John Vetrovec

Operating experience with a high-throughput jet generator

Over the last several years, Rocketdyne has conducted a number of experiments on advanced jet generators. Both cross flow jet generator and counter flow jet generators have been tested. We have made laser power measurements at our Continuous Wave Chemical Laser Facility (CWLL) and at the Air Force Phillips Laboratory RADICL test facility. A test there resulted in a measured chemical efficiency of 29.6%. This is the highest efficiency reported for a supersonic oxygen-iodine chemical laser.

Chemical oxygen-iodine laser with cryosorption vacuum pump

In a chemical oxygen-iodine laser (COIL), chemically prepared, gaseous gain medium at 3-10 Torr pressure is drawn through the laser cavity by vacuum suction. Multiple-stage vacuum pumps such as Roots blowers or steam ejectors are typically used to receive and compress the gas flowing from the laser and exhaust it to the atmosphere. The size and weight of such vacuum pumps present a significant challenge to engineering and packaging a transportable COIL system.

Singlet oxygen generator with filament-guided jets

This work describes a new version of a jet singlet oxygen generator using filaments to guide basic hydrogen peroxide jets. The resulting jets are highly stable and resistant to aerodynamic forces.

Electrochemical production of basic hydrogen peroxide and chlorine for use in chemical oxygen-iodine laser

This work describes a configuration of an electrochemical apparatus for production chlorine and basic hydrogen peroxide and discusses its use in a continuously operating COIL system consuming only electric power and air.

Conceptual design of an industrial chemical oxygen-iodine laser

This work describes a conceptual design of an industrial chemical oxygen-iodine laser and its applications to dismantlement of nuclear reactors and to aluminum cutting and welding. Choices of specific technologies and system components are made with the aid of a system cost model.

Chemical oxygen-iodine laser (COIL) for the dismantlement of nuclear facilities

The dismantlement of obsolete nuclear facilities is a major challenge for both the US Department of Energy and nuclear power utilities. Recent demonstrations have shown that lasers can be highly effective for size reduction cutting, especially for the efficient storage and recycling of materials. However, the full benefits of lasers can only be realized with high average power beams that can be conveniently delivered, via fiber optics, to remote and/or confined areas. Industrial lasers that can meet these requirements are not available now or for the foreseeable future. However, a military weapon laser, a Chemical Oxygen Iodine Laser (COIL), which has been demonstrated at over a hundred kilo Watts, could be adapted to meet these needs and enable entirely new industrial applications. An industrialized COIL would enable rapid sectioning of thick and complex structures, such as glove boxes, reactor vessels, and steam generators, accelerating dismantlement schedules and reducing worker hazards. The full advantages of lasers in dismantlement could finally be realized with a portable COIL which is integrated with sophisticated robotics. It could be built and deployed in less than two years, breaking the paradigm of labor-intensive dismantlement operations and cutting processing times and costs dramatically.

Analysis and testing of rod-like penetrators in the 4-5 km/s velocity regime

This work describes the analysis and ballistic range testing to evaluate the performance of rod-like Kill Enhancement Device (KED) penetrators on of multi-layered targets covering large range of densities including high-density material. Tests showed that (1) high-density material can be penetrated at oblique angles of incidence without projectile fragmentation and (2) high explosive within the target can be initiated. Test data from experiments was compared to predictive analyses generated by hydrocodes and found to be in excellent agreement.

Use of basic deuterium peroxide in the chemical oxygen-iodine laser

The chemical oxygen-iodine laser (COIL) uses a reaction of gaseous chorine and aqueous solution of basic oxygen peroxide (BHP) to produce oxygen singlet delta molecules, O2(1(Delta) ). Quenching of O2(1(Delta) ) during its extraction from the BHP solution and quenching of excited atomic iodine I* by water vapor from the O2(1(Delta) ) production process are well-known parasitic effects in COIL. This paper shows that both of these effects can be significantly reduced by replacing the hydrogen 1H1 isotope atoms in BHP by the 1H2 isotope atoms. In addition to restoring laser power lost to parasitic quenching, use of basic deuterium peroxide (BDP) rather than BHP is expected to allow generation of O2(1(Delta) ) at elevated temperature. This approach promises to save refrigerant, reduce the risk of BDP freezing, and delay precipitation of salt form BDP solution. Methods for producing BDP are outlined.

Regeneration of basic hydrogen peroxide and chlorine for use in chemical oxygen iodine laser

The chemical oxygen-iodine laser derives its energy from the reaction of basic hydrogen peroxide with chlorine. The traditional oxygen-iodine laser uses an open loop cycle, in which fresh reactants are furnished in bulk form. This approach is not suitable for a continuously operating laser because supplying fresh reactants and disposing of reaction products are expensive and require significant logistics. This work describes a new concept for continuous in-situ regeneration of chlorine and basic hydrogen peroxide.

Lasing performance of an edge-pumped ceramic Yb:YAG disk laser with a tailored spatial gain profile (Conference Presentation)

We report on testing of an edge-pumped ceramic Yb:YAG disk laser having a tailored spatial gain profile for preferential amplification of the TEM00 mode. The disk has a composite construction with a Yb-doped large-aperture central portion cosintered with an undoped perimetral edge. Light from multi-kW diodes is transported though the disk edge and absorbed in the Yb-doped center. This configuration makes it poss¬ible to conveniently arrange the diode light and produce a spatially flat gain profile, such as is desir¬able for the amplification of a spatial flat top beam or a tailored gain profile [1]. Amplified spontan¬eous emis¬sion (ASE) and parasitic lasing is mitigated by the geometry of the laser disk edge, which is designed to efficiently outcouple laser fluorescence [2]. nThis work experimentally investigated the tailored spatial gain profile and the lasing performance of TEM00 mode (Gaussian spatial profile) beam without the distorting effects of gain saturation. Compari¬son of the lasing performance of a flat spatial gain to that with tailored gain is presented. This work was supported in-part by the US Department of Energy grants DE-SC0013762 and DE-SC0015834. nn1. Drew A. Copeland and John Vetrovec, “Gain Tailoring Model and Improved Optical Extraction nin CW Edge–Pumped Disk Amplifiers,” SPIE Vol. 8235, 82350U (2012).n2. John Vetrovec, Drew A. Copeland, Amardeep S. Litt, Suraj J. Thiagarajan, and Eldridge Briscoe Stored Energy and Gain in an Edge-Pumped Ceramic Yb:YAG Disk Laser under Intense Pumping, SPIE Vol. 10084, 1008407 (2017).