Jenny Carter LXO/MagEX optics and sims October 2007 Optics and Simulations Jenny Carter, Steve Sembay & Andy Read

Jenny Carter LXO/MagEX optics and sims October 2007 Telescope set-up Slumped micro channel plate with detector (CCD) at focal plane Curved focal plane

Jenny Carter LXO/MagEX optics and sims October 2007 Introduction to the MCP or MPO Microchannel plates or micropore optics Matrix of channels – can act as a detector or optic Channel length: ~ 1mm Manufactured using core-cladding process; channel glass and core glass drawn down in stacks, core glass etched away to leave channel matrix. Advantages: light-weight, compact, high effective area Disadvantages: may be flimsy when made very large Channel aspect ratio: length-diameter L/D Different packing and pore shapes available Typical L/Ds: small – 20:1, large – 500:1 Different style slumping possible

Jenny Carter LXO/MagEX optics and sims October 2007 Microchannel plate optics

Jenny Carter LXO/MagEX optics and sims October 2007 Aspects to consider Optics – some features Focal length Point spread function (PSF) Choice of materials, coatings Channel aspect ratio OPTIMISATION OF OPTICS SYSTEM Detector system – Steve’s talk OPTIMISATION OF DETECTOR SYSTEM Combined simulations - eventually OPTIMISATION OF TELESCOPE

Jenny Carter LXO/MagEX optics and sims October 2007 PSF Pyramid structure due to reflections on different walls in the channels Number of reflections function of incident angle and aspect ratio Characteristic cruciform shape

Jenny Carter LXO/MagEX optics and sims October 2007 Dependent on energy, the coating and radius of curvature of the optic Combined with quantum efficiency and filter transmission etc. of the final system, an auxiliary response file can be created Effective area

Jenny Carter LXO/MagEX optics and sims October 2007 Simulations at Leicester so far Based on Robertson and Cravens models Basic plan: use model to determine SWCX flux model spectra to find count rate use count rates to simulate images for different FOVs, solar wind conditions etc.

Jenny Carter LXO/MagEX optics and sims October 2007 Simulation set-up Looked at different FOVs Used effective area curve for another Leicester slumped-MCP project – peak at ~ 13 cm 2 Use Xspec fitting to fake spectra, 0.2 – 2 keV Use adapted XMM-Newton MOS camera response, low-energy resolution improvement: ~ 50 eV 600 eV

Jenny Carter LXO/MagEX optics and sims October 2007 Model basis Snowden et al., HDFN and SWCX, ApJ, 610, 1182, 2004, scale to model LineEnergy (keV) C VI0.37 C VI0.46 O VII0.56 O VIII0.65 O VIII0.81 Ne IX0.91 Mg XI1.34 FOV (deg.)PositionConditionFlux keV s -1 cm -2 9x9CN x20CN x30CN x9CS x20CS x30CS x9ON x20ON x30ON0.370

Jenny Carter LXO/MagEX optics and sims October 2007 Bkg components Background (bkg) components: sky bkg particle-induced bkg lunar bkg Sky bkg model using Snowden et al. components Sky bkg scaled to values in the literature (Lumb et al., A.&A. 389, 2002) Particle-bkg scaled to XMM-Newton MOS Limitations: particle-induced bkg scaling, no temporary/spatial variation of sky bkg, no instrumental lines wabs * (raymond + powerlaw + raymond) + vapec + raymond Sky: MW-halo, local halo, cosmic bkg, local hot bubble

Jenny Carter LXO/MagEX optics and sims October 2007 MagEX Simulations ‘Storm’ Conditions Typical diffuse sky and detector background MCP Optic keV FOV 9x9 deg Lunar background can range from negligible to comparable with the magnetosheath Lunar bkg values taken from Figure 6., original LSSO proposal (azimuthal angle of 0 deg., zenith angle of 90 deg.)

Jenny Carter LXO/MagEX optics and sims October 2007 MagEX Simulations ‘Normal’ Conditions Typical diffuse sky and detector background MCP Optic keV FOV 20x20 deg Pixel size 10 arcmin Longest exposures represent stacking of data at similar sun-moon-earth angles and similar solar conditions 1 ks10 ks 100 ks 1 Ms

Jenny Carter LXO/MagEX optics and sims October ks10 ks 100 ks 1 Ms MagEX Simulations ‘Storm’ Conditions Typical diffuse sky and detector background MCP Optic keV FOV 20x20 deg Pixel size 10 arcmin Longest exposures represent stacking of data at similar sun-moon-earth angles and similar solar conditions

Jenny Carter LXO/MagEX optics and sims October ks10 ks 100 ks 1 Ms MagEX Simulations ‘Storm’ Conditions Typical diffuse sky and detector background MCP Optic keV (Oxygen) FOV 20x20 deg Pixel size 10 arcmin Longest exposures represent stacking of data at similar sun-moon-earth angles and similar solar conditions

Jenny Carter LXO/MagEX optics and sims October 2007 Simulation software for optics- detector system Sequential ray tracing software Developed at Leicester Uses q, like IDL What we can vary: source setup – finite/infinite distance or diffuse (uniform random distribution over a hemisphere), number of rays optics setup – radius of curvature, channel aspect ratio, surface roughness, component materials detector setup – detector type (whether planar, spherical etc.), radius of curvature other aspects – surface qualities, supporting structures etc. Want to optimise PSF and effective area for a diffuse source Source rays OpticDetector

Jenny Carter LXO/MagEX optics and sims October 2007 Simulation software for experiment in lunar orbit Satellite tool kit (STK), widely used Images viewpoints, pointings, FOVs, elevations of instruments ….. movies Output wide range of possible output parameters. For example orbital info so can add to model of magnetosheath emission take info over time to model run in conjunction with temperature simulations, illumination over time etc.

Jenny Carter LXO/MagEX optics and sims October 2007 Plans Run sequential ray tracing for various telescope and detector configurations Concentrate on various aspect ratios for diffuse emission Use Sat Tool Kit software to simulate FOV from the Moon over different mission lifetimes, observing times and lunar locations and phase of lunar night Address various issues from the current simulations: particle background contributions, lunar contributions, more detailed effective area consideration, proper vignetting consideration Study possibilities of curved or side-buttable CCDs to be placed at the detector plane

Jenny Carter LXO/MagEX optics and sims October 2007 STK examples Equatorial, 20x20 and 30x30 degrees Polar (north), 20x20 and 30x30 degrees Polar (south), 20x20 and 30x30 degrees – with ROSAT bright source catalogue > 10 ct/s added to sims Blue grid – Earth inertial frame Yellow vector – Sun pointing Purple sphere – Earth centred, 10 Earth radii Green rectangle - FOV

Jenny Carter LXO/MagEX optics and sims October 2007