Joseph Menapace - Profile on Academia.edu (original) (raw)

Papers by Joseph Menapace

Corrective optical elements form an important part of high‐precision optical systems. We have dev... more Corrective optical elements form an important part of high‐precision optical systems. We have developed a method to manufacture high‐gradient corrective optical elements for high‐power laser systems using deterministic MRF imprinting technology. Several process factors need to be considered for polishing ultra‐precise topographical structures onto optical surfaces using MRF. They include proper selection of MRF removal function and wheel sizes, detailed MRF tool and interferometry alignment, and optimized MRF polishing schedules. Dependable interferometry is also a key factor to high‐gradient component manufacture. A wavefront attenuating cell is discussed that enables reliable measurement of gradients beyond that attainable using conventional interferometry. The results of MRF imprinting a 23‐m deep structure containing gradients over 1.6 m/mm onto a fused silica window are presented as an example of the technique's capabilities. This high‐gradient element serves as a thermal correction plate in the High‐Repetition‐Rate Advanced Petawatt Laser System (HAPLS) currently being built at Lawrence Livermore National Laboratory. OCIS codes: (140.0140) Lasers and laser optics; (140.3300) Laser beam shaping; (220.0220) Optical design and fabrication; (220.1000)

Developing magnetorheological finishing (MRF) technology for the manufacture of large-aperture optics in megajoule class laser systems

Laser-Induced Damage in Optical Materials: 2010, 2010

ABSTRACT Over the last eight years we have been developing advanced MRF tools and techniques to m... more ABSTRACT Over the last eight years we have been developing advanced MRF tools and techniques to manufacture meter-scale optics for use in Megajoule class laser systems. These systems call for optics having unique characteristics that can complicate their fabrication using conventional polishing methods. First, exposure to the high-power nanosecond and sub-nanosecond pulsed laser environment in the infrared (>27 J/cm2 at 1053 nm), visible (>18 J/cm2 at 527 nm), and ultraviolet (>10 J/cm2 at 351 nm) demands ultra-precise control of optical figure and finish to avoid intensity modulation and scatter that can result in damage to the optics chain or system hardware. Second, the optics must be super-polished and virtually free of surface and subsurface flaws that can limit optic lifetime through laser-induced damage initiation and growth at the flaw sites, particularly at 351 nm. Lastly, ultra-precise optics for beam conditioning are required to control laser beam quality. These optics contain customized surface topographical structures that cannot be made using traditional fabrication processes. In this review, we will present the development and implementation of large-aperture MRF tools and techniques specifically designed to meet the demanding optical performance challenges required in large aperture high-power laser systems. In particular, we will discuss the advances made by using MRF technology to expose and remove surface and subsurface flaws in optics during final polishing to yield optics with improve laser damage resistance, the novel application of MRF deterministic polishing to imprint complex topographical information and wavefront correction patterns onto optical surfaces, and our efforts to advance the technology to manufacture largeaperture damage resistant optics.

EPRFIT: An electron paramagnetic resonance modeling and analysis package Version 1. 10. Technical report

Unknown, Dec 1, 1991

EPRFIT is a computerized analysis and modeling package which simulates isotropic EPR spectra. The... more EPRFIT is a computerized analysis and modeling package which simulates isotropic EPR spectra. The package performs first and second order spectral simulations of both single configuration species and exchange-broadened species containing up to 7 exchanging configurations. The program simulates spectra composed of up to 2200 individual lines and up to 14 distinct spin species with nuclear spins within the range 0-9.5. The various procedures within the program are accessed via a user friendly menu-based package. Data entry is conducted using a spreadsheet architecture which provides the user with easy access to data for inspection and editing. Simulation data, simulated spectra, and experimental/simulated spectrum comparison files can be retrieved and stored onto hard/floppy disk storage in either ASCII or packed formats. ASCII output provides a useful means for linking the data/spectra to other analysis packages as well as for use in printing/plotting routines. The simulated and comparison spectra can also be displayed and analyzed graphically within the program. Spectral analysis options include spectrum offsetting, panning, zooming, and peak position and intensity identification routines. These operations apply to both simulated and comparison spectra. Hardcopies of the simulation results and any combination of spectra can be printed onto Epson compatible dot matrix printers for future reference or presentation.

Method and System for Processing Optical Elements Using Magnetorheological Finishing

This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-ind... more This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-induced surface damage sites on large-aperture fused silica optics. We will show the effect of various 355-nm laser conditioning methodologies on the reduction of surface-damage initiation in fused silica samples that have varying qualities of polishing. With the best, generally available fused silica optic, we have demonstrated that 355-nm laser conditioning can achieve up to 10x reduction in surface damage initiation concentration in the fluence range of 10-14 J/cm 2 (355-nm @ 3 ns).

Van der Waals clusters of aromatic molecules studied using supersonic molecular jet spectroscopy

ABSTRACT

Laser-Induced Damage in Optical Materials: 2003, 2004

Magnetorheological finishing (MRF) techniques have been developed to manufacture continuous phase... more Magnetorheological finishing (MRF) techniques have been developed to manufacture continuous phase plates (CPP's) and custom phase corrective structures on polished fused silica surfaces. These phase structures are important for laser applications requiring precise manipulation and control of beam-shape, energy distribution, and wavefront profile. The MRF's unique deterministic-sub-aperture polishing characteristics make it possible to imprint complex topographical information onto optical surfaces at spatial scale-lengths approaching 1 mm. In this study, we present the results of experiments and model calculations that explore imprinting two-dimensional sinusoidal structures. Results show how the MRF removal function impacts and limits imprint fidelity and what must be done to arrive at a high quality surface. We also present several examples of this imprinting technology for fabrication of phase correction plates and CPPs for use at high fluences.

Large-aperture diffractive optical elements for high power laser and space applications

Frontiers in Optics 2004/Laser Science XXII/Diffractive Optics and Micro-Optics/Optical Fabrication and Testing, 2004

Laser-Induced Damage in Optical Materials: 2005, 2005

ABSTRACT Antireflection (AR) coatings typically damage at the interface between the substrate and... more ABSTRACT Antireflection (AR) coatings typically damage at the interface between the substrate and coating. Therefore the substrate finishing technology can have an impact on the laser resistance of the coating. For this study, AR coatings were deposited on Yb:S-FAP [Yb3+:Sr5(PO4)3F] crystals that received a final polish by both conventional pitch lap finishing as well as magnetorheological finishing (MRF). SEM images of the damage morphology reveals laser damage originates at scratches and at substrate coating interfacial absorbing defects. Previous damage stability tests on multilayer mirror coatings and bare surfaces revealed damage growth can occur at fluences below the initiation fluence. The results from this study suggest the opposite trend for AR coatings. Investigation of unstable HR and uncoated surface damage morphologies reveals significant radial cracking that is not apparent with AR damage due to AR delamination from the coated surface with few apparent cracks at the damage boundary. Damage stability tests show that coated Yb:S-FAP crystals can operate at 1057 nm at fluences around 20 J/cm2 at 10 ns; almost twice the initiation damage threshold.

Laser Beam Shaping IX, 2008

Laser-Induced Damage in Optical Materials: 2001, 2002

This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-ind... more This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-induced surface damage sites on large-aperture fused silica optics. We will show the effect of various 355-nm laser conditioning methodologies on the reduction of surface-damage initiation in fused silica samples that have varying qualities of polishing. With the best, generally available fused silica optic, we have demonstrated that 355-nm laser conditioning can achieve up to 10x reduction in surface damage initiation concentration in the fluence range of 10-14 J/cm 2 (355-nm @ 3 ns).

Chemiluminescent Reaction of Tellurium with Fluorine

Laser-Induced Damage in Optical Materials: 2006, 2006

The Mercury laser uses ytterbium-doped strontium fluorapatite (Yb:S-FAP) crystals as the gain med... more The Mercury laser uses ytterbium-doped strontium fluorapatite (Yb:S-FAP) crystals as the gain medium with a nominal clear aperture of 4 x 6 cm. Recent damage test data have indicated the existence of bulk precursors in Yb:S-FAP that initiate damage starting at approximately 10 J/cm2 at 9 ns under 1064 nm irradiation. In this paper, we report on preliminary results on

Solid State Lasers XIII: Technology and Devices, 2004

We report initial operation of the Mercury laser with seven 4 x 6 cm S-FAP amplifier slabs pumped... more We report initial operation of the Mercury laser with seven 4 x 6 cm S-FAP amplifier slabs pumped by four 80 kW diode arrays. The system produced up to 33.5 J single shot, 23.5 J at 5 Hz, and 10 J at 10 Hz for 20 minute runs at 1047 nm. During the initial campaign, more than 2.8 x 104

Van der Waals modes of solute/solvent clusters: benzene-methane, -deuteriomethane, and -carbon tetrafluoride

The Journal of Physical Chemistry, 1987

ABSTRACT

Photochemical and thermochemical decomposition of 3-nitro-1,2,4-triazol-5-one and perdeuterio-3-nitro- 1,2,4-triazol-5-one in neat and mixed systems. (Reannouncement with new availability information)

The Journal of Physical Chemistry, 1991

... Chem. 1985.89,4809. (f) Shackelford. S. A.; Goshgarian, BB; Chapman, RD; Askins, RE; Flanigan... more ... Chem. 1985.89,4809. (f) Shackelford. S. A.; Goshgarian, BB; Chapman, RD; Askins, RE; Flanigan, DA; Rogers, RN Propellants, Explos. Pyrotech. 1989,14,93. ... Shackelford, SA J. Phys. (Paris) 1987, 48, C4-193. (7) (a) Menapace, JA; Marlin, JE J . Phys. Chem. 1990,94,1906. ...

Public reporting burden for this collection of information is estimated to average 1 hour per res... more Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. , and partially deuterium-labeled DNNC-d 2 and DNNC-d 4 isotopomers were obtained by isothermal differential scanning calorimetry (IDSC). Molecular kinetic deuterium isotope effect (KDIE) values obtained with DNNC and DNNC-d 6 from 174 to 194 o C revealed that C-H bond rupture regulates both an endothermic catalytic initiation and the exothermic propagation of the liquid thermochemical decomposition process. Using IDSC-based KDIE comparisons with the DNNC-d 2 , DNNC-d 4 , and DNNC-d 6 isotopomers, a more detailed chemical structure/mechanistic relationship emerged by entering the interior of the DNNC molecule. Here structural kinetic KDIE results showed the rate-controlling C-H bond rupture has its origin at the non-equivalent C-2 methylene group sandwiched between the two nitrated DNNC nitrogen ring atoms, versus at the chemically equivalent C-4 and C-6 methylene ring positions located elsewhere in the DNNC molecule. Elucidation of such mechanistic features should aid in the structural design of new high energy compounds with improved thermochemical properties. A 170.0 kJ/mol activation energy appeared for the endothermic induction period, and a lower 104.2 kJ/mol activation energy was determined for the exothermic acceleratory portion of the DNNC decomposition process. The global liquid and solid state thermochemical decomposition processes for DNNC are compared. a. REPORT b. ABSTRACT c. THIS PAGE 19b. TELEPHONE NUMBER (include area code) SAR 62 N/A Unclassified Unclassified Unclassified Standard Form 298 (Rev. 8-98) __________________________________________________________________________ Abstract Global kinetics for the liquid state thermochemical decomposition of neat 1,3,5,5tetranitrohexahydropyrimidine (DNNC), perdeuterio-labeled DNNC-d 6 , and partially deuterium-labeled DNNC-d 2 and DNNC-d 4 isotopomers were obtained by isothermal differential scanning calorimetry (IDSC). Molecular kinetic deuterium isotope effect (KDIE) values obtained with DNNC and DNNC-d 6 from 174 to 194 o C revealed that C-H bond rupture regulates both an endothermic catalytic initiation and the exothermic propagation of the liquid thermochemical decomposition process. Using IDSC-based KDIE comparisons with the DNNC-d 2 , DNNC-d 4 , and DNNC-d 6 isotopomers, a more detailed chemical structure/mechanistic relationship emerged by entering the interior of the DNNC molecule. Here structural kinetic KDIE results showed the rate-controlling C-H bond rupture has its origin at the non-equivalent C-2 methylene group sandwiched between the two nitrated DNNC nitrogen ring atoms, versus at the chemically equivalent C-4 and C-6 methylene ring positions located elsewhere in the DNNC molecule. Elucidation of such mechanistic features should aid in the structural design of new high energy compounds with improved thermochemical properties. A 170.0 kJ/mol activation energy appeared for the endothermic induction period, and a lower 104.2 kJ/mol activation energy was determined for the exothermic acceleratory portion of the DNNC decomposition process. The global liquid and solid state thermochemical decomposition processes for DNNC are compared.

Combined advanced finishing and UV laser conditioning process for producing damage resistant optics

Corrective optical elements form an important part of high‐precision optical systems. We have dev... more Corrective optical elements form an important part of high‐precision optical systems. We have developed a method to manufacture high‐gradient corrective optical elements for high‐power laser systems using deterministic MRF imprinting technology. Several process factors need to be considered for polishing ultra‐precise topographical structures onto optical surfaces using MRF. They include proper selection of MRF removal function and wheel sizes, detailed MRF tool and interferometry alignment, and optimized MRF polishing schedules. Dependable interferometry is also a key factor to high‐gradient component manufacture. A wavefront attenuating cell is discussed that enables reliable measurement of gradients beyond that attainable using conventional interferometry. The results of MRF imprinting a 23‐m deep structure containing gradients over 1.6 m/mm onto a fused silica window are presented as an example of the technique's capabilities. This high‐gradient element serves as a thermal correction plate in the High‐Repetition‐Rate Advanced Petawatt Laser System (HAPLS) currently being built at Lawrence Livermore National Laboratory. OCIS codes: (140.0140) Lasers and laser optics; (140.3300) Laser beam shaping; (220.0220) Optical design and fabrication; (220.1000)

Developing magnetorheological finishing (MRF) technology for the manufacture of large-aperture optics in megajoule class laser systems

Laser-Induced Damage in Optical Materials: 2010, 2010

ABSTRACT Over the last eight years we have been developing advanced MRF tools and techniques to m... more ABSTRACT Over the last eight years we have been developing advanced MRF tools and techniques to manufacture meter-scale optics for use in Megajoule class laser systems. These systems call for optics having unique characteristics that can complicate their fabrication using conventional polishing methods. First, exposure to the high-power nanosecond and sub-nanosecond pulsed laser environment in the infrared (>27 J/cm2 at 1053 nm), visible (>18 J/cm2 at 527 nm), and ultraviolet (>10 J/cm2 at 351 nm) demands ultra-precise control of optical figure and finish to avoid intensity modulation and scatter that can result in damage to the optics chain or system hardware. Second, the optics must be super-polished and virtually free of surface and subsurface flaws that can limit optic lifetime through laser-induced damage initiation and growth at the flaw sites, particularly at 351 nm. Lastly, ultra-precise optics for beam conditioning are required to control laser beam quality. These optics contain customized surface topographical structures that cannot be made using traditional fabrication processes. In this review, we will present the development and implementation of large-aperture MRF tools and techniques specifically designed to meet the demanding optical performance challenges required in large aperture high-power laser systems. In particular, we will discuss the advances made by using MRF technology to expose and remove surface and subsurface flaws in optics during final polishing to yield optics with improve laser damage resistance, the novel application of MRF deterministic polishing to imprint complex topographical information and wavefront correction patterns onto optical surfaces, and our efforts to advance the technology to manufacture largeaperture damage resistant optics.

EPRFIT: An electron paramagnetic resonance modeling and analysis package Version 1. 10. Technical report

Unknown, Dec 1, 1991

EPRFIT is a computerized analysis and modeling package which simulates isotropic EPR spectra. The... more EPRFIT is a computerized analysis and modeling package which simulates isotropic EPR spectra. The package performs first and second order spectral simulations of both single configuration species and exchange-broadened species containing up to 7 exchanging configurations. The program simulates spectra composed of up to 2200 individual lines and up to 14 distinct spin species with nuclear spins within the range 0-9.5. The various procedures within the program are accessed via a user friendly menu-based package. Data entry is conducted using a spreadsheet architecture which provides the user with easy access to data for inspection and editing. Simulation data, simulated spectra, and experimental/simulated spectrum comparison files can be retrieved and stored onto hard/floppy disk storage in either ASCII or packed formats. ASCII output provides a useful means for linking the data/spectra to other analysis packages as well as for use in printing/plotting routines. The simulated and comparison spectra can also be displayed and analyzed graphically within the program. Spectral analysis options include spectrum offsetting, panning, zooming, and peak position and intensity identification routines. These operations apply to both simulated and comparison spectra. Hardcopies of the simulation results and any combination of spectra can be printed onto Epson compatible dot matrix printers for future reference or presentation.

Method and System for Processing Optical Elements Using Magnetorheological Finishing

This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-ind... more This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-induced surface damage sites on large-aperture fused silica optics. We will show the effect of various 355-nm laser conditioning methodologies on the reduction of surface-damage initiation in fused silica samples that have varying qualities of polishing. With the best, generally available fused silica optic, we have demonstrated that 355-nm laser conditioning can achieve up to 10x reduction in surface damage initiation concentration in the fluence range of 10-14 J/cm 2 (355-nm @ 3 ns).

Van der Waals clusters of aromatic molecules studied using supersonic molecular jet spectroscopy

ABSTRACT

Laser-Induced Damage in Optical Materials: 2003, 2004

Magnetorheological finishing (MRF) techniques have been developed to manufacture continuous phase... more Magnetorheological finishing (MRF) techniques have been developed to manufacture continuous phase plates (CPP's) and custom phase corrective structures on polished fused silica surfaces. These phase structures are important for laser applications requiring precise manipulation and control of beam-shape, energy distribution, and wavefront profile. The MRF's unique deterministic-sub-aperture polishing characteristics make it possible to imprint complex topographical information onto optical surfaces at spatial scale-lengths approaching 1 mm. In this study, we present the results of experiments and model calculations that explore imprinting two-dimensional sinusoidal structures. Results show how the MRF removal function impacts and limits imprint fidelity and what must be done to arrive at a high quality surface. We also present several examples of this imprinting technology for fabrication of phase correction plates and CPPs for use at high fluences.

Large-aperture diffractive optical elements for high power laser and space applications

Frontiers in Optics 2004/Laser Science XXII/Diffractive Optics and Micro-Optics/Optical Fabrication and Testing, 2004

Laser-Induced Damage in Optical Materials: 2005, 2005

ABSTRACT Antireflection (AR) coatings typically damage at the interface between the substrate and... more ABSTRACT Antireflection (AR) coatings typically damage at the interface between the substrate and coating. Therefore the substrate finishing technology can have an impact on the laser resistance of the coating. For this study, AR coatings were deposited on Yb:S-FAP [Yb3+:Sr5(PO4)3F] crystals that received a final polish by both conventional pitch lap finishing as well as magnetorheological finishing (MRF). SEM images of the damage morphology reveals laser damage originates at scratches and at substrate coating interfacial absorbing defects. Previous damage stability tests on multilayer mirror coatings and bare surfaces revealed damage growth can occur at fluences below the initiation fluence. The results from this study suggest the opposite trend for AR coatings. Investigation of unstable HR and uncoated surface damage morphologies reveals significant radial cracking that is not apparent with AR damage due to AR delamination from the coated surface with few apparent cracks at the damage boundary. Damage stability tests show that coated Yb:S-FAP crystals can operate at 1057 nm at fluences around 20 J/cm2 at 10 ns; almost twice the initiation damage threshold.

Laser Beam Shaping IX, 2008

Laser-Induced Damage in Optical Materials: 2001, 2002

This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-ind... more This paper describes the effect of 355-nm laser conditioning on the concentration of UV-laser-induced surface damage sites on large-aperture fused silica optics. We will show the effect of various 355-nm laser conditioning methodologies on the reduction of surface-damage initiation in fused silica samples that have varying qualities of polishing. With the best, generally available fused silica optic, we have demonstrated that 355-nm laser conditioning can achieve up to 10x reduction in surface damage initiation concentration in the fluence range of 10-14 J/cm 2 (355-nm @ 3 ns).

Chemiluminescent Reaction of Tellurium with Fluorine

Laser-Induced Damage in Optical Materials: 2006, 2006

The Mercury laser uses ytterbium-doped strontium fluorapatite (Yb:S-FAP) crystals as the gain med... more The Mercury laser uses ytterbium-doped strontium fluorapatite (Yb:S-FAP) crystals as the gain medium with a nominal clear aperture of 4 x 6 cm. Recent damage test data have indicated the existence of bulk precursors in Yb:S-FAP that initiate damage starting at approximately 10 J/cm2 at 9 ns under 1064 nm irradiation. In this paper, we report on preliminary results on

Solid State Lasers XIII: Technology and Devices, 2004

We report initial operation of the Mercury laser with seven 4 x 6 cm S-FAP amplifier slabs pumped... more We report initial operation of the Mercury laser with seven 4 x 6 cm S-FAP amplifier slabs pumped by four 80 kW diode arrays. The system produced up to 33.5 J single shot, 23.5 J at 5 Hz, and 10 J at 10 Hz for 20 minute runs at 1047 nm. During the initial campaign, more than 2.8 x 104

Van der Waals modes of solute/solvent clusters: benzene-methane, -deuteriomethane, and -carbon tetrafluoride

The Journal of Physical Chemistry, 1987

ABSTRACT

Photochemical and thermochemical decomposition of 3-nitro-1,2,4-triazol-5-one and perdeuterio-3-nitro- 1,2,4-triazol-5-one in neat and mixed systems. (Reannouncement with new availability information)

The Journal of Physical Chemistry, 1991

... Chem. 1985.89,4809. (f) Shackelford. S. A.; Goshgarian, BB; Chapman, RD; Askins, RE; Flanigan... more ... Chem. 1985.89,4809. (f) Shackelford. S. A.; Goshgarian, BB; Chapman, RD; Askins, RE; Flanigan, DA; Rogers, RN Propellants, Explos. Pyrotech. 1989,14,93. ... Shackelford, SA J. Phys. (Paris) 1987, 48, C4-193. (7) (a) Menapace, JA; Marlin, JE J . Phys. Chem. 1990,94,1906. ...

Public reporting burden for this collection of information is estimated to average 1 hour per res... more Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. , and partially deuterium-labeled DNNC-d 2 and DNNC-d 4 isotopomers were obtained by isothermal differential scanning calorimetry (IDSC). Molecular kinetic deuterium isotope effect (KDIE) values obtained with DNNC and DNNC-d 6 from 174 to 194 o C revealed that C-H bond rupture regulates both an endothermic catalytic initiation and the exothermic propagation of the liquid thermochemical decomposition process. Using IDSC-based KDIE comparisons with the DNNC-d 2 , DNNC-d 4 , and DNNC-d 6 isotopomers, a more detailed chemical structure/mechanistic relationship emerged by entering the interior of the DNNC molecule. Here structural kinetic KDIE results showed the rate-controlling C-H bond rupture has its origin at the non-equivalent C-2 methylene group sandwiched between the two nitrated DNNC nitrogen ring atoms, versus at the chemically equivalent C-4 and C-6 methylene ring positions located elsewhere in the DNNC molecule. Elucidation of such mechanistic features should aid in the structural design of new high energy compounds with improved thermochemical properties. A 170.0 kJ/mol activation energy appeared for the endothermic induction period, and a lower 104.2 kJ/mol activation energy was determined for the exothermic acceleratory portion of the DNNC decomposition process. The global liquid and solid state thermochemical decomposition processes for DNNC are compared. a. REPORT b. ABSTRACT c. THIS PAGE 19b. TELEPHONE NUMBER (include area code) SAR 62 N/A Unclassified Unclassified Unclassified Standard Form 298 (Rev. 8-98) __________________________________________________________________________ Abstract Global kinetics for the liquid state thermochemical decomposition of neat 1,3,5,5tetranitrohexahydropyrimidine (DNNC), perdeuterio-labeled DNNC-d 6 , and partially deuterium-labeled DNNC-d 2 and DNNC-d 4 isotopomers were obtained by isothermal differential scanning calorimetry (IDSC). Molecular kinetic deuterium isotope effect (KDIE) values obtained with DNNC and DNNC-d 6 from 174 to 194 o C revealed that C-H bond rupture regulates both an endothermic catalytic initiation and the exothermic propagation of the liquid thermochemical decomposition process. Using IDSC-based KDIE comparisons with the DNNC-d 2 , DNNC-d 4 , and DNNC-d 6 isotopomers, a more detailed chemical structure/mechanistic relationship emerged by entering the interior of the DNNC molecule. Here structural kinetic KDIE results showed the rate-controlling C-H bond rupture has its origin at the non-equivalent C-2 methylene group sandwiched between the two nitrated DNNC nitrogen ring atoms, versus at the chemically equivalent C-4 and C-6 methylene ring positions located elsewhere in the DNNC molecule. Elucidation of such mechanistic features should aid in the structural design of new high energy compounds with improved thermochemical properties. A 170.0 kJ/mol activation energy appeared for the endothermic induction period, and a lower 104.2 kJ/mol activation energy was determined for the exothermic acceleratory portion of the DNNC decomposition process. The global liquid and solid state thermochemical decomposition processes for DNNC are compared.

Combined advanced finishing and UV laser conditioning process for producing damage resistant optics