By GR² Team from LSU LaACES

Science Background Cosmic rays are high energy particles hitting the Earth’s atmosphere Cosmic rays are high energy particles hitting the Earth’s atmosphere The initial particle breaks into a multitude of different particles The initial particle breaks into a multitude of different particles We’re interested in the gamma rays that result from this shower We’re interested in the gamma rays that result from this shower

Science Background, continued Lead-shielded GM tube specialized for detecting gamma radiation Lead-shielded GM tube specialized for detecting gamma radiation Gamma radiation accounts for about one-third of the cosmic ray count Gamma radiation accounts for about one-third of the cosmic ray count

Mission Goals To measure the flux of cosmic radiation (excluding gamma rays) as a function of altitude To measure the flux of cosmic radiation (excluding gamma rays) as a function of altitude To measure the flux of overall radiation as a function of altitude To measure the flux of overall radiation as a function of altitude To determine the flux of gamma radiation versus altitude To determine the flux of gamma radiation versus altitude To determine the ratio of gamma rays to overall flux as a function of altitude To determine the ratio of gamma rays to overall flux as a function of altitude

Payload Design Flight control unit: BalloonSAT® Flight control unit: BalloonSAT® Power source: three 3.6V AA lithium batteries Power source: three 3.6V AA lithium batteries Geiger Müller (GM) tube to measure cosmic ray count Geiger Müller (GM) tube to measure cosmic ray count Lead-shielded GM tube to determine gamma ray count Lead-shielded GM tube to determine gamma ray count Insulation and padding for structure Insulation and padding for structure

System Design Balloon to payload interface: straws and strings Balloon to payload interface: straws and strings Batteries power GM tube boards & BalloonSAT® Batteries power GM tube boards & BalloonSAT® GM tube boards connect to pins P2 (shielded) and P6 (unshielded) GM tube boards connect to pins P2 (shielded) and P6 (unshielded)

Electrical Design Powered by three 3.6V AA lithium batteries Powered by three 3.6V AA lithium batteries BalloonSAT® is the flight control unit BalloonSAT® is the flight control unit Geiger-Müller tubes connect to the FCU via pads P2 and P6 Geiger-Müller tubes connect to the FCU via pads P2 and P6 Fuse rated to ensure safe operation Fuse rated to ensure safe operation

Thermal Design Thermal tests were conducted with various Fom-Cor® set-ups and polystyrene Thermal tests were conducted with various Fom-Cor® set-ups and polystyrene Polystyrene was chosen since it is both insulating and lightweight Polystyrene was chosen since it is both insulating and lightweight Recycled blown-in insulation is added Recycled blown-in insulation is added Reflective tape outside Reflective tape outside

Mechanical Design Lead thickness is 0.6cm to detect about 2/3 of the gamma rays Lead thickness is 0.6cm to detect about 2/3 of the gamma rays Sheets of lead form a partial cylinder shield around the GM tube Sheets of lead form a partial cylinder shield around the GM tube Total weight: 615g Total weight: 615g

Mechanical Design, cont. Top view with vertical insert Top view with vertical insert Recycled blown-in insulation added in open spaces (in plastic baggies) Recycled blown-in insulation added in open spaces (in plastic baggies)

Mechanical Design, cont. Top view, cont. Top view, cont. Side view Side view

Software Geiger mode Geiger mode 256Kb memory chip 256Kb memory chip Reset Basic Stamp program Reset Basic Stamp program Data acquisition program: Data acquisition program: time is set to standard time (Greenwich) to synchronize with altitude data time is set to standard time (Greenwich) to synchronize with altitude data sampling intervals (each 18.1 seconds per interval) sampling intervals (each 18.1 seconds per interval) timestamp to correlate with altitude timestamp to correlate with altitude

Software, cont. Data Retrieval: Data Retrieval: certain steps need to be taken to get the raw data into Excel certain steps need to be taken to get the raw data into Excel data for each tube is organized into four columns data for each tube is organized into four columns Program to correlate counts with altitude Program to correlate counts with altitude Filtering of data: Filtering of data: organization of Excel spreadsheet organization of Excel spreadsheet averaging three consecutive counts to yield an average count per interval averaging three consecutive counts to yield an average count per interval

Temperature Test Confirm the power source could last in upper atmosphere temperatures Confirm the power source could last in upper atmosphere temperatures Confirm that there is no dependence of the measurement on temperature Confirm that there is no dependence of the measurement on temperature Payload passed the test Payload passed the test was working when we took it out of the dry ice chamber was working when we took it out of the dry ice chamber data showed no dependency on the cold temperatures data showed no dependency on the cold temperatures

Pressure Test Because our vacuum source was not operational, a pressure test was impossible Because our vacuum source was not operational, a pressure test was impossible We verified that each material would not “blow up” in the low pressure environment We verified that each material would not “blow up” in the low pressure environment We determined from past flights using the same materials that we would not encounter any issues We determined from past flights using the same materials that we would not encounter any issues

Shock Test The payload was dropped from a height of 10 feet to simulate the force felt upon landing because the nominal descent rate is approx. 20 feet/sec. The payload was dropped from a height of 10 feet to simulate the force felt upon landing because the nominal descent rate is approx. 20 feet/sec. The drop moved the switches on the GM tubes, so we put electrical tape on the switches to hold them in place. The drop moved the switches on the GM tubes, so we put electrical tape on the switches to hold them in place. Nothing was damaged Nothing was damaged

Acknowledgements CSBF CSBF Dr. Guzik Dr. Guzik Dr. Wefel Dr. Wefel Mr. Giammanco Mr. Giammanco Mr. Ellison Mr. Ellison Dr. Cherry Dr. Cherry Mr. Granger Mr. Granger And their loving families!!! And their loving families!!! NASA NASA