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46 results on '"Gallardo, Juan C."'

1. A Possible Hybrid Cooling Channel for a Neutrino Factory

Author

Gallardo, Juan C. and Zisman, Michael S.

Subjects
Physics - Accelerator Physics, High Energy Physics - Phenomenology
Abstract

A Neutrino Factory requires an intense and well-cooled (in transverse phase space) muon beam. We discuss a hybrid approach for a linear 4D cooling channel consisting of high-pressure gas-filled RF cavities- potentially allowing high gradients without breakdown- and discrete LiH absorbers to provide the necessary energy loss that results in the required muon beam cooling. We report simulations of the channel performance and its comparison with the vacuum case; we also briefly discuss technical and safety issues associated with cavities filled with high-pressure hydrogen gas. Even with additional windows that might be needed for safety reasons, the channel performance is comparable to that of the original, all-vacuum Feasibility Study 2a channel on which our design is based. If tests demonstrate that the gas-filled RF cavities can operate effectively with an intense beam of ionizing particles passing through them, our approach would be an attractive way of avoiding possible breakdown problems with a vacuum RF channel., Comment: 3 pages, 9 figures; submitted to IPAC10, The First International Particle Accelerator Conference, May 23-28, 2010

Published
2010

2. Thoughts On Incorporating HPRF In A Linear Cooling Channel

Author

Gallardo, Juan C. and Zisman, Michael S.

Subjects
Physics - Accelerator Physics
Abstract

We discuss a possible implementation of high-pressure gas-filled RF (HPRF) cavities in a linear cooling channel for muons and some of the technical issues that must be dealt with. The approach we describe is a hybrid approach that uses high-pressure hydrogen gas to avoid cavity breakdown, along with discrete LiH absorbers to provide the majority of the energy loss. Initial simulations show that the channel performs as well as the original vacuum RF channel while potentially avoiding the degradation in RF gradient associated with the strong magnetic field in the cooling channel., Comment: 5 pages, 8 figures, submitted to Proceedings of NUFACT09

Published
2009
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3. rf Breakdown with and without External Magnetic Fields

Author

Palmer, Robert B., Fernow, Richard C., Gallardo, Juan C., Stratakis, Diktys, and Li, Derun

Subjects
Physics - Accelerator Physics
Abstract

Neutrino Factories and Muon Colliders' cooling lattices require both high gradient rf and strong focusing solenoids. Experiments have shown that there may be serious problems operating rf in the required magnetic fields. The use of high pressure gas to avoid these problems is discussed, including possible loss problems from electron and ion production by the passage of an ionizing beam. It is also noted that high pressure gas cannot be used in later stages of cooling for a muon collider. Experimental observations using vacuum rf cavities in magnetic fields are discussed, current published models of breakdown with and without magnetic fields are summarized, and some of their predictions compared with observations. A new theory of magnetic field dependent breakdown is presented. It is proposed that electrons emitted by field emission on asperities on one side of a cavity are focused by the magnetic field to the other side where they melt the cavity surface in small spots. Metal is then electrostatically drawn from the molten spots, becomes vaporized and ionized by field emission from the remaining damage and cause breakdown. The theory is fitted to existing 805 MHz data and predictions are made for performance at 201 MHz. The model predicts breakdown gradients significantly below those specified for either the International Scoping Study (ISS) Neutrino Factory or a Muon Collider. Possible solutions to these problems are discussed, including designs for `magnetically insulated rf' in which the cavity walls are designed to be parallel to a chosen magnetic field contour line and consequently damage from field emission is suppressed. An experimental program to study these problems and their possible solution is outlined., Comment: 16 pages, 21 figures, 2 tables

Published
2008

4. Muon Dynamics in a Toroidal Sector Magnet

Author

Gallardo, Juan C., Fernow, Richard C., and Palmer, Robert B.

Subjects
Physics - Accelerator Physics
Abstract

We present a Hamiltonian formulation of muon dynamics in toroidal sector solenoids (bent solenoids), Comment: format aipproc.cls; aipproc.sty; 7 pages, two figures (*.ps). Submitted to the Proceedings of the 4th International Conference on Physics Potential and Development of mu-mu Colliders, San Francisco, Dec. 1997

Published
1998
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5. Final Focus System for a Muon Collider: A Test Model

Author

Gallardo, Juan C. and Palmer, Robert B.

Subjects
Physics - Accelerator Physics
Abstract

The present scenario for a high luminosity 4 TeV on center of mass muon collider requires a beta function =3 mm at the interaction point. We discuss a test model of a basic layout which satisfies the requirements although it is not fully realistic., Comment: 9 pages, uses REVTEX macros. Submitted to the Proceedings of the Symposium on Physics Potential and Development of mu^+-mu^- Colliders, San Francisco, CA. Suppl. of the journal Nuclear Physics B

Published
1996

6. Muon Transverse Ionization Cooling: Stochastic Approach

Author

Fernow, Richard C. and Gallardo, Juan C.

Subjects
Physics - Accelerator Physics
Abstract

Transverse ionization cooling of muons is modeled as a Brownian motion of the muon beam as it traverses a Li or Be rod. A Langevin like equation is written for the free particle case (no external transverse magnetic field) and for the case of a harmonically bound beam in the presence of a focusing magnetic field. We demonstrate that the well known muon cooling equations for short-absorbers can be extrapolated to the useful case of a long absorber rod with a focusing magnetic field present., Comment: Latex uses revtex, 9 pages; submitted to Phys. Rev E

Published
1995
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10. Free-electron laser intracavity light as a source of hard x-ray production by Compton backscattering

Author

Dattoli, G., Gallardo, Juan C., and Ottaviani, P.L.

Subjects
Backscattering -- Analysis, Free electron lasers -- Research, Physics
Abstract

Dynamical behavior is typical of X-ray production based on Compton backscattering process (CBP) that denotes the evolution and growth of the intracavity free-electron laser (FEL) radiation. The rate of scattered photons shoots up until the FEL reaches its saturation and the FEL-stimulated energy spread results in continuous degradation of the brightness of the X-rays. X-ray CBP intracavity FEL sources potentiate intracavity radiation which limits the brightness of the X-ray source. High power conventional lasers overcome these constraints. These devices offer larger CBP brightness.

Published
1994

11. Random errors in iron-dominated microundulators.

Author

Gallardo, Juan C.

Subjects
*MATHEMATICAL models, *WIGGLER magnets, *MANUFACTURING processes
Abstract

Presents a study that described a mathematical model of errors in iron-dominated microundulators introduced by manufacturing/machining tolerances of the pole pieces. Description of the model; Information on error fields; Conclusions.

Published
1991
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12. Inverse Cerenkov Acceleration and Inverse Free-Electron Laser Experimental Results for Staged Electron Laser Acceleration

Author

Campbell, Lora P., Dilley, Christian E., Gottschalk, Stephen C., Kimura, Wayne D., Quimby, David C., Steinhauer, Loren C., Babzien, Marcus, Ben-Zvi, Ilan, Gallardo, Juan C., Kusche, Karl P. Jr., Pogorelksy, Igor V., Skaritka, John R., Steenbergen, Arie van, Yakimenko, Vitlay E., Cline, David B., He, Ping, Liu, Yabo, and Pantell, Richard H.

Subjects
Carbon dioxide lasers -- Research, Electron accelerators -- Research, Free electron lasers -- Research, Particle beams -- Measurement, Linear accelerators -- Research, Magnets, Permanent -- Usage, Acceleration (Mechanics) -- Research, Business, Chemistry, Electronics, Electronics and electrical industries
Abstract

The goal of the staged electron laser acceleration (STELLA) experiment is to demonstrate staging of the laser acceleration process whereby an inverse free electron laser (IFEL) will be used to prebunch the electrons, which are then accelerated in an inverse Cerenkov accelerator (ICA). As preparation for this experiment, a new permanent magnet wiggler for the IFEL was constructed and the ICA system was modified. Both systems have been tested on a new beamline specifically built for STELLA. The improved electron beam (e-beam) with its very low emittance (0.8 mm-mrad normalized) enabled focusing the e-beam to an average radius (1[Sigma]) of 65 [micro]m within the ICA interaction region. This small e-beam focus greatly enhanced the ICA process and resulted in electron energy spectra that have demonstrated the best agreement to date in both overall shape and magnitude with the model predictions. The electron energy spectrum using the new wiggler in the IFEL was also measured. These results will be described as well as future improvements to the STELLA experiment. Index Terms--Carbon dioxide lasers, electron accelerators, electron linear accelerators, inverse Cerenkov accelerators, inverse free electron laser, laser accelerators, linear accelerators, particle beam measurements.

Published
2000

21. Recent progress in neutrino factory and muon collider research within the Muon Collaboration

Author

Alsharo’a, Mohammad M., primary, Ankenbrandt, Charles M., additional, Atac, Muzaffer, additional, Autin, Bruno R., additional, Balbekov, Valeri I., additional, Barger, Vernon D., additional, Benary, Odette, additional, Bennett, J. Roger J., additional, Berger, Michael S., additional, Berg, J. Scott, additional, Berz, Martin, additional, Black, Edgar L., additional, Blondel, Alain, additional, Bogacz, S. Alex, additional, Bonesini, M., additional, Bracker, Stephen B., additional, Bross, Alan D., additional, Bruno, Luca, additional, Buckley-Geer, Elizabeth J., additional, Caldwell, Allen C., additional, Campanelli, Mario, additional, Cassel, Kevin W., additional, Catanesi, M. Gabriela, additional, Chattopadhyay, Swapan, additional, Chou, Weiren, additional, Cline, David B., additional, Coney, Linda R., additional, Conrad, Janet M., additional, Corlett, John N., additional, Cremaldi, Lucien, additional, Cummings, Mary Anne, additional, Darve, Christine, additional, DeJongh, Fritz, additional, Drozhdin, Alexandr, additional, Drumm, Paul, additional, Elvira, V. Daniel, additional, Errede, Deborah, additional, Fabich, Adrian, additional, Fawley, William M., additional, Fernow, Richard C., additional, Ferrario, Massimo, additional, Finley, David A., additional, Fisch, Nathaniel J., additional, Fukui, Yasuo, additional, Furman, Miguel A., additional, Gabriel, Tony A., additional, Galea, Raphael, additional, Gallardo, Juan C., additional, Garoby, Roland, additional, Garren, Alper A., additional, Geer, Stephen H., additional, Gilardoni, Simone, additional, Van Ginneken, Andreas J., additional, Ginzburg, Ilya F., additional, Godang, Romulus, additional, Goodman, Maury, additional, Gosz, Michael R., additional, Green, Michael A., additional, Gruber, Peter, additional, Gunion, John F., additional, Gupta, Ramesh, additional, Haines, John R, additional, Hanke, Klaus, additional, Hanson, Gail G., additional, Han, Tao, additional, Haney, Michael, additional, Hartill, Don, additional, Hartline, Robert E., additional, Haseroth, Helmut D., additional, Hassanein, Ahmed, additional, Hoffman, Kara, additional, Holtkamp, Norbert, additional, Holzer, E. Barbara, additional, Johnson, Colin, additional, Johnson, Rolland P., additional, Johnstone, Carol, additional, Jungmann, Klaus, additional, Kahn, Stephen A., additional, Kaplan, Daniel M., additional, Keil, Eberhard K., additional, Kim, Eun-San, additional, Kim, Kwang-Je, additional, King, Bruce J., additional, Kirk, Harold G., additional, Kuno, Yoshitaka, additional, Ladran, Tony S., additional, Lau, Wing W., additional, Learned, John G., additional, Lebedev, Valeri, additional, Lebrun, Paul, additional, Lee, Kevin, additional, Lettry, Jacques A., additional, Laveder, Marco, additional, Li, Derun, additional, Lombardi, Alessandra, additional, Lu, Changguo, additional, Makino, Kyoko, additional, Malkin, Vladimir, additional, Marfatia, D., additional, McDonald, Kirk T., additional, Mezzetto, Mauro, additional, Miller, John R., additional, Mills, Frederick E., additional, Mocioiu, I., additional, Mokhov, Nikolai V., additional, Monroe, Jocelyn, additional, Moretti, Alfred, additional, Mori, Yoshiharu, additional, Neuffer, David V., additional, Ng, King-Yuen, additional, Norem, James H., additional, Onel, Yasar, additional, Oreglia, Mark, additional, Ozaki, Satoshi, additional, Padamsee, Hasan, additional, Pakvasa, Sandip, additional, Palmer, Robert B., additional, Parker, Brett, additional, Parsa, Zohreh, additional, Penn, Gregory, additional, Pischalnikov, Yuriy, additional, Popovic, Milorad B., additional, Qian, Zubao, additional, Radicioni, Emilio, additional, Raja, Rajendran, additional, Ravn, Helge L., additional, Reed, Claude B., additional, Reginato, Louis L., additional, Rehak, Pavel, additional, Rimmer, Robert A., additional, Roberts, Thomas J., additional, Roser, Thomas, additional, Rossmanith, Robert, additional, Samulyak, Roman V., additional, Scanlan, Ronald M., additional, Schlenstedt, Stefan, additional, Schwandt, Peter, additional, Sessler, Andrew M., additional, Shaevitz, Michael H., additional, Shrock, Robert, additional, Sievers, Peter, additional, Silvestrov, Gregory I., additional, Simos, Nick, additional, Skrinsky, Alexander N., additional, Solomey, Nickolas, additional, Spampinato, Philip T., additional, Spentzouris, Panagiotis, additional, Stefanski, R., additional, Stoltz, Peter, additional, Stumer, Iuliu, additional, Summers, Donald J., additional, Teng, Lee C., additional, Thieberger, Peter A., additional, Tigner, Maury, additional, Todosow, Michael, additional, Tollestrup, Alvin V., additional, Torun, Yağmur, additional, Trbojevic, Dejan, additional, Usubov, Zafar U., additional, Vsevolozhskaya, Tatiana A., additional, Wah, Yau, additional, Wang, Chun-xi, additional, Wang, Haipeng, additional, Weggel, Robert J., additional, Whisnant, K., additional, Willen, Erich H., additional, Wilson, Edmund J. N., additional, Winn, David R., additional, Wurtele, Jonathan S., additional, Wu, Vincent, additional, Yokoi, Takeichiro, additional, Yoon, Moohyun, additional, York, Richard, additional, Yu, Simon, additional, Zeller, Al, additional, Zhao, Yongxiang, additional, and Zisman, Michael S., additional

Published
2003
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22. RF Breakdown in Magnetic Fields: Previous Work, Recent Theory, and Future Plans.

Author

Stratakis, Diktys, Gallardo, Juan C., and Palmer, Robert B.

Subjects
*ELECTRON emission, *MAGNETIC fields, *OSCILLATIONS, *NEUTRINOS, *NUCLEAR physics
Abstract

Recent experiments on the breakdown of rf cavities revealed severe surface damage and a reduction of the maximum accelerating gradient after operation in an external magnetic field. This finding implies the possibility of serious problems for cooling lattices wherein rf cavities and external magnetic fields coexist, such as those of the proposed neutrino factory and muon collider. An experimental program that could study those problems and their possible solutions is discussed. Emphasis is given to a magnetically insulated cavity design in which the walls are parallel to the magnetic field lines and consequently damage from field emission is expected to be suppressed. [ABSTRACT FROM AUTHOR]

Published
2010
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23. Thoughts on Incorporating HPRF in a Linear Cooling Channel.

Author

Gallardo, Juan C. and Zisman, Michael S.

Subjects
*MUONS, *ENERGY dissipation, *OSCILLATIONS, *NUCLEAR physics, *MAGNETIC fields
Abstract

We discuss a possible implementation of high-pressure gas-filled RF (HPRF) cavities in a linear cooling channel for muons and some of the technical issues that must be dealt with. The approach we describe is a hybrid approach that uses high-pressure hydrogen gas to avoid cavity breakdown, along with discrete LiH absorbers to provide the majority of the energy loss. Initial simulations show that the channel performs as well as the original vacuum RF channel while potentially avoiding the degradation in RF gradient associated with the strong magnetic field in the cooling channel. [ABSTRACT FROM AUTHOR]

Published
2010
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25. Status of muon collider research and development and future plans

Author

Ankenbrandt, Charles M., primary, Atac, Muzaffer, additional, Autin, Bruno, additional, Balbekov, Valeri I., additional, Barger, Vernon D., additional, Benary, Odette, additional, Berg, J. Scott, additional, Berger, Michael S., additional, Black, Edgar L., additional, Blondel, Alain, additional, Bogacz, S. Alex, additional, Bolton, T., additional, Caspi, Shlomo, additional, Celata, Christine, additional, Chou, Weiren, additional, Cline, David B., additional, Corlett, John, additional, Cremaldi, Lucien, additional, Diehl, H. Thomas, additional, Drozhdin, Alexandr, additional, Fernow, Richard C., additional, Finley, David A., additional, Fukui, Yasuo, additional, Furman, Miguel A., additional, Gabriel, Tony, additional, Gallardo, Juan C., additional, Garren, Alper A., additional, Geer, Stephen H., additional, Ginzburg, Ilya F., additional, Green, Michael A., additional, Guler, Hulya, additional, Gunion, John F., additional, Gupta, Ramesh, additional, Han, Tao, additional, Hanson, Gail G., additional, Hassanein, Ahmed, additional, Holtkamp, Norbert, additional, Johnson, Colin, additional, Johnstone, Carol, additional, Kahn, Stephen A., additional, Kaplan, Daniel M., additional, Kim, Eun San, additional, King, Bruce J., additional, Kirk, Harold G., additional, Kuno, Yoshitaka, additional, Lebrun, Paul, additional, Lee, Kevin, additional, Lee, Peter, additional, Li, Derun, additional, Lissauer, David, additional, Littenberg, Laurence S., additional, Lu, Changguo, additional, Luccio, Alfredo, additional, Lykken, Joseph D., additional, McDonald, Kirk T., additional, McInturff, Alfred D., additional, Miller, John R., additional, Mills, Frederick E., additional, Mokhov, Nikolai V., additional, Moretti, Alfred, additional, Mori, Yoshiharu, additional, Neuffer, David V., additional, Ng, King-Yuen, additional, Noble, Robert J., additional, Norem, James H., additional, Onel, Yasar, additional, Palmer, Robert B., additional, Parsa, Zohreh, additional, Pischalnikov, Yuriy, additional, Popovic, Milorad, additional, Prebys, Eric J., additional, Qian, Zubao, additional, Raja, Rajendran, additional, Reed, Claude B., additional, Rehak, Pavel, additional, Roser, Thomas, additional, Rossmanith, Robert, additional, Scanlan, Ronald M., additional, Sessler, Andrew M., additional, Shadwick, Brad, additional, Shu, Quan-Sheng, additional, Silvestrov, Gregory I., additional, Skrinsky, Alexandr N., additional, Smith, Dale, additional, Spentzouris, Panagiotis, additional, Stefanski, Ray, additional, Striganov, Sergei, additional, Stumer, Iuliu, additional, Summers, Don, additional, Tcherniatine, Valeri, additional, Teng, Lee C., additional, Tollestrup, Alvin V., additional, Torun, Yağmur, additional, Trbojevic, Dejan, additional, Turner, William C., additional, Vahsen, Sven E., additional, Van Ginneken, Andreas, additional, Vsevolozhskaya, Tatiana A., additional, Wan, Weishi, additional, Wang, Haipeng, additional, Weggel, Robert, additional, Willen, Erich H., additional, Wilson, Edmund J. N., additional, Winn, David R., additional, Wurtele, Jonathan S., additional, Yokoi, Takeichiro, additional, Zhao, Yongxiang, additional, and Zolotorev, Max, additional

Published
1999
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35. Integral equation for the laser field: Multimode description of a free electron laser oscillator

Author

Gallardo, Juan C., Dattoli, G., Renieri, Alberto, and Hermsen, T.

Abstract

In the first part of this article we present a one-dimensional multimode theory of a free electron laser. We show that the evolution of the laser field in a single pass through the undulator satisfies an integral equation. The formulation is exact, describing saturation and both low and high gain regime of a long-pulse free electron laser.

Published
1988
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46. NF-kappaB does not influence the induction of apoptosis by Ukrain.

Author

Mendoza J, Zamora R, Gallardo JC, Ceballos G, Aldana A, Espinosa M, Maldonado V, and Melendez-Zajgla J

Subjects
B-Cell Lymphoma 3 Protein, Caspase 3 analysis, Caspase 3 metabolism, Caspase 9 analysis, Caspase 9 metabolism, Cell Line, Tumor, Gene Expression, Genes, Reporter, Humans, I-kappa B Kinase antagonists & inhibitors, I-kappa B Kinase genetics, I-kappa B Kinase metabolism, NF-kappa B agonists, NF-kappa B analysis, Neoplasms genetics, Neoplasms pathology, Proto-Oncogene Proteins antagonists & inhibitors, Proto-Oncogene Proteins genetics, RNA, Small Interfering genetics, RNA, Small Interfering pharmacology, Transcription Factors antagonists & inhibitors, Transcription Factors genetics, Antineoplastic Agents pharmacology, Apoptosis, Berberine Alkaloids pharmacology, NF-kappa B metabolism, Neoplasms metabolism, Phenanthridines pharmacology
Abstract

Ukrain is a reaction product of different alkaloids from Chelidonium majus L. (celandine) conjugated with thiophosphoric acid. It has immunoregulatory effects on T lymphocyte subsets and cytotoxic and cytostatic effects on various malignant cells. Although Ukrain has been reported to induce alterations in the cell cycle and tubulin polymerization, the specific cellular target has not been described. Since antineoplasic agents induce NF-kappaB and their effects are regulated by this transcription factor, we investigated its possible participation in the apoptotic effects of Ukrain. Ukrain induced apoptosis in a panel of cancer cell lines by activating the intrinsic cell death pathway, as demonstrated by the cleavage of caspase 9 and the upregulation and cleavage of caspase 3. The effect was reversible, since long exposures (24 hours or more) were needed, as verified by clonogenic assays. Gene reporter assays showed that Ukrain activated NF-kappa B. Nevertheless, this activation was not required for, and did not modulate, the Ukrain effect: neither blockage of activation by a dominant negative version of Ikappa-B alpha or a Bcl-3 siRNA, nor activation of the pathway by overexpression of IKK2, changed the response to the drug. In conclusion, Ukrain induced apoptosis in HeLa cervical cancer cells by activating the intrinsic pathway. In contrast to other antineoplasic drugs, the effects of Ukrain were not regulated by NF-kappa B.

Published
2006
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