Glow Experiment Outline Brandon Hanold

Outline 1.Glow Description 2.Experiment Design 3.Acquisition Loop Variables and Keywords 4.Reduction Results 5.Reduction options 2

Glow Description Glow is defined as integrated charge generated from electrical components of the detector Charge generation from glow can increase the measured “dark current” Glow is often spatially non-uniform Glow can increase when the ROIC is reading out the pixel signal Charge generation sources include: –Heating of analog output buffers –Heating of shift registers –Heating of external temperature sensor on the detector 3

Experiment Design Measurements of glow need to be done in the absence of external photons and thus need to be made in the dark. The experiment setup will be similar to the existing dark current experiment Glow can come from a few different sources, this requires different experiments to determine the glow source and quantity. Amplifier glow from readout amplifiers are a point source generation and will appear non uniform. This means the signal integrated in a dark exposure will be greater in pixels closer to the amplifier (typically around the outer edge of the detector). For this, spatial analysis of dark signal integration is required. Amplifier and shift register glow can be a function of reading out the detector. This means there will be a predictable increase in signal generation every time the detector is read out. For this, analysis of dark signal integration versus number of non-destructive “up-the-ramp” reads is required. Glow is caused by heating of electrical components and is thus dependent on the detector temperature. For this, analysis of dark signal versus temperature is required. Shift register glow can increase with readout speed due to an increase in power consumption. For this, analysis of dark signal integration vs readout speed is required. 4

Acquisition Loop Variables and Keywords Loop Variables: –Temperature –Readout cadence –Readout speed Keyword Input: –Parameter file –Skip temperature –Skip initialization 5

Reduction Results Glow signal integration should be calculated by subtracting the dark current. This requires subtracting data of identical exposure times but different loop parameters. The true dark current should be constant but the signal from glow should be variable. Glow signal integration vs pixel location. –Requires subtracting the median/mode signal integration from each pixel. Glow signal integration vs readout speed (constant exposure time). –Requires subtracting signal integration in identical exposure times with differing readout speeds. Glow signal integration vs number of read frames (constant exposure time). –Requires subtracting signal integration in identical exposure times with differing number of read frames. –Includes a fit and calculation of charge generation per frame. Glow signal integration vs detector temperature. –Requires measuring glow from results of Glow vs number of read frames –This is then measured at different temperatures to see glow vs detector temperature. –There is a change in detector QE which may need to be considered for this result. 6

Reduction Options Bad pixel mask Region specification 7