Transcript maxim
Webster Cash University of Colorado MAXIM Galaxies Clusters of Galaxies 22 Star Clusters 20 SNR 18 Log Diameter (cm) AGN Jets 16 AGN BLR Sne 14 Interacting Binaries 12 AGN Event Horizons XRB Orbits Stellar Coronae 10 GRB Afterglow CV XRB Disks 8 6 NS Disks 0 1 2 3 4 5 6 Log Distance (pc) 7 8 9 10 Capella 0.0001” Capella 0.000001” AR Lac Simulation @ 100mas AGN Accretion Disk Simulations @ 0.1mas Courtesy of Phil Armitage, U. Colorado and C. Reynolds, U. Maryland Need Resolution and Signal If we are going to do this, we need to support two basic capabilities: • Signal • Resolution X-ray Sources Are Super Bright Example: Mass Transfer Binary 1037ergs/s from 109cm object That is ~10,000L from 10-4A = 108 B where B is the solar brightness in ergs/cm2/s/steradian Brightness is a conserved quantity and is the measure of visibility for a resolved object Note: Optically thin x-ray sources can have very low brightness and are inappropriate targets for interferometry. Same is true in all parts of spectrum! Artist’s impression of Cyg X-1 (NASA) My Impression Status of X-ray Optics • Modest Resolution – 0.5 arcsec telescopes – 0.5 micron microscopes • Severe Scatter Problem – Mid-Frequency Ripple • Extreme Cost – Millions of Dollars Each – Years to Fabricate Pathlength Tolerance Analysis at Grazing Incidence A1 B1 sin B2 B1cos2 A2 OPD B1 B 2 B1 A1 & A2 in Phase Here B2 1 cos2 2 sin sin If OPD to be < /10 then 20 sin C d Baseline S2 S1 d focal 20 sin cos 20 sin 2 A Simple X-ray Interferometer Flats Detector Wavefront Interference =s (where s is fringe spacing) s d/L L s d Optics Each Mirror Was Adjustable From Outside Vacuum System was covered by thermal shroud X-ray Fringes 0.5keV Gendreau, October 2002 1.25keV Cash et al March 1999 Flats Held in Phase Sample Many Frequencies As More Flats Are Used Pattern Approaches Image 2 12 4 8 16 32 Periscope Configuration Keeps beam pointed in constant direction like thin lens To focus Parallel to Source Direction Reduces Sensitivity to Baseline Each Periscope in the array is held to /20sin 10m Periscopes allow for delay in each channel. Can sample full UV plane. focus Periscope Requirements • Even Number of Reflections With odd number of reflections, beam direction shifts with mirror tilt With even number, the mirrors compensate and beam travels in same direction. Phase Shift h Path Delay = h sin so h < /10 for phase stability if h~1cm then < 10-8 (2 milli-arcsec) This can be done, but it’s not easy. Phase Delay d2 d1 P d1 (cos cos sec22 21 sin cot 2 sin sec(22 21 )cot 1 cos 21 (cot 1 cot 2 ) d 2 (cos 2 cos 2 sec2 4 23 sin 2 cot 4 sin 2 sec(2 4 23 )cot 3 cos 23 (cot 3 cot 4 ) There are Solutions This solution can be direction and phase invariant Dennis Gallagher has verified this by raytrace! Pointing can wander arcseconds, even arcminutes, and beam holds fixed! Array Pointing • 4 mirror periscopes solve problem of mirror stability • But what about array pointing? • Doesn’t the array have to be stable to 1mas if we are to image to 1mas? Thin Lens Behavior As a thin lens wobbles, the image in space does not move Position on the detector changes only because the detector moves Formation Flying If detector is on a separate craft, then a wobble in the lens has no effect on the image. But motion of detector relative to Line of Sight (red) does! Much easier than stabilizing array. Still the toughest nut for full Maxim. Variety of solutions under development. Mirror FEM Mirror Face Mirror Back 3pt Ti Flexure Mount Optic w/Face Sheet Removed Mirror Analysis Summary Analysis Goal/Req. Result Comments o min surface deformation PtoV=6.2nm, RMS=1.2nm o min surface deformation PtoV=3.2nm, RMS=0.6nm Gradient across mirror surface o min surface deformation PtoV=3.1nm, RMS=0.6nm Gradient across mirror surface o min surface deformation FF > 100 Hz Mount Stress < Yield Low Mirror Stress Gradient through mirror thickness Mirror on flexures, but not entire mount 20g Y Loading 20g Y Loading 1 c Bulk Temp Load 1 c X Gradient 1 c Y Gradient 1 c Z Gradient Fixed Base Dynamics 20g Quasi Static Load 20g Quasi Static Load 1cZ Mirror Deformations (mm) PtoV=17.0nm, RMS=3.8nm FF=278 Hz 35 MPa maximum 7.6MPa maximum 20gY Mirror Back Stresses (MPa) Mirror First Mode = 278 Hz MAXIM Position Tolerances =1nm, F=20,000km, D=1km, m=30cm, =1deg, h=1mm DOF X Y Z 20 3 sin( ) cos( ) m sin( ) 10 3 Z-rot (roll) cos( 2 ) 20 3 sin 2 ( ) X-rot (yaw) Y-rot (pitch) Periscope Equation Mirror Equation 5D m sin( ) 10 4F2 5D 2 sin( ) 5 3 2 2 m sin 1 3 10m sin 10 F 1 3 sin F m sin 10 m sin 10 F 2 2 sin( ) 15 20h 2F 5D 2 Mirror Tolerance Periscope Tolerance ±1.7nm ±4mm ±0.3mm ± 0.5mm ±94.7nm ±0.32m ±6.9 arcmin ± 7.8 arcmin ±2.3 marcsec ± 10 arcsec ±0.13 arcsec ±18.5 arcsec Optical Bench FEM “Daughter” Benches Main Bench Flexure Fixed Mount Simplified Optics Mounts Periscope Assembly Assy. Kinematic Mounts (3) Entrance Aperture (Thermal Collimator) Shutter Mechanism (one for each aperture) Launch Configuration Layout Delta IV ø5m x L14.3m 24 Free Flyer Satellites (4 Apertures ea.) 1 Hub Satellite (12 Apertures) 1 Detector Satellite Ø4.75m Aperture Locations (central area) 18 13 14 12 7 6 1 26 5 4 11 10 17 16 8 2 3 9 15 On the left is the probability distribution function for two sources in the same field of view. The central source has an energy half that of the source that is displaced to the lower left. The image on the right shows 9000 total events for this system with the lower energy source having twice the intensity of the higher energy source. Even though the higher energy source is in the first maxima of the other, the two can still be easily distinguished. Stars Simulation with Interferometer Sun with SOHO The Beyond Einstein Program optical imaging Hubble LISA Dark Energy Probe LIGO dark energy physics space interferometry, gravitational wave detection gravitational wave detectors space interferometry MAP microwave background detection Inflation Probe Big Bang Observer dark matter physics Constellation-X Chandra black hole physics Black hole imager x-ray imaging hard x-ray detectors Swift Science and Technology Precursors Black Hole Survey Probe black hole census Bottom Line • Maxim can be built in an affordable way • Achieving 0.1mas can be done with modest control in free-flying • Full black hole imaging for under $900M • Maxim is in the planning • NRA for “Vision Mission Studies” coming out this week.