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Bharadwaj, V.

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Last Name: Bharadwaj

Full Name: Bharadwaj, V.

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3 papers
title: The design for the LCLS RF photoinjector
format: conference proceeding
conference: FEL 1998 20th
year: 1999
16 authors: R. Alley | Bharadwaj, V. | Clendenin, J. E. | P. Emma | Fisher, A. | Frisch, J. | Kotseroglou, T. | R. H. Miller | D. T. Palmer | Schmerge, J. F. | Sheppard, J. C. | Woodley, M. | Yeremian, A. D. | J.B. Rosenzweig | D. Meyerhofer | L. Serafini
abstract: We report on the design of the RF photoinjector of the Linac Coherent Light Source. The RF photoinjector is required to produce a single 150 MeV bunch of similar to 1 nC and similar to 100 A peak current at a repetition rate of 120 Hz with a normalized rms transverse emittance of similar to 1 pi mm-mrad. The design employs a 1.6-cell S-band RF gun with an optical spot size at the cathode of a radius of similar to 1 mm and a pulse duration with an rms sigma of similar to 3 ps. The peak RF field at the cathode is 150 MV/m with extraction 57 degrees ahead of the RF peak. A solenoidal field near the cathode allows the compensation of the initial emittance growth by the end of the injection linac. Spatial and temporal shaping of the laser pulse striking the cathode will reduce the compensated emittance even further. Also, to minimize the contribution of the thermal emittance from the cathode surface, while at the same time optimizing the quantum efficiency, the laser wavelength for a Cu cathode should be tunable around 260 nm. Following the injection linac the geometric emittance simply damps linearly with energy growth. PARMELA simulations show that this design will produce the desired normalized emittance, which is about a factor of two lower than has been achieved to date in other systems. In addition to low emittance, we also aim for laser amplitude stability of 1% in the UV and a timing jitter in the electron beam of 0.5 ps rms, which will lead to less than 10% beam intensity fluctuation after the electron bunch is compressed in the main linac.

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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: Progress towards a turn-by-turn beam profile monitor for the Fermilab Booster
format: conference proceeding
conference: Second Annual Workshop on Accelerator Instrumentation
year: 1991
4 authors: J.B. Rosenzweig | V. Bharadwaj | J. Lackey | P. Zhou
abstract: Describes the design and pre-installation testing of a turn-by-turn beam profile monitor for the Fermilab Booster. this non-intrusive monitor collects the ions created by beam particle collisions with the residual gas onto a microchannel plate (MCP) detector using a large (50-100 kV/m) clearing field, to obtain a projected image of the beam distribution in a given plane. The output of the MCP is an anode strip array which gives a 48 channel image with 1.5 mm resolution. The strip current signal is digitized on a turn-by-turn basis to potentially generate more than 16000 beam profiles in one Booster cycle. The purpose of this device is to aid in understanding the effects which drive the transverse emittance growth in the Booster, which may have time scales as short as one turn. (6 References).

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