Year: 2024
Type: article
Abstract: The Rockets for Extended-source X-ray Spectroscopy (tREXS) are a series of suborbital rocket payloads designed to collect spectral emission from extended astronomical sources of soft X-rays. The tREXS spectrograph uses mechanical beam-shaping modules and reflection gratings to passively focus and then disperse incident X-rays to an array of Teledyne/e2v CIS 113 CMOS X-ray sensors. Designed to achieve a moderate spectral resolution, R ⪆ 50, from ≈15 to 40 Å over a large field of view (>10 deg2), the tREXS instrument is sensitive to line emission from key ion species over the soft-X-ray band. Here we present the complete end-to-end design of the tREXS spectrograph and discuss its significance and expected performance, using simulated observations of the Cygnus Loop supernova remnant and an enhanced region in the soft X-ray background.
Source: The Astrophysical Journal
Language: English
Subfield: Instrumentation
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
Awards: SEVERAL OF ASTRONOMY'S KEY FUTURE SCIENCE OBJECTIVES AS IDENTIFIED BY NASA CAN BE ACHIEVED WITH SOFT X-RAY SPECTROSCOPY. THIS STUDY SEEKS TO DEVELOP A NEW TECHNIQUE FOR FABRICATING X-RAY REFLECTION GRATINGS TO BE INTEGRATED IN FUTURE X-RAY SPECTROMETER DESIGNS. THE FABRICATION METHOD DEVELOPED IN THIS STUDY WILL CREATE A REFLECTION GRATING WITH A TRUE RADIAL PROFILE WHICH IS A REQUIREMENT IN ORDER TO ELIMINATE GRATING-INDUCED ABERRATIONS TO THE TELESCOPE FOCUS AND ACHIEVE THE REQUIRED RESOLVING POWER OF FUTURE MISSIONS. IF SUCCESSFUL THE TECHNOLOGY DEVELOPED IN THIS STUDY WILL LEAD TO THE REALIZATION OF THEORETICAL X-RAY SPECTROMETER PERFORMANCE ON TIMESCALES CONSISTENT WITH THE NEXT DECADAL SURVEY. THIS STUDY WILL BUILD ON OUR RESEARCH GROUP'S STRONG HERITAGE IN THE DEVELOPMENT OF X-RAY REFLECTION GRATINGS AND INTRODUCE A NEW FABRICATION TECHNIQUE THAT RETAINS CURRENT STATE-OF-THE-ART GRATING EFFICIENCY WHILE ALSO ACHIEVING ORDER-OF-MAGNITUDE IMPROVEMENTS IN RESOLVING POWER. THE NEW FABRICATION TECHNIQUE IS CENTERED AROUND PIEZOELECTRIC MATERIALS AND WILL BE APPROACHED AS FOLLOWS: FIRST I WILL MODEL GRATING APPLICATIONS OF PIEZOELECTRIC MATERIALS AND CONDUCT TRADE-STUDY TO DETERMINE MOST SUITABLE PIEZOELECTRIC MATERIALS TO BE USED IN GRATING FABRICATION. I WILL THEN OBTAIN MATERIALS AND BEGIN IMPLEMENTATION OF THE PLANNED FABRICATION PROCEDURES: CREATE A "MASTER" GRATING WITH PARALLEL GROOVES CURRENT ELECTRON-BEAM LITHOGRAPHY (EBL) EMPLOYED IN OUR GRATING FABRICATION EFFORTS IN ORDER TO RETAIN THE PRECISE GROOVE FACETS ACHIEVABLE WITH EBL; THE EBL "MASTER" WILL THEN BE IMPRINTED INTO A SOFT RESIST THAT IS COATED UPON A WAFER OF PIEZOELECTRIC MATERIAL BENEATH WHICH ARE ELECTRODES TO CONTROL THE CURRENT THROUGH THE MATERIAL; WITH THE PARALLEL-GROOVE PROFILE IMPRINTED INTO THE RESIST A VARIABLE CURRENT WILL BE APPLIED ACROSS THE PIEZOELECTRIC MATERIAL TO FORCE THE RESIST TO CONFORM TO A PRESELECTED PATTERN WHICH WILL TRANSFORM THE PARALLEL GROOVES INTO A RADIAL PROFILE WITHOUT SACRIFICING THE PRECISE FACETS INTRODUCED IN THE ORIGINAL EBL WRITE; THE PATTERN WILL THEN BE UV-CURED IN ORDER TO SOLIDIFY THE RESIST AND LOCK THE RADIAL PROFILE INTO PLACE; FINALLY THIS NEW PIEZOELECTRIC MASTER WILL BE USED TO IMPRINT DOZENS OF REPLICAS. THE ENTIRE PROCESS WILL CERTAINLY REQUIRE A SIGNIFICANT AMOUNT OF DEVELOPMENT AND TRIAL-AND-ERROR WHICH INCLUDES TESTING INTERMEDIATE PROTOTYPES AT NASA CENTERS FOR BOTH EFFICIENCY AND RESOLUTION. HOWEVER IF IMPLEMENTED SUCCESSFULLY THIS TECHNOLOGY WILL MAKE POSSIBLE BOTH THE ORDER-OF-MAGNITUDE GAINS IN EFFECTIVE AREA AND RESOLVING POWER OVER CURRENT OBSERVATORIES THAT IS REQUIRED FOR FUTURE X-RAY MISSIONS., G4134240449, G7554570441, THE SOFT X-RAY BACKGROUND SURROUNDS OUR LOCAL GALACTIC ENVIRONMENT YET VERY LITTLE IS KNOWN ABOUT THE PHYSICAL CHARACTERISTICS OF THIS PLASMA. A HIGH-RESOLUTION SPECTRUM COULD UNLOCK THE PROPERTIES OF THIS MILLION DEGREE GAS BUT THE DIFFUSE LOW INTENSITY NATURE OF THE BACKGROUND HAVE MADE IT DIFFICULT TO OBSERVE ESPECIALLY WITH A DISPERSIVE SPECTROGRAPH. PREVIOUS OBSERVATIONS HAVE RELIED ON X-RAY DETECTOR ENERGY RESOLUTION WHICH PRODUCES POORLY DEFINED SPECTRA THAT ARE POORLY FIT BY COMPLEX PLASMA MODELS. HERE WE PROPOSE A SERIES OF SUBORBITAL ROCKET FLIGHTS THAT WILL BEGIN THE CHARACTERIZATION OF THIS ELUSIVE SOURCE THROUGH HIGH-RESOLUTION X-RAY GRATING SPECTROSCOPY. THE ROCKET-BASED SPECTROGRAPH CAN RESOLVE INDIVIDUAL EMISSION LINES OVER THE SOFT X-RAY BAND AND PLACE TIGHT CONSTRAINTS ON THE TEMPERATURE DENSITY ABUNDANCE IONIZATION STATE AND AGE OF THE PLASMA. THESE PAYLOADS WILL DRAW HEAVILY FROM THE HERITAGE GAINED FROM PREVIOUS ROCKET MISSIONS WHILE ALSO BENEFITING FROM RELATED NASA TECHNOLOGY DEVELOPMENT PROGRAMS. THE PENNSYLVANIA STATE UNIVERSITY (PSU) TEAM HAS A HISTORY OF DESIGNING AND FLYING SPECTROMETER COMPONENTS ONBOARD ROCKETS WHILE ALSO BEING SCIENTIFIC LEADERS IN THE FIELD OF DIFFUSE SOFT X-RAY ASTRONOMY. THE PSU PROGRAM WILL PROVIDE HANDS-ON TRAINING OF YOUNG SCIENTISTS IN THE TECHNIQUES OF INSTRUMENTAL AND OBSERVATIONAL X-RAY ASTRONOMY. THE PROPOSED ROCKET PROGRAM WILL ALSO EXPOSE THESE RESEARCHERS TO A FULL EXPERIMENT CYCLE DESIGN FABRICATION TOLERANCE ANALYSIS ASSEMBLY FLIGHT-QUALIFICATION CALIBRATION INTEGRATION LAUNCH AND DATA ANALYSIS USING A COMBINATION OF TECHNOLOGIES SUITABLE FOR ADAPTATION TO NASA'S MAJOR MISSIONS. THE PSU PROGRAM IN SUBORBITAL X-RAY ASTRONOMY REPRESENTS AN EXCITING MIX OF COMPELLING SCIENCE HERITAGE CUTTING-EDGE TECHNOLOGY DEVELOPMENT AND TRAINING OF FUTURE SCIENTISTS.
OpenAlex ID: W4401650348