancelled if the electron beam is born in a similar field and encountering a fringe field upon exiting the electron gun that produces an azimuthal kick in the opposite direction, such that the two kicks cancel. Besides requiring magnetized beam, the JLEIC re-circulator cooler design requires an electron beam with very high average current and high bunch charge: 140 mA and with nanoCoulomb bunch charge. This contribution describes the latest milestones of a multiyear program to build a magnetized electron beam source based on a 350 kV DC high voltage photogun with inverted insulator geometry.
- Published
- 2018
11. Production of Highly Polarized Positrons Using Polarized Electrons at MeV Energies
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Sadiq Setiniyaz, G. Bosson, D. Abbott, M. Ungaro, J. S. Real, A. Camsonne, C. Cuevas, Adeleke Hakeem Adeyemi, T. A. Forest, E. Forman, H. Dong, Riad Suleiman, P. Aguilera, R. Kazimi, Yiyang Zhang, Y. Kim, Y. Wang, M. Poelker, Joseph Grames, T. Michaelides, J. L. McCarter, D. McNulty, P. Harrell, S. Golge, M. Marton, Marcy Stutzman, B. Moffit, Chris Tennant, E. Fanchini, L. Richardson, J. R. Hoskins, K. Mahoney, D. Machie, Dennis Turner, E. Froidefond, M D Muhd Ali, Brian P. Josey, P. Gueye, M. Mchugh, M. Baylac, D. S. Dale, L. S. Cardman, Alessandro Variola, C.-Y. Tsai, P. L. Cole, R. Michaels, C. Munoz Camacho, Brian E. Cade, C. E. Hyde, A. P. Freyberger, D. Moser, H. Areti, Jean-François Muraz, R. Mammei, A. Opper, Philip Adderley, Jay Benesch, J. Dumas, M. McCaughan, O. Dadoun, J. Clark, K. E. Mesick, E. Voutier, S. Covert, J. Hansknecht, Laboratoire de Physique Subatomique et de Cosmologie (LPSC), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de l'Accélérateur Linéaire (LAL), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut de Physique Nucléaire d'Orsay (IPNO), and Peppo Collaboration
- Subjects
Accelerator Physics (physics.acc-ph) ,Positron beam ,Astrophysics::High Energy Astrophysical Phenomena ,[PHYS.PHYS.PHYS-ACC-PH]Physics [physics]/Physics [physics]/Accelerator Physics [physics.acc-ph] ,FOS: Physical sciences ,General Physics and Astronomy ,Electron ,7. Clean energy ,01 natural sciences ,High Energy Physics - Experiment ,law.invention ,Nuclear physics ,High Energy Physics - Experiment (hep-ex) ,Positron ,Electron beam accelerator ,law ,0103 physical sciences ,Nuclear Experiment (nucl-ex) ,010306 general physics ,Nuclear Experiment ,Physics ,010308 nuclear & particles physics ,Bremsstrahlung ,Particle accelerator ,Polarization (waves) ,3. Good health ,Cathode ray ,Physics::Accelerator Physics ,Physics - Accelerator Physics ,High Energy Physics::Experiment ,Atomic physics - Abstract
The Polarized Electrons for Polarized Positrons experiment at the injector of the Continuous Electron Beam Accelerator Facility has demonstrated for the first time the efficient transfer of polarization from electrons to positrons produced by the polarized bremsstrahlung radiation induced by a polarized electron beam in a high-$Z$ target. Positron polarization up to 82\% have been measured for an initial electron beam momentum of 8.19~MeV/$c$, limited only by the electron beam polarization. This technique extends polarized positron capabilities from GeV to MeV electron beams, and opens access to polarized positron beam physics to a wide community., Comment: 5 pages, 4 figures
- Published
- 2016
12. The tracking analysis in the Q-weak experiment
- Author
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T. Averett, M. M. Dalton, A.K. Opper, W. D. Ramsay, D. T. Spayde, K. Johnston, Kent Paschke, J. Mei, J.C. Cornejo, William A. Tobias, F. Guo, P. M. King, W. R. Falk, Vladimir Nelyubin, S. A. Wood, R. Mahurin, J. Leacock, Fatiha Benmokhtar, D. J. Mack, Jean-Francois Rajotte, S. A. Page, D. G. Meekins, J. Pan, Michael Gericke, S. Wells, S. Kowalski, J. Balewski, W. S. Duvall, J. Leckey, R. T. Jones, A. Mkrtchyan, M. H. Shabestari, J. W. Martin, Nuruzzaman, M. Elaasar, C. A. Davis, L. Z. Ndukum, B. Sawatzky, M. Kargiantoulakis, J. Grames, J. A. Magee, Roger Carlini, S. K. Phillips, P. Solvignon, G. D. Cates, S. Yang, Jongmin Lee, D. C. Jones, J. Diefenbach, N. Morgan, Wouter Deconinck, W. T. H. van Oers, Darko Androić, R. Michaels, V. M. Gray, A. R. Lee, B. Waidyawansa, S. MacEwan, T. Seva, E. Korkmaz, Jay Benesch, V. Tvaskis, J. Beaufait, R. Subedi, A. Asaturyan, R. Suleiman, S. Zhamkochyan, K. E. Myers, H. Mkrtchyan, D. S. Armstrong, G. R. Smith, J. A. Dunne, P. Wang, L. Lee, Dipangkar Dutta, K. Grimm, A. Subedi, S. Covrig, M. J. McHugh, Michael Pitt, Neven Simicevic, J. M. Finn, J. R. Hoskins, J. Roche, J. Birchall, T. A. Forest, Juliette Mammei, A. Micherdzinska, V. Tadevosyan, M. K. Jones, R. Silwal, Amrendra Narayan, M. Poelker, D. Gaskell, R. S. Beminiwattha, Ross D. Young, and J. F. Dowd
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Physics ,Nuclear and High Energy Physics ,Particle physics ,Spectrometer ,business.industry ,Scattering ,media_common.quotation_subject ,Momentum transfer ,Tracking system ,Parity (physics) ,Kinematics ,Electron ,Condensed Matter Physics ,01 natural sciences ,Asymmetry ,Atomic and Molecular Physics, and Optics ,010305 fluids & plasmas ,Nuclear physics ,q-weak experiment ,0103 physical sciences ,Physical and Theoretical Chemistry ,010306 general physics ,business ,Nuclear Experiment ,media_common - Abstract
The Q-weak experiment at Jefferson Laboratory measured the parity violating asymmetry (A P V ) in elastic electron-proton scattering at small momentum transfer squared (Q 2=0.025 (G e V/c)2), with the aim of extracting the proton’s weak charge ( ${Q^p_W}$ ) to an accuracy of 5 %. As one of the major uncertainty contribution sources to ${Q^p_W}$ , Q 2 needs to be determined to ∼1 % so as to reach the proposed experimental precision. For this purpose, two sets of high resolution tracking chambers were employed in the experiment, to measure tracks before and after the magnetic spectrometer. Data collected by the tracking system were then reconstructed with dedicated software into individual electron trajectories for experimental kinematics determination. The Q-weak kinematics and the analysis scheme for tracking data are briefly described here. The sources that contribute to the uncertainty of Q 2 are discussed, and the current analysis status is reported.
- Published
- 2016
13. Precision Electron-Beam Polarimetry at 1 GeV Using Diamond Microstrip Detectors
- Author
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P. M. King, G. D. Cates, Dipangkar Dutta, M. M. Dalton, W. D. Ramsay, M. McDonald, B. S. Cavness, A. Tobias, S. Kowalski, L. Lee, Wouter Deconinck, H. Mkrtchyan, B. Waidyawansa, J. C. Cornejo, Vladimir Nelyubin, S. A. Page, Kent Paschke, R. W. L. Jones, S. Zhamkotchyan, Jonathan W. Martin, Douglas Storey, P. Solvignon, G. Hays, Amber McCreary, Jay Benesch, P. Wang, L. A. Dillon-Townes, A. Asaturyan, E. Ihloff, V. Tvaskis, A. Mkrtchyan, Erik Urban, D. C. Jones, C. Vidal, A. Micherdzinska, Leonid Kurchaninov, Amrendra Narayan, D. Gaskell, Bates Linear Accelerator Center, Massachusetts Institute of Technology. Department of Physics, Massachusetts Institute of Technology. Laboratory for Nuclear Science, Ihloff, Ernest E., Kowalski, Stanley B., and Vidal, Christopher J.
- Subjects
Physics ,010308 nuclear & particles physics ,business.industry ,Scattering ,QC1-999 ,Compton scattering ,Polarimetry ,General Physics and Astronomy ,Diamond ,Electron ,engineering.material ,01 natural sciences ,Particle detector ,Optics ,Deflection (physics) ,0103 physical sciences ,Cathode ray ,engineering ,Physics::Accelerator Physics ,010306 general physics ,business - Abstract
We report on the highest precision yet achieved in the measurement of the polarization of a low-energy, O(1 GeV), continuous-wave (CW) electron beam, accomplished using a new polarimeter based on electron-photon scattering, in Hall C at Jefferson Lab. A number of technical innovations were necessary, including a novel method for precise control of the laser polarization in a cavity and a novel diamond microstrip detector that was able to capture most of the spectrum of scattered electrons. The data analysis technique exploited track finding, the high granularity of the detector, and its large acceptance. The polarization of the 180-μA, 1.16-GeV electron beam was measured with a statistical precision of, United States. Dept. of Energy (Contract AC05-06OR23177), National Science Foundation (U.S.), Natural Sciences and Engineering Research Council of Canada
- Published
- 2015
14. Simple modification of Compton polarimeter to redirect synchrotron radiation
- Author
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Kent Paschke, Jay Benesch, B. P. Quinn, and G. B. Franklin
- Subjects
Physics ,Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,business.industry ,Orders of magnitude (temperature) ,FOS: Physical sciences ,Synchrotron radiation ,Particle accelerator ,Polarimeter ,Surfaces and Interfaces ,20399 Classical Physics not elsewhere classified ,Linear particle accelerator ,law.invention ,Dipole ,Optics ,law ,Physics::Accelerator Physics ,lcsh:QC770-798 ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Chicane ,business ,Beam (structure) - Abstract
Synchrotron radiation produced as an electron beam passes through a bending magnet is a significant source of background in many experiments. Using modeling, we show that simple modifications of the magnet geometry can reduce this background by orders of magnitude in some circumstances. Specifically, we examine possible modifications of the four dipole magnets used in Jefferson Lab’s Hall A Compton polarimeter chicane. This Compton polarimeter has been a crucial part of experiments with polarized beams and the next generation of experiments will utilize increased beam energies, up to 11 GeV, requiring a corresponding increase in Compton dipole field to 1.5 T. In consequence, the synchrotron radiation (SR) from the dipole chicane will be greatly increased. Three possible modifications of the chicane dipoles are studied; each design moves about 2% of the integrated bending field to provide a gentle bend in critical regions along the beam trajectory which, in turn, greatly reduces the synchrotron radiation within the acceptance of the Compton polarimeter photon detector. Each of the modifications studied also softens the SR energy spectrum at the detector sufficiently to allow shielding with 5 mm of lead. Simulations show that these designs are each capable of reducing the background signal duemore » to SR by three orders of magnitude. The three designs considered vary in their need for vacuum vessel changes and in their effectiveness.« less
- Published
- 2015
15. The Qweak experimental apparatus
- Author
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J. R. Hoskins, R. S. Beminiwattha, J. Birchall, J. Diefenbach, Juliette Mammei, J. Balewski, Erik Urban, J. F. Dowd, K. Johnston, G. Clark, P.W. Rose, B. Sawatzky, P. Solvignon, M. Kargiantoulakis, M. Elaasar, J. Mei, S. Sobczynski, A. Micherdzinska, A. Kubera, M. K. Jones, R.B. Zielinski, Mitchell D. Anderson, T. Averett, R. Suleiman, V. M. Gray, E. Henderson, R.D. Carlini, S. A. Wood, Neven Simicevic, J. D. Bowman, A. Mkrtchyan, Amber McCreary, Darko Androić, V. Tvaskis, E. Bonnell, N. Morgan, R. Mahurin, Kent Paschke, R. Averill, J. Beaufait, J. Roche, S. Zhamkochyan, D. J. Mack, C. A. Davis, Fatiha Benmokhtar, S. A. Page, D.C. Dean, J. M. Finn, P. Medeiros, Jean-Francois Rajotte, R. Subedi, G. D. Cates, S. Wells, F. Guo, S. MacEwan, P. Wang, J. A. Dunne, Jongmin Lee, T. Seva, E. Korkmaz, S. K. Phillips, D. C. Jones, P. Brindza, Amrendra Narayan, M. Poelker, J. Pan, J. Leacock, A. R. Lee, V. Tadevosyan, D. Gaskell, Y. Liang, R. Michaels, M. M. Dalton, D.J. Harrison, A.K. Opper, J. Grames, M. McDonald, S. Kowalski, J.C. Cornejo, W. S. Duvall, W. D. Ramsay, A. Asaturyan, J. Leckey, K. Grimm, J. W. Martin, B. Stokes, P. M. King, Michael Gericke, K. E. Mesick, H. Mkrtchyan, E. Ihloff, J. A. Magee, Nadeem A. Khan, L. Lee, J. Kelsey, Trent Allison, Jay Benesch, S. Yang, D. T. Spayde, B. Waidyawansa, D.B. Brown, S. Covrig Dusa, Dipangkar Dutta, W. R. Falk, R. Silwal, A. Subedi, Vladimir Nelyubin, J. Bessuille, D. G. Meekins, R. T. Jones, J. Hansknecht, Nuruzzaman, W. T. H. van Oers, K.D. Finelli, Michael Pitt, J.R. Echols, D. S. Armstrong, G. R. Smith, Douglas Storey, M. J. McHugh, M. H. Shabestari, J. Musson, K. A. Dow, L. Z. Ndukum, Wouter Deconinck, W.R. Roberts, William A. Tobias, and B. S. Cavness
- Subjects
Physics ,Nuclear and High Energy Physics ,business.industry ,Compton scattering ,Collimator ,Electron ,Helicity ,law.invention ,Nuclear physics ,Optics ,Beamline ,law ,Scintillation counter ,Cathode ray ,Physics::Accelerator Physics ,Parity violation ,Electron scattering ,Liquid hydrogen target ,business ,Instrumentation ,Cherenkov radiation - Abstract
The Jefferson Lab Q weak experiment determined the weak charge of the proton by measuring the parity-violating elastic scattering asymmetry of longitudinally polarized electrons from an unpolarized liquid hydrogen target at small momentum transfer. A custom apparatus was designed for this experiment to meet the technical challenges presented by the smallest and most precise e → p asymmetry ever measured. Technical milestones were achieved at Jefferson Lab in target power, beam current, beam helicity reversal rate, polarimetry, detected rates, and control of helicity-correlated beam properties. The experiment employed 180 μA of 89% longitudinally polarized electrons whose helicity was reversed 960 times per second. The electrons were accelerated to 1.16 GeV and directed to a beamline with extensive instrumentation to measure helicity-correlated beam properties that can induce false asymmetries. Moller and Compton polarimetry were used to measure the electron beam polarization to better than 1%. The electron beam was incident on a 34.4 cm liquid hydrogen target. After passing through a triple collimator system, scattered electrons between 5.8° and 11.6° were bent in the toroidal magnetic field of a resistive copper-coil magnet. The electrons inside this acceptance were focused onto eight fused silica Cherenkov detectors arrayed symmetrically around the beam axis. A total scattered electron rate of about 7 GHz was incident on the detector array. The detectors were read out in integrating mode by custom-built low-noise pre-amplifiers and 18-bit sampling ADC modules. The momentum transfer Q 2 =0.025 GeV 2 was determined using dedicated low-current ( ~ 100 pA ) measurements with a set of drift chambers before (and a set of drift chambers and trigger scintillation counters after) the toroidal magnet.
- Published
- 2015
16. Qweak: First Direct Measurement of the Proton’s Weak Charge
- Author
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J. R. Hoskins, V. Tadevosyan, J. Diefenbach, K. Johnston, J. Birchall, S.A. Page, D. S. Armstrong, M. J. McHugh, J. Mei, H. Nuhait, C. A. Davis, M. Elaasar, Juliette Mammei, T. Averett, Wouter Deconinck, J. A. Magee, P. Wang, S. Yang, G.R. Smith, W. R. Falk, P. Zang, H. Mkrtchyan, W. T. H. van Oers, D. G. Meekins, J. Pan, F. Guo, J. Roche, Vladimir Nelyubin, W.D. Ramsay, J. Beaufait, B. Sawatzky, Fatiha Benmokhtar, M.L. Pitt, D. C. Jones, N. Morgan, R. Suleiman, N. Simicevic, V. Tvaskis, R. Michaels, Michael Gericke, B. Waidyawansa, Roger Carlini, J. Leckey, T. A. Forest, R. T. Jones, Jay Benesch, J. M. Finn, J. Balewski, M. M. Dalton, J. Grames, L. Lee, Jean-Francois Rajotte, Dipangkar Dutta, S. Kowalski, L. Z. Ndukum, W. S. Duvall, D. J. Mack, J. W. Martin, A.K. Opper, M. Kargiantoulakis, S.A. Wood, T. Seva, P. Solvignon, G. D. Cates, V. M. Gray, Jongmin Lee, K. Grimm, S. Covrig, A. R. Lee, J. Leacock, R. Mahurin, D.T. Spayde, R. Silwal, A. Mkrtchyan, S.K. Phillips, A. Asaturyan, S. Zhamkochyan, S. MacEwan, E. Korkmaz, J.C. Cornejo, K. E. Myers, P. M. King, K. Bartlett, Darko Androić, A. Subedi, J. A. Dunne, Amrendra Narayan, R. Subedi, D. Gaskell, K.D. Paschke, A. Micherdzinska, M.H. Shabestari, M. K. Jones, W.A. Tobias, C. Gal, R. S. Beminiwattha, M. Poelker, Ross D. Young, J. F. Dowd, and S.P. Wells
- Subjects
Physics ,Particle physics ,Proton ,010308 nuclear & particles physics ,QC1-999 ,media_common.quotation_subject ,Hadron ,Charge (physics) ,Elementary particle ,7. Clean energy ,01 natural sciences ,Asymmetry ,Standard Model ,Nuclear physics ,0103 physical sciences ,Physics::Accelerator Physics ,Grand Unified Theory ,Nuclear Experiment ,010306 general physics ,Nucleon ,media_common - Abstract
The Q weak experiment, which took data at Jefferson Lab in the period 2010 - 2012, will precisely determine the weak charge of the proton by measuring the parity-violating asymmetry in elastic e-p scattering at 1.1 GeV using a longitudinally polarized electron beam and a liquid hydrogen target at a low momentum transfer of Q 2 = 0.025 (GeV/c)2 . The weak charge of the proton is predicted by the Standard Model and any significant deviation would indicate physics beyond the Standard Model. The technical challenges and experimental apparatus for measuring the weak charge of the proton will be discussed, as well as the method of extracting the weak charge of the proton. The results from a small subset of the data, that has been published, will also be presented. Furthermore an update will be given of the current status of the data analysis.
- Published
- 2017
17. Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm
- Author
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Cody Reeves, Desh Ranjan, Sabbir Ahmed Khan, A. P. Freyberger, Balsa Terzic, Jay Benesch, Geoffrey Krafft, and Alicia Hofler
- Subjects
Physics ,Nuclear and High Energy Physics ,Physics and Astronomy (miscellaneous) ,010308 nuclear & particles physics ,Energy management ,Particle accelerator ,Surfaces and Interfaces ,01 natural sciences ,Linear particle accelerator ,law.invention ,law ,Proof of concept ,0103 physical sciences ,Genetic algorithm ,Electronic engineering ,lcsh:QC770-798 ,lcsh:Nuclear and particle physics. Atomic energy. Radioactivity ,Radio frequency ,Simultaneous optimization ,Heat load ,010306 general physics - Abstract
In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab's Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.
- Published
- 2014
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