7 papers

title:	Beam extraction studies at 900 GeV using a channeling crystal
format:	unknown
year:	2002
26 authors:	R. Carrigan | Chen, D. | G. Jackson | Mokhov, N. | C. T. Murphy | Baker, S. I. | S. A. Bogacz | D. B. Cline | Ramachandran, S. | Rhoades, J. | J. B. Rosenzweig | Asseev, A. | Biryukov, R. A. | Taratin, A. | Ellison, J. A. | Khanzadeev, A. | Prokofieva, T. | Samsonov, V. | Solodov, G. | Newberger, B. | Tsyganov, E. | Shih, H. J. | Gabella, W. | Cox, B. | Golovatyuk, V. | McManus, A.
abstract:	Luminosity-driven channeling extraction has been observed for the first time in a 900 GeV study at the Fermilab Tevatron. This experiment, Fermilab E853, demonstrated that useful TeV level beams can be extracted from a superconducting accelerator during high luminosity collider operations without unduly affecting the background at the collider detectors. Multipass extraction was found to increase the efficiency of the process significantly. The beam extraction efficiency was about 25%. Studies of time dependent effects found that the turn-to-turn structure was governed mainly by accelerator beam dynamics. Based on the results of this experiment, it is feasible to construct a parasitic 5?10 MHz proton beam from the Tevatron collider.
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title:	First observation of luminosity-driven extraction using channeling with a bent crystal
format:	unknown
year:	1998
26 authors:	R. Carrigan | Chen, D. | G. Jackson | Mokhov, N. | C. T. Murphy | Baker, S. I. | S. A. Bogacz | D. B. Cline | Ramachandran, S. | Rhoades, J. | J. B. Rosenzweig | Asseev, A. | Biryukov, R. A. | Taratin, A. | Ellison, J. A. | Khanzadeev, A. | Prokofieva, T. | Samsonov, V. | Solodov, G. | Newberger, B. | Tsyganov, E. | Shih, H. J. | Gabella, W. | Cox, B. | Golovatyuk, V. | McManus, A.
abstract:	Luminosity-driven channeling extraction has been observed for the first time using a 900 GeV circulating proton beam at the superconducting Fermilab Tevatron. The extraction efficiency was found to be about 30%. A 150 kHz beam was obtained during luminosity-driven extraction with a tolerable background rate at the collider experiments. A 900 kHz beam was obtained when the background limits were doubled. This is the highest energy at which channeling has been observed.
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title:	First Observation of Luminosity-Driven Extraction Using Channeling with a Bent Crystal
format:	preprint
year:	1998
26 authors:	Asseev, A. | Baker, S. I. | S. A. Bogacz | Biryukov, R. A. | R. A. Carrigan | Chen, D. | D. B. Cline | Cox, B. | Ellison, J. A. | Gabella, W. | Golovatyuk, V. | G. Jackson | Khanzadeev, A. | McManus, A. | Mokhov, N. | C. T. Murphy | Newberger, B. | Prokofieva, T. | Ramachandran, S. | Rhoades, J. | J. B. Rosenzweig | Samsonov, V. | Shih, H. J. | Solodov, G. | Tartin, A. | Tsyganov, E.
abstract:	Luminosity-driven channeling extraction has been observed for the first time from a 900 GeV circulating proton beam at the Fermilab Tevatron. The extraction efficiency was found to be of he order of 30%. A 150 kHz beam was obtained during luminosity-driven extraction with a tolerable background rate at the collider experiments, and a 900 kHz beam was obtained when background limits were doubled. This is the highest energy at which channeling has been observed.
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title:	First results from bent crystal extraction at the Fermilab Tevatron
format:	unknown
year:	1996
27 authors:	C. T. Murphy | R. Carrigan | Chen, D. | G. Jackson | Mokhov, N. | Shih, H. J. | Cox, B. | Golovatyuk, V. | McManus, A. | A. Bogacz | D. B. Cline | Ramachandran, S. | Rhoades, J. | J. B. Rosenzweig | Newberger, B. | Ellison, J. A. | Baker, S. | Sun, C. R. | Gabella, W. | Tsyganov, E. | Taratin, A. | Asseev, A. | Biryukov, V. | Khanzadeev, A. | Prokofieva, T. | Samsonov, V. | Solodov, G.
abstract:	First results from Fermilab Experiment 853 are presented. E853 is an experiment to test the feasibility and efficiency of extracting a low-intensity beam from the halo of the Tevatron using channeling in a bent silicon crystal. The motivation of the experiment is to apply crystal extraction to trans-TeV accelerators like the LHC. Extensive simulation work has been carried out. Two accelerator operating modes have been developed for crystal studies, ''kick'' mode and diffusion mode. Results from the first successful extraction in kick mode are presented.
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title:	Plasma Lens Experiments at the Final Focus Test Beam
format:	conference procceeding
conference:
year:	1995
33 authors:	Lieu, R. | Barletta, W. | S. Chattopadhyay | Chen, P. | D. B. Cline | Craddock, W. | Gabella, W. | Hsu, I. | R. Iverson | T. Katsouleas | P. Kwok | Lai, P. | Leemans, W. | Liou, R. | D. Meyerhofer | Nakajima, K. | Nakanishi, H. | Ng, C. K. | Nishida, Y. | Norem, J. | Ogata, A. | Rajagopalan, S. | Shintake, T. | J. B. Rosenzweig | Ross, M. | Sessler, A. | Spencer, J. | Su, J. J. | Walker, N. | Westenskow, G. | D. Whittum | Williams, R. | J. Wurtele
abstract:	We intend to carry out a series of plasma lens experiments at the Final Focus Test Beam facility at SLAC. These experiments will be the first to study the focusing of particle beams by plasma focusing devices in the parameter regime of interest for high energy colliders, and is expected to lead to plasma lens designs capable of unprecedented spot sizes. Plasma focusing of positron beams will be attempted for the first time. We will study the effects of lens aberrations due to various lens imperfections. Several approaches will be applied to create the plasma required including laser ionization and beam induced tunneling ionization of a working gas - the latter which has never been observed before. The compactness of our device should prove to be of interest for applications at the SLC and the next generation linear colliders.
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title:	Extraction from TeV-Range Accelerators Using Bent Crystal Channeling
format:	unknown
year:	1994
45 authors:	R. A. Carrigan | Chen, D. | P. Colestock | Herrup, D. | Goderre, G. | G. Jackson | C. T. Murphy | Stefanski, R. | Baker, S. | Mokhov, N. | Parker, B. | Shih, H. J. | Soundranayagam, R. | Toohig, T. | Peggs, S. | Sun, C. R. | Boden, A. | D. B. Cline | Gabella, W. | Ramachandran, S. | Rhoades, J. | J. B. Rosenzweig | Arenton, M. | Conetti, S. | Cox, B. | Dukes, D. | Golovatyuk, V. | McManus, A. | Nelson, K. | Norem, B. | Newberger, B. | Ellison, J. A. | Erwin, A. | Rossmanith, R. | Kovalenko, A. | Taratin, A. | Malakhov, N. | Tsyganov, E. | Bavizhev, M. | Biryukov, V. | M. Maslov | Khanzadeev, A. | Prokofieva, T. | Samsonov, V. | Solodov, G.
abstract:	Plans and first results from Fermilab Experiment 853 are presented. E853 is an experiment to test the feasibility and efficiency of extracting a low-intensity beam from the halo of the Tevatron using channeling in a bent silicon crystal. The motivation of the experiment is to apply crystal extraction to trans-TeV accelerators like the LHC. Channeling developments related to crystal extraction and some early results from accelerator studies at the Tevatron are presented.
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title:	RF Voltage Modulation at Discrete Frequencies, for Application to Proton Extraction Using Crysal Channeling
format:	conference procceeding
conference:	1993 Particle Accelerator Conference
year:	1993
4 authors:	Gabella, W. | J. B. Rosenzweig | Kick, R. | Peggs, S.
abstract:	RF voltage modulation at a finite number of discrete frequencies is described in a Hamiltonian framework. The theory is applied to the problem of parasitic extraction of protons from a circulating beam in a high energy hadron collider, using a bent crystal as a thin ?septum? extraction element. Three modes of employing discrete resonances are discussed: a strong, single drive resonance which may be used to excite protons to hit, deep within the crystal; a single resonance ramped in such a manner that the island can carry trapped particles from low to high amplitudes; and overlapping resonances to create a chaotic band for separating the moving island and the large amplitude island. Simulations are used to confirm the expected dynamics, and finally a prototypical extraction scheme is described.
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