Question 4 (25 points) The Vera C. Rubin Observatory will have the largest CCD camera of every telescope, enabling wide-

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Question 4 25 Points The Vera C Rubin Observatory Will Have The Largest Ccd Camera Of Every Telescope Enabling Wide 1 (414.65 KiB) Viewed 24 times

Question 4 (25 points) The Vera C. Rubin Observatory will have the largest CCD camera of every telescope, enabling wide-field observations of space. The camera was recently tested in its cryostat for cooling the sensor array. A. If astronomers want to observe a star with a surface temperature of 3300 K, at which wavelength can they expect maximum radiative emission, assuming the star behaves like a black body radiator? (6 points) B. If they use a spectral filter that selects a narrow wavelength range around the maximum emission wavelength, how many photons will arrive at a detector per second if the illumination power is 1.5x10-12 W? (6 points) C. The CCD camera is made of an array of silicon photodetectors in which electrons in the valence band are excited into the conduction band by the absorbed photons. How large is the remaining kinetic energy of the photoelectrons, assuming a band gap of 1.12 eV for silicon? (6 points) D. Unfortunately, the kinetic energy of the photoelectrons will be converted into thermal energy within a few femtoseconds. How much heating power in W will the photoelectrons generate? Will this have a significant impact on the cooling system, which is designed to deal with a 400 W heat load? (7 points)