Spot-Projector System for the Measurement of Intra-Pixel Response Young Sam YU Background Pixels on imaging sensors do not have uniform response across pixel area Known intra-pixel sensitivity is important for high photometric precision analysis Goals Build a spot projector capable of producing a spot much smaller than the size of a pixel Validate the spot projector’s capability Measure the intra-pixel response for a HyViSI hybrid CMOS detector Expected Spot Size Diffraction limit = 1.22 λ f/D= 1.22 λ f/# = 0.61 λ/N.A. = 2.78 μm Demagnification = 10X Spot Size = sqrt( (Dia.diffraction limit)2 + (Demagnification of Image)2) 5.7 μm 1 μm 10 μm 1 mm 10 mm (Incl. Diffraction) (no. Diffraction) Pinhole size Spot-projector Light guide Neutral filter Diffuser Pinhole Extension Tube Linear Stages Micro-objective lens Infinitube lens CCD Figure 1. Top: Schematic diagram of optical Components in Spot-projector with Ray Tracing (Red). Bottom: Setup of Spot-Projector systems. Result Figure 2. Image of 10 mm pinhole with 10X demagnification. Blue lines represent the radius of the image. Left: Imaging of 10 mm pinhole. Right: Plot of intensity profile from selected radius (Blue region). Red line is at FWHM (59.5 pixels, 9 μm/pix). FWHM is 119 pixels and corresponds 1 mm image size. It is good match to the expected spot size. Summary Demonstrated that our Spot-projector is successfully working (Fig. 2) as expected . Future Work Measure the point spread function of the Spot-Projector using the Knife-edge technique. Measure the Intra-Pixel Response of a HyViSI Hybrid CMOS image sensor. This system will also be used to test the guiding detectors for the Large Synoptic Survey Telescope (LSST). Spot-projector properties Able to produce a spot as small as 5.7 µm to as large as 1 mm. Mounted on a three axis stage giving it the capability to run automated scan sequences across many pixels. Connected to a monochromator allowing us to control the wavelength of light.