Reflective system is a possible solution Reflectivity follow
Fresnel Equation ! Only very small incidence angles can contribute
Only the upper edge of the paraboloid relevant
Slide 7
Parabolic mirror is good for focusing Additional hyperbolic
mirror create an image Wolter Type I Telescope: Primary parabolic
reflector Secondary hyperbolic reflector (small angles) Several
concentric (nested) mirrors increase collecting area Chandra
setup
Slide 8
Spectroscopy The ability of recognize the photon wavelength A
spectrum worth a thousand pictures First spectra achieved by a
proportional detector Gas chamber Output signal prop to photon
energy Low energy resolution
Slide 9
Diffraction Grating
Slide 10
Slide 11
Detection Gas Chamber proportional detector Gas particle went
through photo-ionization The ion is accelerated by the voltage
between anode to cathode Collisions generate more ions which
arrives to the cathode The detected current is proportional to the
photon energy Scintillation proportional detector A solid state
crystal is ionized by a photon The energy transfer into impurities
in the crystal by electron-hole pairs The recombination emit light
in the UV The amount of light is proportional to photon energy
Slide 12
Detection
Slide 13
Semi-Conductor MicroCalorimeter Array of silicon pixel at ~0.1K
Single photon energy is transformed into heat through phonons
Resistance changed fast with temperature (Thermistor)
Slide 14
Detection SuperConducting MicroCalorimeter SuperConducting thin
layer array (at ~1mK) Single photon energy is transformed into heat
The phase transition into a conducting material is detected
Temperature sensitivity is at microKelvin Energy resolution is up
to 2.5 eV (@0.3-7KeV) 300X300micron pixel size (smaller has better
spectral resolution)