Noise Characterization of the SIDECAR ASIC Readout Chip for SNAP Martin Diaz Stanford Linear Accelerator Center August 14, 2008

Our Expanding Universe The expansion history of the universe can be mapped out The expansion history of the universe can be mapped out What is causing it to accelerate? What is causing it to accelerate?

Dark Energy Believed to be the reason for the accelerating expansion Believed to be the reason for the accelerating expansion Dark energy dominates our universe Dark energy dominates our universe Yet, little is known about it Yet, little is known about it

Dark Energy

SuperNova Acceleration Probe Part of the Joint Dark Energy Mission (JDEM) Part of the Joint Dark Energy Mission (JDEM) Between NASA and DOE Between NASA and DOE

SuperNova Acceleration Probe Weak gravitational lensing Weak gravitational lensing N. Kaiser

SuperNova Acceleration Probe Measure changes in the expansion rate with the help of type Ia supernova Measure changes in the expansion rate with the help of type Ia supernova

Type Ia Supernova No observed Hydrogen No observed Hydrogen Found in spiral and elliptical galaxies Found in spiral and elliptical galaxies Outer stellar layers missing prior to explosion Outer stellar layers missing prior to explosion

Type Ia Supernova Binary System Binary System Matter is transferred Matter is transferred Causes white dwarf to implode Causes white dwarf to implode

Type Ia Supernova Luminosity is from radioactive decay of Cobalt and Nickel into Iron Luminosity is from radioactive decay of Cobalt and Nickel into Iron Same Fuel = Same Luminosity Same Fuel = Same Luminosity Act as “Standard Candles” Act as “Standard Candles”

SuperNova Acceleration Probe SNAP will measure: SNAP will measure: Peak brightness Peak brightness Distance away Distance away Redshift Redshift Expansion factor Expansion factor

SuperNova Acceleration Probe SIDECAR ASIC

SIDECAR System for Image Digitization Enhancement, Control and Retrieval Application Specific Integrated Circuit (ASIC) System for Image Digitization Enhancement, Control and Retrieval Application Specific Integrated Circuit (ASIC) Alternative to discrete electronics Alternative to discrete electronics

SIDECAR Converts Analog signal from image detector to digital signal Converts Analog signal from image detector to digital signal Easily transmitted and stored Easily transmitted and stored

SIDECAR Problem: Reduce noise Problem: Reduce noise Method: Optimization of microcode Method: Optimization of microcode Compare multiple images Compare multiple images Without image sensor Without image sensor

SIDECAR Procedure Procedure Two consecutive images Two consecutive images Take difference in pixel value Take difference in pixel value Collect to form histogram and obtain RMS Collect to form histogram and obtain RMS Results Results

SIDECAR Procedure Procedure After some modification to the Amplifier Reset After some modification to the Amplifier Reset Results Results

SIDECAR Procedure Procedure 100 images 100 images Compare a single pixel Compare a single pixel Results Results

SIDECAR Procedure Procedure 50 images 50 images 256 pixels 256 pixels Results Results

Conclusion After testing the SIDECAR in 32 channel mode After testing the SIDECAR in 32 channel mode Microcode optimization Microcode optimization RMS value as low as 4.8 RMS value as low as 4.8

Future Work Operation under cryogenic temperatures Operation under cryogenic temperatures Integration with Hybrid Visible Silicon Imager (HyViSI) imaging sensor. Integration with Hybrid Visible Silicon Imager (HyViSI) imaging sensor.

Acknowledgements Thank you to my mentor Leonid Sapozhnikov and the rest of the SNAP team. I would also like to thank the Department of Energy and the SULI staff. Thank you to my mentor Leonid Sapozhnikov and the rest of the SNAP team. I would also like to thank the Department of Energy and the SULI staff.

Resources C. Bebek, “The SNAP Space Mission”, Nuclear Instruments and Methods in Physics Research, Vol. 579, Issue 2, pp , M. Loose et al., “The SIDECAR ASIC – Focal Plane Electronics on a Single CHIP”, Cryogenic Optical Systems and Instruments XI, Proc. SPIE Vol. 5904, pp , 2005.