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## Gain Curves

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**Gain Curves**Jason for the SB Crew June 5, 2007**Raw 55Fe Spectra**• Start with 55Fe spectrum from a MCA. • Fit peak to gaussian. • Calibration from a pulser turns channels into electrons. • Mean of gaussian corresponds to signal from 109 electrons (in CF4).**Raw Curves**• Procedure: • 14 hour gain saturation curve • to fully charge up the stack • waited ~2 hours with voltage on • to verify stable gain • measured gain as a function of dV • source rate: ~100 Hz**Raw Curves**• Procedure: • 14 hour gain saturation curve • to fully charge up the stack • waited ~2 hours with voltage on • to verify stable gain • measured gain as a function of dV • source rate: ~100 Hz**P/T Corrections**• sealed volume in gain test box allows for easy P/T mapping. • in very good agreement with WIS. • Therefore, gain can be adjusted for P/T variations…**P/T Corrected Curves**• Procedure: • 14 hour gain saturation curve • to fully charge up the stack • waited ~2 hours with voltage on • to verify stable gain • measured gain as a function of dV • corrected for P/T !! • source rate: ~100 Hz**P/T Corrected Curves**• Procedure: • 14 hour gain saturation curve • to fully charge up the stack • waited ~2 hours with voltage on • to verify stable gain • measured gain as a function of dV • corrected for P/T !! • source rate: ~100 Hz**Gain Saturation Curve**• Sample gain every two minutes for 14 hours. • Fit saturation curve to saturating exponential. • Gives the ability to extrapolate gain.**Completely Corrected Curves**• Procedure: • 14 hour gain saturation curve • to fully charge up the stack • waited ~2 hours with voltage on • to verify stable gain • measured gain as a function of dV • corrected for P/T !! • use extrapolated saturation curve to correct for time… • SB sees a factor of ~2 • source rate: ~100 Hz**Completely Corrected Curves**• Procedure: • 14 hour gain saturation curve • to fully charge up the stack • waited ~2 hours with voltage on • to verify stable gain • measured gain as a function of dV • corrected for P/T !! • use extrapolated saturation curve to correct for time… • SB sees a factor of ~2 • source rate: ~100 Hz**Completely Corrected Curves**• Procedure: • 14 hour gain saturation curve • to fully charge up the stack • waited ~2 hours with voltage on • to verify stable gain • measured gain as a function of dV • corrected for P/T !! • use extrapolated saturation curve to correct for time… • source rate: ~100 Hz **note** the WIS data is from two different stacks… a gem was exchanged. --maybe not comparable.