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X-ray lithography sources: A review

Description: Synchrotron from dipole magnets in electron storage rings has emerged as a useful source of x-rays for lithography. To meet the need for these sources numerous groups around the world have embarked on projects to design and construct storage rings for x-ray lithography. Both conventional electromagnets as well as superconducting (SC) dipoles have been incorporated into the various designs. An overview of the worldwide effort to produce commercial x-ray sources will be presented. To better illustrate the elements involved in these sources a closer examination of the Superconducting X-ray Lithography Source Project (SXLS) at BNL will be presented. 11 refs., 1 fig., 5 tabs.
Date: January 1, 1989
Creator: Murphy, J.B.
Partner: UNT Libraries Government Documents Department

Free electron lasers for the XUV spectral region

Description: Using the system described, an electron storage ring with an undulator in a special bypass section, we can obtain high intensity coherent radiation by sending the beam through the undulator and using the FEL collective instability to produce radiation. Compared to other systems, such as an FEL oscillator or a transverse optical klystron, this system has the advantage that it does not
Date: January 1, 1984
Creator: Murphy, J.B. & Pellegrini, C.
Partner: UNT Libraries Government Documents Department

Synchrotron light source data book: Version 4, Revision 05/96

Description: This book is as its name implies a collection of data on existing and planned synchrotron light sources. The intention was to provide a compendium of tools for the design of electron storage rings as synchrotron radiation sources. The slant is toward the accelerator physicist as other booklets such as the X-Ray Data Booklet address the use of synchrotron radiation. It is hoped that the booklet serves as a pocket sized reference to facilitate back of the envelope type calculations. It contains some useful formulae in practical units and a brief description of many of the existing and planned light source lattices.
Date: May 1, 1996
Creator: Murphy, J.B.
Partner: UNT Libraries Government Documents Department

Issues and state of the art for short bunches in e{sup +}/e{sup {minus}} storage rings

Description: The potential of e{sup +}/e{sup {minus}} storage rings for producing short bunches is reviewed. We begin with a review of existing storage rings and proceed to discuss possible future developments. The effects which limit the production of short bunches in a ring are also discussed. Finally, the emission of coherent synchrotron radiation is examined.
Date: December 1, 1996
Creator: Murphy, J.B.
Partner: UNT Libraries Government Documents Department

Vacuum behavior of the x-ray lithography source

Description: Photon stimulated desorption, PSD, is the major source of the gas load in electron storage rings and therefore strongly influences both beam lifetime and beam quality. The 200 MeV compact ring at the NSLS is an ideal tool to study PSD since its energy can be varied from 60 to 200 MeV and the photoelectrons produced by synchrotron radiation can be measured in clearing electrodes installed to collect trapped ions. Using these electrodes we show: (1) photoelectrons are produced only by photons having energy above 10eV and (2) desorption is proportional to the number of photoelectrons. Using calibrated gauges we conclude that (1) time-integrated beam current of 10--20 Ampere-hours is needed for initial vacuum chamber clean-up, (2) venting the chamber to dry nitrogen has a negligible effect on subsequent desorption and (3) venting to air requires about 10 Ampere-hours of beam conditioning.
Date: January 1, 1991
Creator: Halama, H.J. & Murphy, J.B.
Partner: UNT Libraries Government Documents Department

Vacuum behavior of the x-ray lithography source

Description: Photon stimulated desorption, PSD, is the major source of the gas load in electron storage rings and therefore strongly influences both beam lifetime and beam quality. The 200 MeV compact ring at the NSLS is an ideal tool to study PSD since its energy can be varied from 60 to 200 MeV and the photoelectrons produced by synchrotron radiation can be measured in clearing electrodes installed to collect trapped ions. Using these electrodes we show: (1) photoelectrons are produced only by photons having energy above 10eV and (2) desorption is proportional to the number of photoelectrons. Using calibrated gauges we conclude that (1) time-integrated beam current of 10--20 Ampere-hours is needed for initial vacuum chamber clean-up, (2) venting the chamber to dry nitrogen has a negligible effect on subsequent desorption and (3) venting to air requires about 10 Ampere-hours of beam conditioning.
Date: December 31, 1991
Creator: Halama, H. J. & Murphy, J. B.
Partner: UNT Libraries Government Documents Department

Longitudinal Coherence Preservation and Chirp Evolution in a High Gain Laser Seeded Free Electron Laser Amplifier

Description: In this letter we examine the start-up of a high gain free electron laser in which a frequency-chirped coherent seed laser pulse interacts with a relativistic electron beam. A Green function formalism is used to evaluate the initial value problem. We have fully characterized the startup and evolution through the exponential growth regime. We obtain explicit expressions for the pulse duration, bandwidth and chirp of the amplified light and show that the FEL light remains fully longitudinally coherent.
Date: June 7, 2006
Creator: Murphy, J. B.; Wu, Juhao; Wang, X. J. & Watanabe, T.
Partner: UNT Libraries Government Documents Department

Longitudinal potential well distortion due to the synchrotron radiation wakefield

Description: The effect of the synchrotron radiation free space wakefield on the equilibrium bunch length in an electron storage ring is explored. The equilibrium bunch length, which is obtained numerically, is shown to increase for {alpha}<O and decrease for {alpha}>O.
Date: December 1, 1996
Creator: Bane, K.; Krinsky, S. & Murphy, J.B.
Partner: UNT Libraries Government Documents Department

VARIABLE MOMENTUM COMPACTION LATTICE STUDIES.

Description: The VUV storage ring at the National Synchrotron Light Source was used to study the impact of changes in the momentum compaction factors over a large range from positive to negative values. Changes in bunch length and synchrotron tune were measured versus current and RF parameters for these different lattices. By controlling both the first and second-order momentum compaction factors, a lattice was developed in which a pair of alpha buckets was created within the energy aperture of the vacuum chamber and beam was stored simultaneously in both buckets.
Date: March 29, 1999
Creator: KRAMER,S. & MURPHY,J.B.
Partner: UNT Libraries Government Documents Department

VARIABLE MOMENTUM COMPACTION LATTICE STUDIES.

Description: The VUV storage ring at the National Synchrotron Light Source was used to study the impact of changes in the momentum compaction factors over a large range from positive to negative values. Changes in bunch length and synchrotron tune were measured versus current and RF parameters for these different lattices. By controlling both the first and second-order momentum compaction factors, a lattice was developed in which a pair of alpha buckets was created within the energy aperture of the vacuum chamber and beam was stored simultaneously in both buckets.
Date: March 29, 1999
Creator: KRAMER,S. & MURPHY,J.B.
Partner: UNT Libraries Government Documents Department

Undulator based synchrotron radiation source in the 5-30 eV spectral region

Description: There has been recent interest in the utilization of high intensity radiation in the 5-30 eV spectral region. Applications include angle resolved photoemission, photochemistry, and radiation oncology. Here we present the design of a 500 MeV electron storage ring with long insertions for undulators. The ring is designed to provide an emittance of 0.1 mm-mrad, an average current of 1 Amp and an electron beam lifetime of greater than 3 hrs. The undulators operating near K{equals}1, yield 10{sup 15} ph/sec/0.1{percent} bandwidth in the fundamental. 5 refs.
Date: January 1, 1991
Creator: Zhang, Xiaohao; Murphy, J.B. & Krinsky, S.
Partner: UNT Libraries Government Documents Department

Experimental Investigation of Superradiance in a Tapered Free-Electron Laser Amplifier

Description: We report experimental studies of the effect of undulator tapering on superradiance in a single-pass high-gain free-electron laser (FEL) amplifier. The experiments were performed at the Source Development Laboratory (SDL) of National Synchrotron Light Source (NSLS). Efficiency was nearly tripled with tapering. Both the temporal and spectral properties of the superradiant FEL along the uniform and tapered undulator were experimentally characterized using frequency-resolved optical gating (FROG) images. Numerical studies predicted pulse broadening and spectral cleaning by undulator tapering Pulse broadening was experimentally verified. However, spectral cleanliness degraded with tapering. We have performed first experiments with a tapered undulator and a short seed laser pulse. Pulse broadening with tapering expected from simulations was experimentally confirmed. However, the experimentally obtained spectra degraded with tapering, whereas the simulations predicted improvement. A further numerical study is under way to resolve this issue.
Date: March 28, 2011
Creator: Hidaka, Y.; She, Y.; Murphy, J.B.; Podobedov, B.; Seletskiy, S. & Yang, X.
Partner: UNT Libraries Government Documents Department

THE FIRST LASING OF 193 NM SASE, 4TH HARMONIC HGHG AND ESASE AT THE NSLS SDL.

Description: The first lasing of three types of single-pass high-gain FELs, SASE at 193 nm, 4th harmonic HGHG at 199 nm and ESASE at the Source Development Lab (SDL) of Brookhaven National Laboratory (BNL) is reported. The saturation of 4th harmonic HGHG and ESASE FELs was observed. We also observed the spectral broadening and instability of the 4th harmonic HGHG.
Date: August 28, 2006
Creator: WANG, X.J.; Y., SHEN; WATANABE, T.; MURPHY, J.B.; ROSE, J. & TSANG, T.
Partner: UNT Libraries Government Documents Department

LONGITUDINAL DENSITY MODULATION OF UNSTABLE BUNCHES EMITTING COHERENT IR.

Description: Brookhaven National Laboratory's Accelerator Test Facility (ATF) has embarked on a complete upgrade of its decade old computer system. The planned improvements affect every major component: processors (Intel Pentium replaces VAXes), operating system (Linux/Real-Time Linux supplants OpenVMS), and data acquisition equipment (fast Ethernet equipment replaces CAMAC serial highway.) This paper summarizes the strategies and progress of the upgrade along with plans for future expansion.
Date: June 18, 2001
Creator: Podobedov, B.; Carr, G. L.; Kramer, S. L. & Murphy, J. B.
Partner: UNT Libraries Government Documents Department

Millimeter wave coherent synchrotron radiation in a compact electron storage ring

Description: Installation of a 2,856 MHz RF system into the XLS compact electron storage ring would allow the generation of millimeter wave coherent synchrotron radiation. Operating at 150 MeV, one could produce bunches containing on the order of 2 {times} 10{sup 7} electrons with a bunch length {sigma}{sub L0} = 0.3 mm, resulting in coherent emission at wavelengths above 0.8 mm. The characteristics of the source and the emitted radiation are discussed. In the case of 100 mrad horizontal collection angle, the average power radiated in the wavelength band 1 mm {le} {lambda} {le} 2 mm is 0.3 mW for single bunch operation and 24 mW for 80 bunch operation. The peak power in a single pulse of a few picosecond duration is on the order of one watt. By reducing the momentum compaction, the bunch length could be reduced to {sigma}{sub L0} = 0.15 mm, resulting in coherent synchrotron radiation down to 500 {micro}m.
Date: January 1, 1998
Creator: Murphy, J.B.; Blum, E.; Heese, R.; Keane, J. & Krinsky, S.
Partner: UNT Libraries Government Documents Department

Performance of the Phase 1 superconducting x-ray lithography source (SXLS) at BNL

Description: The Phase I SXLS electron storage ring has a circumference of 8.5 meters, it uses conventional dipole magnets, B {le} 1.1 T and p = 60 cm, and it is capable of operating in the range of 50--250 MeV. It is the forerunner of the Phase II SXLS ring which will operate at 700 MeV and will make use of superconducting dipoles, B{sub o} = 3.87 Tesla, as a source of {lambda}{sub c} = 10 angstrom x-rays for proximity printing lithography. The Phase I storage ring has been successfully commissioned; stored currents in excess of one ampere have been achieved. A report on the performance of the machine is presented.
Date: June 1, 1992
Creator: Murphy, J. B.; Biscardi, R.; Halama, H.; Heese, R.; Kramer, S.; Nawrocky, R. et al.
Partner: UNT Libraries Government Documents Department

Synchrotron radiation sources and condensers for projection x-ray lithography

Description: The design requirements for a compact electron storage ring that could be used as a soft x-ray source for projection lithography are discussed. The design concepts of the x-ray optics that are required to collect and condition the radiation in divergence, uniformity and direction to properly illuminate the mask and the particular x-ray projection camera used are discussed. Preliminary designs for an entire soft x-ray projection lithography system using an electron storage ring as a soft X-ray source are presented. It is shown that by combining the existing technology of storage rings with large collection angle condensers, a powerful and reliable source of 130{Angstrom} photons for production line projection x-ray lithography is possible.
Date: November 1, 1992
Creator: Murphy, J. B.; MacDowell, A. A.; White, D. L. & Wood, O. R. II
Partner: UNT Libraries Government Documents Department

FEL potential of eRHIC

Description: Brookhaven National Laboratory plans to build a 5-to-30 GeV energy-recovery linac (ERL) for its future electron-ion collider, eRHIC. In past few months, the Laboratory turned its attention to the potential of this unique machine for free electron lasers (FELS), which we initially assessed earlier. In this paper, we present our current vision of a possible FEL farm, and of narrow-band FEL-oscillators driven by this accelerator. eRHIC, the proposed electron-ion collider at BNL, takes advantage of the existing Relativistic Heavy Ion Collider (RHIC) complex. Plans call for adding a six-pass super-conducting (SRF) ERL to this complex to collide polarized- and unpolarized- electron beams with heavy ions (with energies up to 130 GeV per nucleon) and with polarized protons (with energies up to 325 GeV). RHIC, with a circumference of 3.834 km, has three-fold symmetry and six straight sections each {approx} 250 m long. Two of these straight sections will accommodate 703-MHz SRF linacs. The maximum energy of the electron beam in eRHIC will be reached in stages, from 5 GeV to 30 GeV, by increasing the lengths of its SRF linacs. We plan to install at the start the six-pass magnetic system with small gap magnets. The structure of the eRHIC's electron beam will be identical with that of its hadron beam, viz., 166 bunches will be filled, reserving about a one-microsecond gap for the abort kicker. With modest modifications, we can assure that eRHIC's ERL will become an excellent driver for continuous wave (CW) FELs (see Fig.1). The eRHIC's beam structure will support the operation of several such FELs in parasitic mode.
Date: August 23, 2010
Creator: Litvinenko, V.N.; Ben-Zvi, I.; Hao, Y.; Kao, C-C.; Kayran, D.; Murphy, J.B. et al.
Partner: UNT Libraries Government Documents Department

SOURCE OF MICROBUNCHING AT BNL NSLS SOURCE DEVELOPMENT LABORATORY

Description: We report experimental studies of the origins of electron beam microbunching instability at BNL Source Development Laboratory (SDL). We eliminated laser-induced microbunching by utilizing an ultra-short photocathode laser. The measurements of the resulting electron beam led us to conclude that, at SDL, microbunching arising from shot noise is not amplified to any significant level. Our results demonstrated that the only source of microbunching instability at SDL is the longitudinal modulation of the photocathode laser pulse. Our work shows that assuring a longitudinally smoothed photocathode laser pulse allows mitigating microbunching instability at a typical FEL injector with a moderate microbunching gain. In this paper we investigated the source of microbunching instability at the SDL. To distinguish microbunching induced by shot noise from that arising from the longitudinal modulation of the photocathode laser, we studied the beam created by a very short laser pulse, thus eliminating the possibility of laser-induced microbunching. While the measured energy spectra of compressed beam did reveal severe longitudinal fragmentation, an analysis of the beam dynamics proved this to be due to self-fields acting on a beam with an initially smooth longitudinal profile, and not due to microbunching instability. Such fragmentation only was possible with the very short bunch chosen for these studies, and is absent in routine SDL operations. Our experiment shows that in the absence of the initial laser-induced beam modulation, microbunching instability at the SDL is not observed, and must be well below the levels that would limit the FEL performance. This result agrees with assumption of previous SDL studies that (when present under different machine conditions) microbunching instability at the SDL was laser-induced. Microbunching instability gain at the SDL is moderate. This is mainly because the SDL utilizes a single stage bunch compressor as well as due to the small compression ratio. Since the ...
Date: March 28, 2011
Creator: Seletskiy, S.; Hidaka, Y.; Murphy, J.B.; Podobedov, B.; Qian, H.; Shen, Y. et al.
Partner: UNT Libraries Government Documents Department

High Brightness Electron Beam Studies at the NSLS SDL

Description: Experimental optimization of electron beam brightness at the NSLS SDL is reported in this paper. Using a high quantum efficiency (QE) Mg metal cathode and the S-band BNL-type RF gun, we have systematically studied electron beams transverse and longitudinal emittance. The measured thermal emittance for the Mg cathode is 0.85{+-}0.04 mm-mrad/mm, which contradicts the current thermal emittance model. For a 50 pC beam, measured normalized transverse and longitudinal RMS emittance are 0.6 mm-mrd and 5.2 ps-keV, respectively. The smallest projected transverse emittance observed for a 20 pC charge is 0.15 {+-} 0.02 mm-mrad.
Date: May 4, 2009
Creator: Qian,H.; Hidaka, Y.; Murphy, J. B.; Podobedov, B.; Seletskiy, S.; Shen, Y. et al.
Partner: UNT Libraries Government Documents Department

Interplay of the Chirps and Chirped Pulse Compression in a High-gain Seeded Free-electron Laser

Description: In a seeded high-gain Free-electron Laser (FEL), where a coherent laser pulse interacts with an ultra-relativistic electron beam, the seed laser pulse can be frequency chirped, and the electron beam can be energy chirped. Besides these two chirps, the FEL interaction introduces an intrinsic frequency chirp in the FEL even if the above mentioned two chirps are absent. In this paper we examine the interplay of these three chirps. The problem is formulated as an initial value problem, and solved via a Green function approach. Besides the chirp evolution, we also give analytical expressions for the pulse duration and bandwidth of the FEL, which remains fully longitudinally coherent in the high gain exponential growth regime. Because the chirps are normally introduced for a final compression of the FEL pulse, some conceptual issues are discussed. We show that in order to get a short pulse duration, an energy chirp in the electron beam is necessary.
Date: January 3, 2007
Creator: Wu, Juhao; /SLAC; Murphy, J.B.; /LBNL, ALS; Emma, P.J.; /SLAC et al.
Partner: UNT Libraries Government Documents Department

Timing Jitter Characterization at the NSLS SDL

Description: Two novel timing jitter measurement techniques with a 100 fs resolution are presented in this paper. The first technique based on the Schottky effect, is used to measure the timing jitter between the photoinjector drive laser and the RF system; and it was employed to characterize the environment effects on the timing jitter. The I/Q beam monitor based on a stripline beam position monitor (BPM) is used to characterize the electron beam arrival time jitter.
Date: May 4, 2009
Creator: Qian,H.; Hidaka, Y.; Murphy, J. B.; Podobedov, B.; Seletskiy, Shen, Y.; Yang, X. et al.
Partner: UNT Libraries Government Documents Department