Temperature Effects on SCD Output

Shawn Rosofsky

February 4, 2016

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Goal

• Analyze SCD data taken from Goddard thermal vacuum test• Determine the amount of the SCD output changes due to a

change in temperature• This analysis will later be used to help determine how often

to take the pedestal run

Temperature Effects on SCD Output Shawn Rosofsky, UMD

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Relevant Parameters

• SCD– SCD1

• Temperature– SCD Ladder Temperature– Refers to ladder 7 unless otherwise

stated

• Input– SCD has 24 ladders of channels with

its own temperature– Within a ladder groups of 16

channels share similar response patterns

– Total 2640 active channels out of a possible 2944 channels

– 2192 with working temperature sensors

• Output– SCD mean pedestal value for each

channel

Temperature Effects on SCD Output Shawn Rosofsky, UMD

SCD1

SCD Ladder2

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Raw Data Output of SCD1

Temperature Effects on SCD Output Shawn Rosofsky, UMD

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Sample from Each Channels Group of SCD1

Temperature Effects on SCD Output Shawn Rosofsky, UMD

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Channel 0 Linear Fit

Temperature Effects on SCD Output Shawn Rosofsky, UMD

Slope: 19.1 ADC Counts/ºC

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Selected Group 1 Fits

Temperature Effects on SCD Output Shawn Rosofsky, UMD

Slope: 19.1 ADC Counts/ºCIntercept: 5058.0 ADC Counts

Slope: 18.7 ADC Counts/ºCIntercept: 5173.0 ADC Counts

Slope: 18.4 ADC Counts/ºCIntercept: 5134.3 ADC Counts

Slope: 19.2 ADC Counts/ºCIntercept: 5018.5 ADC Counts

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Results of Group 1 Fits

• Slope– Mean: 18.6 ADC Counts /ºC– Standard Deviation: 0.3 ADC

Counts /ºC

• Intercept– Mean: 5089.6 ADC Counts – Standard Deviation: 60.5

ADC Counts

• Conclusion: – Groups of channels

characterize an SCD region’s response to temperature shifts

– Output of channels within a group may differ

Temperature Effects on SCD Output Shawn Rosofsky, UMD

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Selected Channels from Various Groups

Temperature Effects on SCD Output Shawn Rosofsky, UMD

Slope: 19.1 ADC Counts/ºCIntercept: 5058.0 ADC Counts

Slope: 21.0 ADC Counts/ºCIntercept: 4782.5 ADC Counts

Slope: 19.6 ADC Counts/ºCIntercept: 4697.7 ADC Counts

Slope: 14.6 ADC Counts/ºCIntercept: 4563.5 ADC Counts

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Histogram of Slopes

Temperature Effects on SCD Output Shawn Rosofsky, UMD

Mean: 17.1 ADC Counts/ºCStandard Deviation: 15.0 ADC Counts/ºC

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Outliers

• All but 9 channels had slopes between 0 and 35 ADC Counts/ºC

• Most of these outliers appeared within this range expect for a large spike in one of the data points – Spike typically appeared

in coldest measurement

Presentation Title Name, UMD

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Histogram of Slopes Excluding Outliers

Temperature Effects on SCD Output Shawn Rosofsky, UMD

Mean: 16.9 ADC Counts/ºCStandard Deviation: 2.6 ADC Counts/ºC

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Results

• Temperature has a significant effect on SCD output– 16.9 ADC Counts/ºC on average (excluding outliers)

• Effect appears linear in nature• Affects different regions of SCD differently• Groups of 16 consecutive channels display very

similar responses to temperature shifts

Temperature Effects on SCD Output Shawn Rosofsky, UMD

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Shortcomings

• Incomplete mapping of SCD channel location– Temperature used may not always be accurate

• Unable to analyze raw pedestal data output– Cannot independently verify means or determine

uncertainty

• Cause of outliers unknown

Temperature Effects on SCD Output Shawn Rosofsky, UMD

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Future Items

• Transient analysis of temperature change in SCD– Typical timescale for temperature shift

• Determine how much of a temperature shift significantly affects our data collection

• Decide how often to run pedestal measurements

Temperature Effects on SCD Output Shawn Rosofsky, UMD

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Cited Images

• 1) Jik Lee. Design, Fabrication and Performance of the Silicon Charge Detector for the ISS-CREAM. The 34th International Cosmic Ray Conference, 30 July- 6 August, 2015. The Hague, The Netherlands.

• 2) Rosemary Thorpe. ISS-CREAM Thermal and Fluid System Design and Analysis. TFAWS 2015 – August 3-7, 2015 – Silver Spring, MD.

Presentation Title Name, UMD