• JLA Vol:8 Iss:2 (Obtaining laser safety at a synchrotron radiation user facility: The Advanced Light Source)


    Authors:
    Kenneth Barat
    Lawrence Berkeley National Laboratory, MS 90‐2148, 1 Cyclotron Road, Berkeley, CA 94720, U.S.A.


    The Advanced Light Source (ALS) is a United States national facility for scientific research and development located at the Lawrence Berkeley National Laboratory in California. The ALS delivers the world's brightest synchrotron radiation in the far ultraviolet and soft X‐ray regions of the spectrum. As a ‘user facility’ it is available to researchers from industry, academia, and laboratories from around the world. Subsequently, a wide range of safety concerns become involved. This article relates not only to synchrotron facilities but to any ...

    $25.00

  • JLA Vol:8 Iss:2 (Recent progress in laser surface treatment: <emph type="4">II</emph>. Adopted processing for high efficiency and quality)


    Authors:
    W. Bloehs
    B. Gru¨nenwald
    F. Dausinger
    H. Hu¨gel
    Institut fu¨r Strahlwerkzeuge, Universita¨t Stuttgart, Pfaffenwaldring 43, 70569 Stuttgart, Germany


    In Part I of this contribution, energy coupling and transport mechanisms were considered in detail. The second part concentrates on the effect of the spatial distribution of the energy in the laser beam, which will be discussed in connection with applications of laser surface technologies. Along these lines, a variety of beam shaping facilities is presented for laser hardening and cladding. Their purpose is to adapt the irradiated area to the workpiece ge...

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  • JLA Vol:8 Iss:2 (Trepan drilling of fuel injection nozzles with a TEM<sub>00</sub> Nd:YAG slab laser)


    Authors:
    H. Rohde
    E. Meiners



    Holes of 160 μm diameter were trepan drilled in fuel injection nozzles of 1 mm thickness by means of a TEM00 fundamental mode Nd:YAG slab laser. Two different types of holes have been trepan drilled: at an angle of 90°, and at an angle of 60° to the metal surface. The influence of nozzle distance, focal position, gas pressure, pulse repetition frequency and trepanning velocity on the hole diameter and on the conicity are investigated. A diameter accuracy of ±10 μm and a conicity of 3&percnt; were achieved. One hole is drilled in 7–25 seconds in dependence of the drilling strategy.

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  • JLA Vol:8 Iss:3 (A study of laser&hyphen;based removal of polymethylmethacrylate bone cement)


    Authors:
    W. O'Neill
    P. Kapadia
    T. Thomas



    Complications are often produced with the removal of bone cement from the femoral cavity in the treatment of a failed hip prosthesis. Apart from being slow and difficult the conventional process runs the risk of producing damage to the femur. Ultrasonic techniques have been suggested to achieve these ends but removal of the cement by this approach is not entirely easy. The alternative laser&hyphen;based approach would seem to have significant advantages over conventional techniques. The laser is capable of delivering energy to a specific region or surface under close control. The choice of laser is determined by its a...

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  • JLA Vol:8 Iss:3 (Commonwealth of Independent States (CIS) laser scene and Laser Association (LAS) activities)


    Authors:
    Ivan B. Kovsh
    LAS Headquarters, Moscow, Rozhdestvenkastr, 27, 117485, Russia


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  • JLA Vol:8 Iss:3 (High&hyphen;power, high&hyphen;beam&hyphen;quality solid&hyphen;state lasers for materials processing applications)


    Authors:
    Lloyd A. Hackel
    C. Brent Dane
    Mark R. Hermann
    John Honig
    Luis E. Zapata
    Mary A. Norton
    Lawrence Livermore National Laboratory, P.O. Box 808, L&hyphen;487, Livermore, CA 94550, U.S.A.


    The Laser Science and Technology Department at Lawrence Livermore National Laboratory is developing solid&hyphen;state lasers with high average power and high beam quality. Specific systems include a laser to generate 1.0–1.4 nm X&hyphen;rays for proximity print lithography, a 400&hyphen;mJ, 500&hyphen;Hz laser for 13.0 nm projection lithography and unique systems for speckle imaging, laser radars, and medical treatments.

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  • JLA Vol:8 Iss:3 (Laser Hardened Materials Evaluation Laboratory (LHMEL))


    Authors:
    R. J. Hull
    M. L. Lander



    Since 1976, the Laser Hardened Materials Evaluation Laboratory (LHMEL) has been characterizing material responses to laser energy in support of national defense programs and the aerospace industry. Now that capability is available to commercial industry as well. LHMEL's power levels, beam uniformity, and diagnostics capabilities make it an ideal facility for proof&hyphen;of&hyphen;concept testing or process development. Located at Wright&hyphen;Patterson Air Force Base, Ohio, LHMEL is managed by the Wright Laboratory Materials Directorate and operated by Lawrence Associates, Incorporated. The facility's advanced hardware is centered aroun...

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  • JLA Vol:8 Iss:3 (Laser shock processing of materials, physical processes involved and examples of applications)


    Authors:
    P. Peyre
    R. Fabbro
    L. Berthe
    C. Dubouchet



    Laser shock processing (LSP) consists of irradiating a metallic target with a short (about 20 ns) and intense (>1013W m−2) laser light in order to generate, through a high pressure surface plasma (>1 GPa), a plastic deformation and a surface strengthening within materials. This paper initially reviews the physical processes involved in the analytical modeling of the generation pressure mechanism in a confined plasma regime. Limiting factors such as the dielectric breakdown in the confining medium are also discussed together with current research directions aimed...

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  • JLA Vol:8 Iss:3 (Parametric studies of cutting zircaloy&hyphen;2 sheets with a laser beam)


    Authors:
    Swati Ghosh
    B. P. Badgujar
    G. L. Goswami
    Atomic Fuels Division, Bhabha Atomic Research Centre, Trombay, Bombay &hyphen; 400 085, India


    The highly reactive and pyrophoric nature of zirconium alloys limits the use of conventional thermal sources (e.g., plasma arc cutting, oxygen flame cutting, etc.) for the cutting and drilling of these alloys. In this context, a highly coherent laser beam provides a good alternative for the cutting and drilling. In the present paper, laser beam cutting of zircaloy&hyphen;2 sheets of 1.1 mm and 0.74 mm thickness is performed using a 300 W average power pulsed Nd:YAG laser. Pulse energy, pulse repetition rate, nozzle ga...

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  • JLA Vol:8 Iss:3 (Theoretical and experimental studies of thick&hyphen;section cutting with a chemical oxygen&ndash;iodine laser (COIL))


    Authors:
    A. Kar
    J. E. Scott
    W. P. Latham



    A simple mathematical model of thick&hyphen;section stainless steel cutting with a high power chemical oxygen–iodine laser (COIL) is presented and compared with experimental results obtained with a 10&hyphen;kilowatt COIL at the U.S. Air Force's Phillips Laboratory. This model uses a lumped&hyphen;parameter technique to relate the cutting kerf depth with various process parameters and can be used to predict scaled laser materials processing performance to very thick sections. The model is similar to an empirical model developed by researchers in Japan, but includes predictive capabilities for thick metal cutting...

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