Small High Altitude Gamma Ray Experiment

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SHAGARE is an interdisciplinary project whose goal is to prototype a basic gamma ray sensor for stratospheric measurements with the help of a high altitude balloon.

 

The laboratories involved are:

 

 

Project Wall

 

Author Message
Joël Vallone This wall is open for any communications and suggestions between the project participants
Olivier Girard From Wednesday 22 May, the detector developed at the LPHE was ready. It comprises an Arduino Uno as data acquisition system (code available here: https://wiki.epfl.ch/shagare/documents/final_datalogger.ino). A picture of the detector is available: https://wiki.epfl.ch/shagare/documents/detector1.JPG
Olivier Girard

Collaboration with Météo Suisse for the launching: Météo Suisse's atmospheric probe will be attached to our payload in order to obtain GPS position and the altitude in real time (we only have a SPOT GPS in our detector).

Météo Suisse has a non-commercial simulation programme that enables to estimate the trajectory of the balloon. Hence, we wait for a safe trajectory and for good weather (quite rare during this month...).

Monday 27 May would have been possible (good weather) but the balloon would have ended up in the lake according to the predicted trajectory (https://wiki.epfl.ch/shagare/documents/flight_cancelled5.jpg).

A nice commercial tool to predict balloon trajectories: http://habhub.org/predict/

Olivier Girard

The flight happened finally on Thursday 30 May. The balloon exploded at an altitude of almost 33km and lasted 2h30min. The trajectory can be seen in this figure: https://wiki.epfl.ch/shagare/documents/realityvsprediction2.jpg

The detector could not be recovered on the same day because it landed at the top of a 20 to 30 meter tree. We contacted Vertige-Concept a company in Yverdon specialized in work at a height and waited until the next Monday.

The box contained some water and the batteries had induced electrolysis. Fortunately, the SD card was not damaged. The data revealed a particle flux increasing with the altitude, but not in the expected way. The spectrum shows interesting features certainly due to charged particles. See my report for the analysis (https://wiki.epfl.ch/shagare/documents/report_balloon_OGirard.pdf).

The RAW data taken during the flight as well as some other files that I used to analyse the data or to run the Arduino are available in the section "files".

Olivier Girard

Main results:

Flux of particles between 700 and 2000 keV: https://wiki.epfl.ch/shagare/documents/flight_flux_vs_alt_plateau.png

Flux of particles between 2000 and 2300 keV: https://wiki.epfl.ch/shagare/documents/flight_flux_vs_alt_saturation.png

Spectrum recorded during the whole flight: https://wiki.epfl.ch/shagare/documents/full_energy_spectrum.png

Spectrum recorded above 25km: https://wiki.epfl.ch/shagare/documents/25km_energy_spectrum.png

Joël Vallone A first prototype board for stratospheric balloon experiments is available at the LAP (see document base report). The software is partially coded. Another student will take care of the development in one of the next semesters.