B.N. Turman

Results from Sandia National Laboratories / Lockheed Martin Electromagnetic Missile Launcher (EMML)

Sandia national laboratories (SNL) and lockheed martin MS2 are designing an electromagnetic missile launcher (EMML) for naval applications. Lhe EMML uses an induction coilgun topology with the requirement of launching a 3600 lb. missile up to a velocity of 40 m/s. Lo demonstrate the feasibility of the electromagnetic propulsion design, a demonstrator launcher was built that consists of approximately 10% of the propulsion coils needed for a tactical design. Lhe demonstrator verified the design by launching a 1430 lb weighted sled to a height of 24 ft in mid-December 2004 (Figure 1). Lhis paper provides the general launcher design, specific pulsed power system component details, system operation, and demonstration results.

Coilgun technology, status, applications and future directions at Sandia National Laboratories

Sandia National Laboratories has been developing coilgun electromagnetic launcher technology since 1980 and is continuing to advance the technology through hardware development, industry collaboration, and pursuit of new applications. Past projects have included a 35 stage, 200 kJ, 50 mm launcher accelerating a 0.23 kg mass to 1 km/s velocity, a 6 stage, 280 kJ, 140 mm system accelerating a 5 kg mass to 335 m/s, and several studies documenting the potential capabilities of coilgun technology for low and high-speed applications. Projects are currently underway that will continue to advance the technology. One such program is testing high field coils to determine if previous designs can withstand the stress of large numbers of shots. This project is also developing a 30 Tesla coil to allow operation at repetition rates necessary for many applications. At the conclusion of this project we will have valuable engineering data on long-term coil reliability for high velocity applications. We are also working with an industry partner to develop a low-velocity, high-mass electromagnetic launcher for missile launch applications. Through a cooperative research and development agreement, we have constructed a small-scale model, conducted full-scale conceptual designs, and are proceeding to construct a facility for testing full-scale coils and EM effects on missile components. We are developing a coilgun launcher for DoD mortar applications that require launch velocities of -400 m/s of 120 mm, 18 kg payloads, and will extend the weapons range 40% beyond existing technology while providing significantly improved accuracy with slight modification to the existing rounds. For the mortar application, the program is designed to build both rail and coil systems to identify the strengths and weaknesses of each, and which is most appropriate for the DoD requirements

Study of coilgun performance and comments on powered armatures

Electromagnetic launch technology is being developed at Sandia National Laboratories (SNL) for applications such as high-speed transit, military defense, and space vehicle launching. A lumped-parameter circuit simulation code called Slingshot was developed by SNL to simulate launcher performance (B.M. Marder, 2001). This software calculates self and position-dependent mutual inductances, and temperature-dependent resistances to determine the electrical circuit response self-consistently with the equations of motion for the projectile. The software was designed to simulate high velocity projectile applications where an inductively driven armature was desirable. The armature is modeled as series RL circuit to represent a conductive single-turn loop or a coil winding and did not include any sources. However under some circumstances, such as lower velocity designs for missile launchers, a powered projectile may have some advantages. Such coils could be powered by a small onboard capacitor bank, batteries, or through an external supply. This paper will discuss the operation and some of the design parameters for a general coil gun as well as the circumstances under which a powered armature is desirable

An overview of electron beam decontamination technology and applications

High-energy radiation is an effective means of decontamination, including sterilization, sanitization, and pasteurization. The principal sources are radioisotope and machine-generated radiation. Radioisotope sources use radioactive materials such as /sup 60/Co or /sup 137/Cs, which produce gamma radiation from nuclear decay. The inventory of radioactive material is typically 1 MegaCurie or more for a high-volume radioisotope irradiator. In contrast, the machine-generated radiation is obtained from an electrical power source that first produces a high-energy electron beam, to be used in a direct e-beam mode or in an indirect X-ray mode. The advantages of the machine-generated radiation are related to the lack of radioactive materials inventory, the ability to configure the radiation output to optimize coupling into the product, the reliability of modern industrial accelerators, and the relative simplicity of engineering the accelerator to the irradiator facility. The choice between the direct electron beam and indirect X-ray conversion systems is typically made as a trade-off between efficiency and product penetration distance. The efficiency of X-ray conversion of electron energy to total radiation is about 18 percent at 10 MeV. The major advantage of the X-ray process is the longer penetration distance, a factor of about 5 greater than that for the direct electron beam for typical treatment conditions. Accelerator technology and irradiation applications will be discussed, including food pasteurization, medical sterilization, and other decontamination applications. Several examples will be used to illustrate design choices and practical tradeoffs for these applications.

Effects of thermoradiation treatments on the DNA of bacillus subtilis endospores

Endospores of the bacterium, Bacillus subtilis, have been shown to exhibit a synergistic rate of cell death when treated with particular levels of heat and ionizing radiation in combination. However, the mechanism of the synergistic action is unknown. This study attempted to determine whether the mechanism of synergism was specifically connected to the DNA strand breakage-either single strand breakage or double strand breakage. Bacillus subtilis spores were treated at combinations of 33 kr/hr, 15 kr/hr, 105/spl deg/C, 85/spl deg/C, 63/spl deg/C, and 50/spl deg/C. Some synergistic correlation was found with the number of double strand breaks, and a strong correlation was found with the number of single strand breaks. In cases displaying synergism of spore killing, single strand breakage while the DNA was in a denatured state is suspected as a likely mechanism.

Recent progress in cryogenic techniques applied to pulsed ion beam generation and target ablation experiments

The authors are still continuing their efforts to apply cryogenic techniques to pulsed ion beam generation and target ablation experiments with such ion beams. In this article, the most recent progress and the most interesting results in this field are described. One of their experiments is to produce pulsed ion beams with a cryogenic anode diode. They used N/sub 2/O ice as the ion source to get medium mass ion beams. The anode was cooled with a cryogenic cooler. A pulsed power machine (PICA-3) at Yokohama was used to produce ion beams. The diode characteristics were measured together with the ion beam characteristics. A biased ion collector, the Thomson parabola track detector, was used to measure the time of flight of the beams and the beam energy and species. The beam divergence angle was estimated with a multi-pinhole camera with the time integrated track detector. This divergence angle was compared with the case of the light ion beams, and the future direction was discussed for the development of the medium mass pulsed ion beams as one of the ICF beam candidates. Their other experiment irradiated cryogenic targets with pulsed ion beams.

High voltage high brightness electron accelerators with MITL voltage adder coupled to foilless diodes

Summary form only given. It has recently been experimetnally and theoretically demonstrated that foilless diodes can be successfully coupled to self-magnetically insulated transmission line voltage adders to produce very small high-brightness, high-definition (no halo) electron beams. The RADLAC/SMILE experience opened the path to a new approach in high-brightness, high-energy induction accelerators. There is no beam drifting through the device. The voltage addition occurs in a center conductor, and the beam is created at the high voltage end in an applied magnetic field diode. This work was motivated by the remarkable success of the HERMES-III accelerator and the need to produce small-radius, high-energy, high-current electron beams for air propagation studies and flash X-ray radiography. Design examples of devices that can produce multikiloamp electron beams of as high as 100 MV energies and with radii as small as 1 mm have been considered.