Reflective Inc

WE PROPOSE A COMPREHENSIVE EXPERIMENTAL RESEARCH PROGRAM WHOSE TWO MAIN GOALS ARE (A) TO IMPROVE THE PERFORMANCE OF HARD XRAY MULTILAYER COATINGS AND (B) TO DEVELOP A HIGH-THROUGHPUT METHOD TO CORRECT MID-FREQUENCY SURFACE ERRORS IN THIN-SHELL MIRROR SUBSTRATES. ACHIEVING THESE GOALS WILL ENABLE THE COST-EFFECTIVE CONSTRUCTION OF LIGHT-WEIGHT HIGHLY-NESTED X-RAY TELESCOPES HAVING GREATER OBSERVATIONAL SENSITIVITY WIDER ENERGY COVERAGE AND HIGHER ANGULAR RESOLUTION THAN CAN BE ACHIEVED AT PRESENT. THE REALIZATIONOF THIS TECHNOLOGY WILL THUS BENEFIT THE DEVELOPMENT OF A VARIETY OF EXPLORER-CLASS NASA X-RAY ASTRONOMY MISSIONS NOW BEING FORMULATED FOR BOTH THE SOFT AND HARD X-RAY BANDS AND WILL ENABLE THE CONSTRUCTION OF FUTURE FACILITY-CLASS X-RAY MISSIONS THAT WILL REQUIRE BOTH HIGH SENSITIVITY AND HIGH RESOLUTION. BUILDING ON THE SUCCESS OF OUR PREVIOUS APRA-FUNDED RESEARCH WE PLAN TO INVESTIGATE NEW THIN-FILM GROWTH TECHNIQUES NEW MATERIALS AND NEW APERIODIC COATING DESIGNS IN ORDER TO DEVELOP NEW HARD X-RAY MULTILAYERSTHAT HAVE HIGHER X-RAY REFLECTANCE WIDER ENERGY RESPONSE LOWER FILM STRESS AND GOOD STABILITY AND THAT CAN BE PRODUCED MORE QUICKLY AT REDUCED COST. ADDITIONALLY WE PROPOSE TO BUILD UPON OUR EXTENSIVE EXPERIENCE IN SUB-NM FILM-THICKNESS CONTROL USING VELOCITY MODULATION AND MASKED DEPOSITION TECHNIQUES AND IN THE RECENT DEVELOPMENT OF LOW-ROUGHNESS LOW-STRESS FILMS GROWN BY REACTIVE SPUTTERING IN ORDER TO DEVELOP NEW METHODS FOR CORRECTING MID-FREQUENCY SURFACE ERRORS IN THIN-SHELL MIRROR SUBSTRATESUSING BOTH DIFFERENTIAL DEPOSITION AND ION-BEAM FIGURING EITHER ALONE OR IN COMBINATION. THESE TWO SURFACE-CORRECTION TECHNIQUES ALREADY BEING USED FOR SUB-NM FIGURING OF PRECISION OPTICS IN A VARIETY OF DISCIPLINES INCLUDING DIFFRACTION-LIMITED EUV LITHOGRAPHY ANDSYNCHROTRON APPLICATIONS REQUIRING SUB-MICRON FOCUSING ARE IDEALLY SUITED FOR CONTROLLING MM-SCALE SURFACE ERRORS IN THE THIN-SHELL SUBSTRATES USED FOR ASTRONOMICAL X-RAY TELESCOPES. IN ORDER TO ACHIEVE HIGH-THROUGHPUT PROCESSING USING THESE TECHNIQUES WE PROPOSE TO DEVELOP A NOVEL APPROACH USING AN ELECTRONICALLY-ACTUATED APERTURE MECHANISM TO ACTIVELY CONTROL THE SHAPE OF A LONG RECTANGULAR MM-SCALE BEAM OF ADATOM OR IONS AS THE SUBSTRATE MOVES PAST AT CONSTANT VELOCITY THEREBY ENABLING EFFICIENT TWO-DIMENSIONAL FIGURE CORRECTION OF MULTIPLE SHELLS SIMULTANEOUSLY.

THE OVERARCHING CHALLENGE ADDRESSED BY THIS PROPOSAL IS THE DEVELOPMENT OF HIGH-REFLECTANCE HIGH-RESOLUTION X-RAY MIRRORS TO BE USED FOR THE CONSTRUCTION OF LIGHTWEIGHT X-RAY TELESCOPES FOR FUTURE NASA ASTRONOMY MISSIONS SUCH AS LYNX AND OTHERS. THE PROPOSAL'S TWO SPECIFIC AIMS ARE: 1) THE DEVELOPMENT OF OPTIMIZED IRIDIUM-BASED INTERFERENCE COATINGS FOR THE 0.1 10 KEV BAND; AND 2) THE DEVELOPMENT OF METHODS TO MITIGATE COATING-STRESS-INDUCED SUBSTRATE DEFORMATIONS IN THIN-SHELL GLASS AND SI MIRROR SEGMENTS. THESE GOALS WILL BE ACHIEVED BY BUILDING ON ESTABLISHED FILM DEPOSITION TECHNIQUES AND METROLOGY INFRASTRUCTURE FOR X-RAY OPTICS THAT HAVE BEEN DEVELOPED AND ADVANCED BY THE PI THROUGH APRA FUNDING SINCE 1999. SPECIFIC AIM #1: INTERFERENCE COATINGS FOR THE 0.1 10 KEV ENERGY BAND TELESCOPE EFFECTIVE AREA CAN BE MAXIMIZED BY USING IR-BASED REFLECTIVE COATINGS THAT EXPLOIT OPTICAL INTERFERENCE TO PROVIDE HIGHER REFLECTANCE THAN IR ALONE. HOWEVER ONLY PRELIMINARY INVESTIGATIONS OF SUCH COATINGS HAVE BEEN CONDUCTED THUS FAR; MORE RESEARCH IS REQUIRED TO FULLY OPTIMIZE THESE COATINGS FOR MAXIMUM PERFORMANCE TO EXPERIMENTALLY DETERMINE THE COATING DESIGNS THAT ARE FEASIBLE AND TO DETERMINE THE ACHIEVABLE X-RAY REFLECTANCE FILM STRESS SURFACE ROUGHNESS AND THERMAL AND TEMPORAL STABILITY. THE FIRST SPECIFIC AIM OF THIS PROPOSAL IS TO REACH THESE VERY GOALS THROUGH A COMPREHENSIVE RESEARCH PROGRAM. DEMONSTRATION OF THE ACHIEVABLE REFLECTANCE STRESS AND ROUGHNESS IN STABLE OPTIMIZED COATINGS WILL IN TURN FACILITATE GLOBAL TELESCOPE DESIGN OPTIMIZATION BY IDENTIFYING THE BEST COATING FOR EACH MIRROR SHELL BASED ON INCIDENCE ANGLE AND ON TELESCOPE EFFECTIVE-AREA AND FIELD-OF-VIEW REQUIREMENTS. THE RESEARCH HAS THE POTENTIAL TO GREATLY INCREASE THE EFFECTIVE AREA OF FUTURE X-RAY TELESCOPES. SPECIFIC AIM #2: MITIGATION OF COATING-STRESS-INDUCED SUBSTRATE DEFORMATIONS HIGH-QUALITY FILMS OF IR AND OTHER CANDIDATE MATERIALS (E.G. B4C) TO BE INVESTIGATED FOR THE 0.1 10 KEV BAND DEPOSITED BY MAGNETRON SPUTTERING HAVE HIGH DENSITY AND LOW ROUGHNESS AND THUS GOOD X-RAY PERFORMANCE. HOWEVER IR B4C AND CERTAIN OTHER MATERIALS HAVE EXCEEDINGLY HIGH FILM STRESS WHEN DEPOSITED UNDER CONDITIONS FOR MAXIMUM REFLECTANCE. RESIDUAL FILM STRESS IN THE X-RAY REFLECTIVE COATINGS CAN DEFORM THIN-SHELL MIRROR SEGMENTS LEADING TO UNACCEPTABLE DEGRADATION OF ANGULAR RESOLUTION. COATING STRESS WAS NOT AN ISSUE FOR CHANDRA. BUT FOR LYNX FOR EXAMPLE THE SUBSTRATES WILL BE ~50X THINNER AND SO SUB-ARC-SECOND RESOLUTION SIMPLY CANNOT BE ACHIEVED USING THIN-SHELL MIRROR SEGMENTS WITHOUT THE DEVELOPMENT OF NON-DEFORMING COATINGS. THE SECOND SPECIFIC AIM OF THIS PROPOSAL IS TO DEVELOP TECHNIQUES TO MITIGATE COATING-STRESS-INDUCED DEFORMATIONS IN GLASS AND SI SHELL SEGMENTS. TWO POTENTIAL SOLUTIONS WILL BE INVESTIGATED: A) NEW DEPOSITION METHODS TO CONTROL COATING THICKNESS UNIFORMITY AND NET FILM STRESS IN TWO DIMENSIONS WILL BE USED TO DETERMINE IF ALREADY-DEVELOPED ZERO-NET-STRESS IR-BASED COATINGS AS WELL AS THE NEW REFLECTIVE COATINGS TO BE DEVELOPED CAN BE DEPOSITED ONTO SHELL SEGMENTS WITHOUT INDUCING UNACCEPTABLE SUBSTRATE DEFORMATIONS A QUESTION THAT HAS NOT YET BEEN DEFINITIVELY ADDRESSED; IF UNIFORM COATINGS HAVING SUFFICIENTLY LOW DEFORMATION CANNOT BE REALIZED THEN NON-UNIFORM COATINGS WILL BE INVESTIGATED WHERE SPATIAL CONTROL OF NET FILM STRESS IN 2D WILL COMPENSATE FOR POTENTIAL NON-UNIFORM DEFORMATIONS. IF SUCCESSFUL THE EFFECTIVENESS OF THE APPROACH WITH MORE COMPLEX INTERFERENCE COATINGS WILL ALSO BE ESTABLISHED. B) A MORE GENERAL (ALBEIT MORE COMPLEX) METHOD OF MITIGATING STRESS-INDUCED DEFORMATIONS WILL BE INVESTIGATED SPECIFICALLY THE USE OF BALANCED FRONT- AND BACKSIDE COATINGS A TECHNIQUE THAT IF SUCCESSFUL CAN BE USED IN PRINCIPLE WITH ANY TYPE OF COATING (IR-BASED HIGH-ENERGY MULTILAYERS ETC.) REGARDLESS OF ITS STRESS STATE. (THE APPROACH IS LIKELY INCOMPATIBLE WITH ACTIVE CORRECTION HOWEVER.)

HIGH-PERFORMANCE MULTILAYER COATINGS FOR THE NEXT GENERATION OF ASTRONOMICAL X-RAY OPTICS-PHASE II:THIS PROPOSAL IS DIRECTED AT THE CONTINUED DEVELO

WE PROPOSE TO DEVELOP APERIODIC MULTILAYER COATINGS HAVING HIGH REFLECTANCE AT NORMAL INCIDENCE OVER A BROAD SPECTRAL BAND IN THE EXTREME ULTRAVIOLET (EUV) FOR SPECTROSCOPY OF THE SOLAR ATMOSPHERE. THE SPECTRAL REGION FROM APPROXIMATELY 17 NM TO 35 NM CONTAINS A NUMBER OF SCIENTIFICALLY IMPORTANT EMISSION LINES EMANATING FROM THE SOLAR CORONA AND TRANSITION REGION. THE REALIZATION OF BROADBAND EUV MULTILAYER COATINGS HAVING HIGH REFLECTANCE OVER ALL OR PART OF THIS BAND WILL ENABLE THE CONSTRUCTION OF HIGH-RESOLUTION SPECTROMETERS BASED ON NORMAL-INCIDENCE GRATINGS HAVING WIDE WAVELENGTH COVERAGE AND SENSITIVITY THAT IS SUFFICIENT TO SUPPORT THE EXPOSURE TIMES AND CADENCES NEEDED FOR FUTURE NASA SOLAR PHYSICS AND SPACE WEATHER MISSIONS. THE HINODE/EIS INSTRUMENT TARGETED THE SPECTRAL BAND FROM 25 NM TO 29 NM USING A NORMAL-INCIDENCE GRATING COATED WITH A PERIODIC SI/MO MULTILAYER. APERIODIC COATINGS DEVELOPED IN RECENT YEARS CAN NOW BE DESIGNED TO PROVIDE HIGH REFLECTANCE OVER A MUCH WIDER RANGE OF WAVELENGTHS. FURTHERMORE NEWLY DEVELOPED MG- AND AL-BASED MULTILAYER COATINGS HAVE BEEN DEMONSTRATED TO HAVE SIGNIFICANTLY HIGHER REFLECTANCE THAN SI/ MO MULTILAYERS IN THIS SPECTRAL REGION. WE THUS PROPOSE TO DEVELOP NEW MG- AND AL-BASED APERIODIC MULTILAYERS HAVING NEARLY FLAT RESPONSE OVER A MUCH WIDER WAVELENGTH BAND THAN CAN BE CAPTURED USING PERIODIC MULTILAYERS THEREBY ENABLING SIGNIFICANT INCREASES IN WAVELENGTH COVERAGE IN FUTURE SPECTROSCOPY INSTRUMENTS. THE PROPOSED RESEARCH WILL FOCUS ON SEVERAL NEW MG- AND AL-BASED MULTILAYER MATERIAL SYSTEMS THAT HAVE BEEN DEVELOPED OVER THE PAST DECADE INCLUDING THE THREE-MATERIAL SYSTEMS ZR/CO/MG SIC/MO/AL AND B4C/MO/AL. GOOD EUV PERFORMANCE AND STABILITY HAVE BEEN DEMONSTRATED ALREADY WITH PERIODIC (I.E. NARROW-BAND) COATINGS COMPRISING EACH OF THESE MATERIAL COMBINATIONS. WE WILL DEVELOP APERIODIC BROAD-BAND COATINGS USING THE SAME MATERIAL COMBINATIONS FOLLOWING A SYSTEMATIC EXPERIMENTAL WORK PLAN. CANDIDATE COATINGS WILL BE DEPOSITED BY MAGNETRON SPUTTERING AND COATING MICROSTRUCTURE STRESS ROUGHNESS EUV REFLECTANCE STABILITY AND OTHER RELEVANT PROPERTIES WILL BE FULLY CHARACTERIZED. THE EXPERIMENTAL WORK WILL BE CONDUCTED USING ESTABLISHED FACILITIES AND METHODS AND A SYSTEMATIC ITERATIVE APPROACH WILL BE FOLLOWED TO OPTIMIZE COATING PERFORMANCE. THE ANTICIPATED OUTCOME OF THE PROPOSED RESEARCH IS THE REALIZATION OF NEW BROAD-BAND MULTILAYER COATINGS OPERATING IN THE 17 35 NM BAND THAT WILL ENABLE THE CONSTRUCTION OF HIGH RESOLUTION SPECTROSCOPY INSTRUMENTS TARGETING THIS REGION OF THE EUV IN SUPPORT OF FUTURE NASA MISSIONS.

HIGH-PERFORMANCE MULTILAYER COATINGS FOR THE NEXT GENERATION OF ASTRONOMICAL X-RAY OPTICS

TO ENABLE CONSTRUCTION OF NEXT-GENERATION HARD X-RAY TELESCOPES THIS PROJECT AIMS TO (A) DEVELOP CO- NI- AND PTBASED X-RAY MULTILAYER COATINGS HAVING HIGH REFLECTANCE UP TO ~200 KEV IN ORDER TO MAXIMIZE TELESCOPE EFFECTIVE AREA AND EXTEND ENERGY COVERAGE BEYOND NUSTAR AND (B) DEVELOP TECHNIQUES TO MITIGATE MULTILAYER-COATING-STRESS-INDUCED DEFORMATION OF THIN-SHELL MIRROR SUBSTRATES IN ORDER TO ACHIEVE HARD X-RAY TELESCOPE ANGULAR RESOLUTION OF 15 ARC-SECONDS OR BETTER.

MULTILAYER X-RAY OPTICS FOR MAMMOGRAPHY

NEXT-GENERATION EUV MULTILAYER COATINGS FOR SOLAR IMAGING AND SPECTROSCOPYWE PLAN TO DEVELOP NEW EUV MULTILAYER COATINGS THAT PROVIDE HIGHER NORMAL-INCIDENCE REFLECTANCE BETTER CONTROL OF SPECTRAL BANDPASS (USING APERIODIC COATING DESIGNS) FOR IMPROVED NARROW-BAND IMAGING AND WIDE-BAND SPECTROSCOPY BETTER STABILITY AND RESISTANCE TO OXIDATION AND HARSH ENVIRONMENTS (FOR USE IN MISSIONS THAT HAVE ORBITS SUBJECTED TO A HIGH FLUX OF ENERGETIC PARTICLES FOR EXAMPLE) AND LOWER FILM STRESS TO AVOID POTENTIAL COATING FAILURES. THESE ADVANCEMENTS IN COATING PERFORMANCE WILL BE ACHIEVED THROUGH A COMPREHENSIVE EXPERIMENTAL RESEARCH PROGRAM DURING WHICH WE WILL TEST A VARIETY OF NEW MULTILAYER MATERIAL COMBINATIONS AND OPTIMIZE PERFORMANCE OF THE BEST COATINGS BY SYSTEMATICALLY ADJUSTING THE MULTILAYER DESIGN. WE WILL CHARACTERIZE THE EUV REFLECTANCE FILM STRESS AND STABILITY OF THE NEW COATINGS WE DEVELOP IN ORDER TO RAISE THEIR TECHNOLOGY READINESS LEVEL (TO TRL 4 OR 5) AND THUS QUALIFY THEIR USE IN FUTURE NASA MISSIONS.

WE PROPOSE TO CONTINUE OUR DEVELOPMENT OF TWO-DIMENSIONAL DIFFERENTIAL DEPOSITION AND EROSION A NOVEL METHODS FOR HIGH-THROUGHPUT SURFACE HEIGHT ERROR CORRECTION IN THIN-SHELL CYLINDRICAL MIRROR SUBSTRATES. WE ALSO PROPOSE TO DEVELOP NON-DISTORTING X-RAY REFLECTIVE MULTILAYER COATINGS FOR USE ABOVE 80 KEV. OUR SPECIFIC RESEARCH OBJECTIVES ARE: (A) DEVELOP TWO-DIMENSIONAL CONTROL OF FILM DEPOSITION AND EROSION TO CORRECT BOTH LOW- AND MID-FREQUENCY SURFACE HEIGHT ERRORS IN CYLINDRICAL THIN-SHELL MIRROR SUBSTRATES AND (B) DEVELOP HIGH-EFFICIENCY NON-DISTORTING ZERO NET-STRESS AND STRESS BALANCED REFLECTIVE MULTILAYER COATINGS FOR USE ABOVE 80 KEV.

WE PLAN TO DEVELOP NEW EUV MULTILAYER COATINGS THAT PROVIDE HIGHER NORMAL-INCIDENCE REFLECTANCE BETTER CONTROL OF SPECTRAL BANDPASS (USING APERIODIC COATING DESIGNS) FOR IMPROVED NARROW-BAND IMAGING AND WIDE-BAND SPECTROSCOPY BETTER STABILITY AND RESISTANCE TO OXIDATION AND HARSH ENVIRONMENTS (FOR USE IN MISSIONS THAT HAVE ORBITS SUBJECTED TO A HIGH FLUX OF ENERGETIC PARTICLES FOR EXAMPLE) AND LOWER FILM STRESS TO AVOID POTENTIAL COATING FAILURES. THESE ADVANCEMENTS IN COATING PERFORMANCE WILL BE ACHIEVED THROUGH A COMPREHENSIVE EXPERIMENTAL RESEARCH PROGRAM DURING WHICH WE WILL TEST A VARIETY OF NEW MULTILAYER MATERIAL COMBINATIONS AND OPTIMIZE PERFORMANCE OF THE BEST COATINGS BY SYSTEMATICALLY ADJUSTING THE MULTILAYER DESIGN. WE WILL CHARACTERIZE THE EUV REFLECTANCE FILM STRESS AND STABILITY OF THE NEW COATINGS WE DEVELOP IN ORDER TO RAISE THEIR TECHNOLOGY READINESS LEVEL (TO TRL 4 OR 5) AND THUS QUALIFY THEIR USE IN FUTURE NASA MISSIONS.