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PAC 1995

Name: PAC 1995

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Date: 1995-01-01

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Created at: Fri Jul 27 23:53:34 -0700 2007

Updated at: Fri Jul 27 23:53:34 -0700 2007

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11 papers from the conference:

title: Initial operation of the UCLA plane wave transformer (PWT) linac
format: conference proceeding
conference: PAC 1995
year: 1995
10 authors: R. Zhang | P. Davis | G. Hairapetian | M. Hogan | C. Joshi | M. Lampel | S. Park | C. Pellegrini | J.B. Rosenzweig | G. Travish
abstract: We report on the initial operation of a novel compact rf linac-the plane wave transformer (PWT). The PWT is a 42 cm long, 8 cell standing-wave structure, operated at S-band, in a pi -mode. We present the properties of this linac at rf power levels from 4 MW to 8 MW and beam energy from 7 MeV to 10 MeV, measured initially using both dark current and photo-electrons. Some technical issues associated with the operation are discussed. Future improvements of the PWT, using a modified design, are also studied. (6 References).
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title: Charge and Wavelength Scaling of RF Photoinjector Designs
format: conference proceeding
conference: PAC 1995
year: September 21, 1994
2 authors: J.B. Rosenzweig | E. Colby
abstract: The optimum design of an emittance compensated rf photoinector is very complicated and time-consuming, relying heavily on multi-particle simulations without good analytical models as a guide. Emittance compensated designs which have been developed, however, can be used to generate other designs with no additional effort if the original design is scaled correctly. This paper examines the scaling of rf photoinjector design with reqpect to charge and wavelength, and presents emittance and brightness scaling laws for these variables. Parametric simulation studies are presented to illustrate these scaling laws. Deviations from scaling and practical considerations are also discussed.
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title: Design and Construction of High Brightness RF Photoinjectors for TESLA
format: conference proceeding
conference: PAC 1995
year: 1995
6 authors: E. Colby | Bharadwaj, V. | Ostiguy, J. F. | Nicol, T. | M. Conde | J.B. Rosenzweig
abstract: The design, construction and testing of a high brightness high bunch charge RF photoinjectormatching the requirements of the TESLA Test Facility is discussed. Engineering design work, the results of cold test measurements, and the planned experimental program are presented. Conceptual design work leading to an advanced high-brightness asymmetric emittance RF photoinjector for application to TESLA500 is also briefly discussed.
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title: Measurements of plasma wake-fields in the blow-out regime
format: conference proceeding
conference: PAC 1995
year: 1995
9 authors: N. Barov | M. Conde | J.B. Rosenzweig | Schoessow, P. | Cox, G. | W. Gai | Konecny, R. | J. Power | J. Simpson
abstract: Initial results from nonlinear plasma wake-field experiments at the Argonne Wakefield Accelerator (AWA) test facility are reported. This nonlinear "blow-out" regime is characterized by the complete ejection of the plasma electrons from the beam channel. The wake-fields in this case are of notably high quality for acceleration of electrons, as the acceleration is independent of transverse position, and the focusing is linear and independent of longitudinal position within the electron depleted region, allowing self-consistent guiding of the majority of the driving electron beam. Initial measurements of the energy gain in a witness beam indicate a positive shift in its energy distribution of at least 0.5 MeV. (9 References).
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title: The UCLA compact high brightness electron accelerator
format: conference proceeding
conference: PAC 1995
year: 1995
10 authors: P. Davis | G. Hairapetian | M. Hogan | C. Joshi | M. Lampel | S. Park | C. Pellegrini | J.B. Rosenzweig | G. Travish | R. Zhang
abstract: We report the characteristics and performance of the UCLA S-band compact electron accelerator, consisting of a high brightness, 8 cm long, photo-injector with a copper cathode, followed by a 42 cm long plane wave transformer accelerating structure, delivering a beam energy of 10 MeV. The photo-electrons are produced by a 266 nm laser pulse of less than 4 ps in duration. Over time the laser induced electron emission decreases and the emission from the cathode surface becomes structured. Measurements of the quantum efficiency for Cu before and after this degradation are presented along with images of the non uniform electron emission. (8 References).
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title: Status of the UCLA high-gain infrared free electron laser
format: conference proceeding
conference: PAC 1995
year: 1995
5 authors: M. Hogan | C. Pellegrini | J.B. Rosenzweig | G. Travish | A. A. Varfolomeev
abstract: A compact, infrared (10-20 mu m), high-gain FEL is being commissioned at the Particle Beam Physics Laboratory (PBPL) at UCLA. A 60 cm long undulator with a period of 1.5 cm and an undulator parameter K-l has been built to be used in conjunction with the PBPL beam. Experiments will focus on EEL physics pertinent to proposed short wavelength devices. Of particular interest is exploration of startup from noise, self amplified spontaneous emission (SASE), beam parameter effects on gain, and output power fluctuations. Beam micro-bunching due to the FEL action will also be measured using coherent transition radiation. Here we present an overview of the relevant diagnostics, FEL simulation results and proposed experiments. (13 References).
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title: Progress on Plasma Lens Experiments at the Final Focus Test Beam
format: conference proceeding
conference: PAC 1995
year: 1995
34 authors: P. Kwok | Chen, P. | D. B. Cline | W. Barletta | Berridge, S. | Bugg, W. | Bula, C. | S. Chattopadhyay | Craddock, W. | Hsu, I. | R. Iverson | T. Katsouleas | Lai, P. | Leemans, W. | Liou, R. | McDonald, K. T. | D. Meyerhofer | Nakajima, K. | Nakanishi, H. | Ng, C. K. | Nishida, Y. | Norem, J. | A. Ogata | J.B. Rosenzweig | Ross, M. | Sessler, A. M. | Shintake, T. | Spencer, J. | Su, J. J. | Weidemann, A. W. | Westenskow, G. | D. Whittum | Williams, R. | J. Wurtele
abstract: The proposal to perform a series of plasma lens experiments at the Final Focus Test Beam at SLAC has been described earlier. We report on our progress towards validation of concepts involved in the experiments, including the laser ionized plasma production test, development of the supersonic gas jet as the plasma source, and study on focused beam size measurement techniques. Most importantly, the effects of background events due to plasma lenses in future linear collider detectors, such as that in the NLC, are studied in details and are shown to be within detector tolerances.
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title: An injector-prebuncher for a plasma electron accelerator
format: conference proceeding
conference: PAC 1995
year: 1995
5 authors: M. Lampel | C. Pellegrini | R. Zhang | C. Joshi | W. M. Fawley
abstract: Optimum operation of a plasma beat-wave or wakefield accelerator requires an injected beam consisting of a train of electron bunches separated by the plasma wavelength, with each bunch in the train having a length much shorter than the plasma wavelength, and the capability of controlling the relative phase of the electron bunches and plasma wave. The typical plasma wavelength is about 0.1 mm, requiring a bunch length of about 10 to 20 mu m, which is difficult to achieve with conventional RF based injectors. In this paper we describe an electron accelerator-buncher system based on a photoinjector and an FEL, which can satisfy the plasma accelerator requirements. (4 References).
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title: Charge and Wavelength Scaling of RF Photoinjectors: A Design Tool
format: conference proceeding
conference: PAC 1995
year: 1995
2 authors: J.B. Rosenzweig | E. Colby
abstract: The optimum design of an emittance compensated rf photoinjector is very complicated and time-consuming, relying heavily on multi-particle simulations without good analytical models as a guide. Emittance compensated designs which have been developed, however, can be used to generate other designs with no additional effort if the original design is scaled correctly. This paper examines the scaling of rf photoinjector design with respect to charge and wavelength, and presents emittance and brightness scaling laws for these variables. Parametric simulation studies are presented to illustrate these scaling laws. A practical design for the TESLA FEL rf photo-injector is developed using these scaling techiniques.
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title: Analytical model for emittance compensation in RF photo-injectors
format: conference proceeding
conference: PAC 1995
year: 1995
2 authors: L. Serafini | J.B. Rosenzweig
abstract: In this paper we present a new model to represent analytically the transverse beam dynamics in RF photo-injectors. It consists basically of an enhanced Kim's model, with incorporation of RF ponderomotive focusing effects, external magnetic focusing and a perturbative treatment of space charge along the beam envelope. Applying the resulting formulas it is possible to predict with high accuracy the transverse beam envelope behaviour in a multi-cell RF gun, as well as the operating conditions to achieve space charge emittance compensation according to Carlsten's scheme. The agreement with sophisticated numerical simulations is really quite satisfactory, as well as the match with experimental measurements of the predicted operating range for emittance compensation. (7 References).
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title: Measurements of the octupole-induced amplitude-dependent frequency shift in SPEAR
format: conference proceeding
conference: PAC 1995
year: 1995
5 authors: Tran, P. | C. Pellegrini | Yang, J. | M. Cornacchia | Corbett, J.
abstract: Four octupoles are used in SPEAR to provide the frequency spread for Landau damping of coupled-bunch motions at high current. With the planned implementation of a new low-emittance lattice, the effectiveness of the octupoles needs to be quantified. The recent development of a multi-dimensional turn-by-turn phase-space monitor and the availability of an accurate frequency analysis technique have made measurement of the octupole-induced amplitude-dependent frequency shift in the new SPEAR lattice possible. This paper presents the data collection and analysis procedures, and compares experimental results to model-based simulations. (5 References).
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