Fabrication Tests (figure and surface quality) Profilometry Interferometric Tests Image Quality and Resolution Tests Standard resolution tests Star tests and Hartman/Screen Tests Stray Light Vignetting Off-field noise (veiling glare) Testing Accomplishments
Direct diamond turn plastic (PMMA) blanks: In-process cooling by N2 (or alternative: ELID) Mounting double sided Fresnel lens such that the first side does not get damaged: prototype success Tolerances on surface roughness, de-centration errors, and facet radii found as forgiving (~ 1 cm) Determine the best way to cut curved Fresnel lens Manufacturing Accomplishments
UAH/MSFC Manufacturing Efforts 80 cm MSFC optics 20 cm UAH optics 1.3 m copper replication master on MSFC Diamond Turning machine Diamond Turning UAH optics
40 cm Prototype Manufactured at RIKEN 40cm Test at UAH Cherenkov Observation with 40cm in Japan 40cm Prototype
Image Results from 40 cm RIKEN Test 337 nm, 20O 337 nm, 0O 337 nm, 10O • 0º, 10º, 20º, 25º, 30º fields with respect to the optical axis • wavelengths 337, 365, 394, 450, 500, 550 nm • Tests included: • Optical characterization, Image quality analysis, Radiometric measurements 1951 Air Force Optical Target 337 nm, 30O
Molds for Hot Press Replication Process Four plates will be delivered by RIKEN for each lens: - two smooth for forming base Radius Of Curvature - two for pressing Fresnel surface grooves MSFC : Direct Diamond Turn Radius 0 – 750mm RIKEN: Inner Ring Mold MSFC: Produce 24 Segments Radius 750 – 1000mm RIKEN: Outer Ring Mold MSFC: Produce 24 Segments Radius 1000 – 1250mm
Shaping of Plexiglass to base curvature • Non-contact method for pre- forming plexiglass • Method has been used commercially for 1 cm thick plastics • 2 cm thick blanks have been manufactured and are currently undergoing metrology and stress testing
Nominal + L1 S1 - + L1 S2 - + L2 S1 - + L2 S2 - + Focal Plane - Tolerance Analysis for EUSO Optics Results from varying Fresnel and Focal surface base radius ( +/-2% )
Tolerance Analysis for EUSO Optics Fresnel radius and on Focal surface radius (2%) Fresnel base curvature Lens 1 Surface 1 & Lens 2 Surface 1 (2%) Lens thickness (0.5, 1.0, 1.5, 2.0 mm) Refractive index (0.3 % & 0.17 %) Surface displacement in x (5, 10 mm) Surface displacement in y (5 mm) First or second lens displacement in x, y & z (5, 10 mm) Tilt first surfaces of lenses (wedge 2 mm) Lens tilt in x & y (0.01 rad)
Preliminary Metering Structure Mass Estimate Rings Struts and Cross braces Ribs • Mass of Fresnel Lenses: • 20 mm thick PMMA lenses 236 kg • 20 mm thick TPX lenses 164 kg • Mass of Optical Structure • Graphite Fiber Re-enforced Polymer • 24 Ribs/lens x 2 lenses 88 kg • 12 metering struts with cross braces 63 kg • 3 rings/lens x 2 lenses 65 kg • 15% Contingency 30 kg • 250 kg
Mission of Opportunity Schedule AO release July 16, 2001 Preproposal Conference Aug. 10, 2001 Notice of Intent to Propose due Aug. 17, 2001 Proposal submittal due by 4 pm EST Oct. 30, 2001 Non-U.S. Letter(s) of Endorsement due Nov. 9, 2001 Selections for Phase A Concept Study (target) April 2002 Award for Phase A Concept Study (target) May 2002 Phase A Concept Study Report due (target) Sept. 2002 Downselections for Flight (target) Dec. 2002 Dates in Red may change due to 9/11/01 events
Mission of Opportunity Comments Depending on the availability of proposals of appropriate merit, NASA intends to select two MIDEX missions, one to launch by December 2006, and one to launch by December 2007. NASA is soliciting Missions of Opportunity through this AO where a commitment from NASA is required by the sponsoring organization before December 31, 2003. The launch dates may be at any time. Missions of Opportunity requiring later commitment dates should propose in response to a subsequent Explorer program AO. It is anticipated that up to four MIDEX missions will be selected for concept studies. Each MIDEX Phase A study will be funded up to $400K in real year dollars. NASA may also select investigations that will be awarded contracts to conduct concept studies for Missions of Opportunity. Each Mission of Opportunity Phase A study will be funded up to $250K in real year dollars.
Mission of Opportunity Phase 2 For phase 2, NASA will conduct a detailed review of the Phase A concept study results to evaluate the implementing details of the selected investigations, namely, any modifications of the scientific objectives, the proposed cost to NASA, design details of the investigation hardware, plans for mission implementation including all technical and management factors, details of the education and public outreach programs, plans for any new/advanced technology, and plans for participation of small disadvantaged businesses and minority institutions. As a result of this second evaluation, NASA intends to select two MIDEX investigations, and possibly one or more Mission(s) of Opportunity, for implementation leading to flight.
EUSO US Investigators Dr. James H. Adams, Jr.: Dr. Adams is an experimental cosmic ray physicist at Marshall Space Flight Center (MSFC). He will serve as PI and will be responsible for leading the U.S. EUSO team.. He has participated in, or lead, five international collaborations, three involving satellite launches. Prof. Katsushi Arisaka: Prof. Arisaka is a cosmic ray physicist and an expert on vacuum photon detectors on the faculty of UCLA. He will advise on the design of the EUSO focal plane. Dr. Mark Christl: Dr. Christl is a cosmic ray physicist at MSFC. He will do radiation effects testing of the optical components and oversee the design, procurement, and testing of the optical filters.
EUSO US Investigators Dr. Henry Crawford: Dr. Crawford is an experimental physicist and instrumentation expert at the University of California (Berkeley) Space Sciences Laboratory (SSL). He will work on shower development and EUSO signal simulations and provide advice on the electronics and trigger system. Prof. Steven Csorna: Prof. Csorna is an experimental physicist on the faculty of Vanderbilt University. He will lead the U.S. contribution to the EUSO simulation work. Prof. David Cline: Prof. Cline is an experimental physicist on the faculty of UCLA. His major focus is on astroparticle physics. He will be responsible for leading the U.S. effort to develop track reconstruction software for the production data analysis code. Prof. Carl Pennypacker: Prof. Pennypacker is an astrophysicist and supernova expert at the SSL. He is the founder of the Hands-On Universe Project. He will lead our EPO effort
EUSO US Investigators Prof. Toshiki Tajima: Prof. Tajima is a plasma physicist on the faculty of the University of Texas (U of T) and an expert in particle acceleration in plasmas. He will participate in interpretation of the data. Prof. Yoshiyuki Takahashi: Prof. Takahashi is an experimental cosmic ray physicist on the faculty of UAH. He conceived the optics for EUSO. Prof. Takahashi will serve as instrument scientist for the optical system and filters. Prof. Tom Weiler: Professor Weiler is a theoretical physicist on the faculty of Vanderbilt University. He has developed models for EECR sources. He will lead the theoretical effort to interpret the data. Mr. John Watts: Mr. Watts is a cosmic ray physicist at MSFC with years of experience in simulations. He will contribute to the EUSO simulation effort.
US Proposed Contribution Hardware The US is proposing to provide the Optical System (OS) and Filter System (FS). The OS consists of the fresnel lenses and a optical metering structure. Flight and protoflight units will be provided to ESA for integration into the EUSO instrument. Filters, prepared to be applied to the focal-plane array. will be provided to our Japanese collaborators who will install them. Design Considerations The UAH and SOMTC team members will use simulations to analyze and optimize the cost-benefit relationship for different optical and focal plane designs in relation to the overall detector capability. The parameters to be optimized include: (a) Angular FOV and spot size, (b) optical entrance aperture, (c) pixel size, and (d) viewing zenith angle. These will be optimized in relation to: (a) The trigger scheme, (b) a read-out multiplexing scheme, (c) single photoelectron counting vs. integration, (d) a calibration system and (e) an atmospheric monitor design.
US Proposed Contribution Theory Develop a top-down type phenomenology, using cutting edge particle physics tools developed at Vanderbilt and UCLA. Theoretical analyses and computer simulation of the acceleration processes in the astronomical sites are planned in the EUSO for maximizing the science return of the proposed mission. U of T, UAH, and UCLA participants will undertake this task. When large-scale computation is needed, our team, lead by U of T, will collaborate with computational members of the new NSF Physics Frontier Center (FOCUS) awarded to U of T and U. Michigan.
US Proposed Contribution Simulations The U.S. contribution will have the following comprehensive elements: (1)The ability to accurately simulate air showers. John Linsley (U. New Mexico), serving as a consultant for this investigation, will provide expertise in building this foundation. (2)The coding of the many theoretical models that seek to explain the CR flux in the EECR energy region in order to calculate the fluxes of protons, nuclei, gamma rays, neutrinos, LSP’s etc. (3)Modeling of the generation of fluorescence light, including the pressure, temperature, and wavelength dependence. (4)The optical design simulations discussed above will be used here also. (5)The modeling of the electronic readout, electronic noise, event trigger, and the study of radiation damage to the electronics have to be accomplished. Vanderbilt University, MSFC, UCLA, and UAH provide these simulations in cooperation with EUSO’s European and Japanese simulation task force teams.
US Proposed Contribution Data Analysis In conjunction with the UCLA team at CERN and MSFC, we plan to work closely with the European EUSO team to develop the U.S. data analysis system. The U.S. group will work closely with the Palermo and CERN teams to develop this program. Simulation events will be processed by the program to test our ability to accurately reconstruct parameters. These in turn will be made available to the EUSO team as well as the U.S. team so that physics analysis can be timely carried out. During turn on and initial payload checkout, the EUSO instrument will be controlled and the quick-look data will be analyzed in the Space Station Operations Center at Marshall. Marshall collaborators will host the European ground segment team and work with them during this crucial initial period.
US Proposed Contribution Electronics Consultations The U.S. team will consult with our European collaborators to search for an improved trigger scheme that makes more complete use of the available information. This may result in more flexible data capture and a robust ability to reprogram the trigger through the life of the mission. The improved scheme will require the development of a digital read-out chip that would be developed in Europe. These consultations will be lead by our team members from Space Science Laboratory at the Univ. of California at Berkeley who have immense experience in the development of state-of-the-art trigger systems. Focal Plane Consultations The proposed contribution includes consultations on the EUSO focal plane array led by the photon detector experts at UCLA. The U.S. team will consult on the following: (1) The optical coupler design and mechanical testing, (2) the mounting of the optical filters provided by the U.S. team on the PMT UV-glass window, (3) the testing of flat panel and multi-anode microchannel plate tube alternatives, and (4) thermal, vacuum, and temporal testing of the photon detectors.
Phase A Studies • Develop a Concept Study Report (Required) • Trade Studies • Lens Material • Lens Design • Lens Manufacturing Techniques • EUSO Tilt Mode • Ground-based calibration source • Manufacturing Tests • Produce replicated segments utilizing RIKEN molds • Produce central 1.5m segment using direct diamond turning • Preliminary Optical System (OS) Mechanical and Thermal Analysis • Preliminary OS to EUSO Interface Control Document