Initial measurements of the UCLA rf photoinjector

Hartman, S.; Barov, N.; Pellegrini, C.; Park, S.; Rosenzweig, James; Travish, G.; Zhang, R.; Clayton, C. E.; Davis, P.; Everett, Matthew J.; Joshi, C.; Hairapetian, G.

doi:10.1016/0168-9002(94)91305-6

Cited by 23 publications

(12 citation statements)

References 5 publications

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“…Previous photocathode RF gun experiments have operated at 3 GHz or below [2][3][4][5][6][7][8][9][10], though an RF gun experiment at 8.5 GHz is currently under development [11]. There has also been much theoretical work in the study of RF guns in recent years [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical investigations of a 17GHz RF gun

Brown

Trotz

Kreischer

et al. 1999

Nuclear Instruments and Methods in Physics Research Section A:

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We report on experimental and theoretical investigations of a 17 GHz RF photocathode electron gun. This is the first photocathode electron gun to operate at a frequency above 2.856 GHz. The 1.5 cell, π−mode, copper cavity was tested with 50 ns pulses from a 17.150 GHz klystron amplifier built by Haimson Research Corp. A Bragg filter was used at the RF gun to reduce the reflection of parasitic modes back into the klystron. Coupling hole theory in conjunction with cold test measurements was used to determine the field profile in the RF gun. The particle in cell code MAGIC as well as coupled envelope equations were used to simulate the beam dynamics in the RF gun. With power levels of 4 MW, the on axis electric field at the cathode exceeds 300 MV/m, corresponding to an average accelerating gradient of 200 MV/m over the first half cell of the gun. Breakdown was observed at power levels above 5 MW. Electron bunches were produced by 20 µJ, 1 ps UV laser pulses impinging on the RF gun copper photocathode and were measured with a Faraday cup to have up to 0.1 nC of charge. This corresponds to a peak current of about 100 A, and a density at the cathode of 8.8 kA/cm 2 . Multiple output electron bunches were obtained for multiple laser pulses incident on the cathode. Phase scans of laser induced electron emission reveal an overall phase stability of better than ±20°, corresponding to ±3 ps synchronization of the laser pulses to the phase of the microwave field. A Browne-Buechner magnetic spectrometer indicated that the RF gun generated 1MeV electrons with a single shot rms energy spread of less than 2.5%, in good agreement with theoretical predictions.3

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Section: Introductionmentioning

confidence: 99%

Experimental and theoretical investigations of a 17GHz RF gun

Brown

Trotz

Kreischer

et al. 1999

Nuclear Instruments and Methods in Physics Research Section A:

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“…In the case of no gain the IR power will scale linearly with charge, and does not depend on other beam parameters. When there is gain, a change in charge, Q, will lead to a change in output power which we can evaluate using (1). A maximum gain of 5 would give a maximum change in the IR intensity of 4% for ∆Q/Q= +/-2.5%.…”

Section: Fluctuationsmentioning

confidence: 99%

“…The measurements have been done using the Saturnus linac [1], consisting of a 1 1/2 cell BNL photocathode RF gun, and a PWT accelerating structure [2], followed by a beam transport line and a 1.5 cm period, 0.75 Tesla peak field, Undulator Parameter of 1, 40 period undulator built at the Kurchatov Institute [3], [4]. The undulator provides focusing in both planes.…”

Section: Introductionmentioning

confidence: 99%

Measurements of high gain and noise fluctuations in a SASE free electron laser

Hogan

Anderson

Bishofberger

et al. 1998

Nuclear Instruments and Methods in Physics Research Section A:

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“…In accord with linear optics theory, the relationship between the transverse dimensions of the beam ( r x and r y ) and its emittances ( ε i nv x and ε inv y ) is described by simple expressions: (1) where p is the total particle momentum and β x ( z ) and β y ( z ) are specific functions that are uniquely determined by the optical system parameters. In the case of increasing particle energy, it is more convenient to use the so-called noninvariant emittance (or simply emittance), which diminishes in inverse proportion to momentum p and is defined as As a result, in order to investigate particle dynamics in the plane perpendicular to the beam direction (which is of particular interest from the standpoint of focusing properties of the accelerating and beam transport systems), it is necessary that information on the values of ε x and ε y be available.…”

Section: Introductionmentioning

confidence: 99%

“…Examples of applying them were presented in [1][2][3]. A feature of the first two approaches is that an aperture is used to…”

Section: Introductionmentioning

confidence: 99%

Estimating the Charged Particle Beam Parameters in View of the Space Charge Forces

2005

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A method for estimating the main parameters of a paraxial axially symmetric charged particle beam taking into account the contribution of space charge forces is described. This method is based on the general equation for a beam envelope. The data characterizing its convergence and stability for experimental errors are presented. The errors in determining the crossover position and the beam radius in the crossover do not exceed 15%, and the error in estimating the emittance depends on the relationship between the emittance and space charge forces. This method has been used to estimate the parameters of an actual electron gun with an energy of 50 keV and a current of 0.64 A. The results obtained are in good agreement with the design values. The technique described may be generalized to the case in which axial symmetry is absent.

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Initial measurements of the UCLA rf photoinjector

Cited by 23 publications

References 5 publications

Experimental and theoretical investigations of a 17GHz RF gun

Experimental and theoretical investigations of a 17GHz RF gun

Measurements of high gain and noise fluctuations in a SASE free electron laser

Estimating the Charged Particle Beam Parameters in View of the Space Charge Forces

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