Cosmic Rays...



Cosmic ray are misterious objects, but they are not ghosts. They are produced far away from earth in supernovaes, gamma ray bursters, and many other astrophysical phenomena. They reach earth in their erratic travel through the universe. Quite often we don't know where they are coming from or even what they are. We can speculate on their nature, origin, etc... The majority of cosmic rays are debris from stars - protons, neutrons, and nuclei ranging from alphas to iron. The sketch below shows the general idea.


Download the sketch in pdf format here. Charged particles have a curved trajectory due to the galatic magnetic field. At sea level most of what is left are muons. There are many experiments built and in construction to look for all sort of things. This link will take you to a gazillion links to cosmic ray experiments. In particular very high energy cosmic rays are of interest. The AGASA experiment has been running for some time and has detected one event with an estimated energy of 2x1020 eV. The largest of its kind now under construction is the Pierre Auger Project. This detector is now under construction in Utah and Argentina. Time properties of cosmic rays, coincidences, time between events, rate as function of time, etc... are not as well studied. However a Japanese Group, LAAS has setup 11 sites throughout Japan to do a study of this kind.

Array of detectors, an idea

The general concept behind the detector system is to have widely distributed sites of small detector arrays. Each site will be equipped with a modest array, 5 to N counters, where N depends on the available hardware. Each site will be able to run independently as far as data collection. The minimum number of 5 detectors is to allow for the determination of the shower size, and more importantly the primary particle direction. Each site is to be equipped with a GPS to record the event time. On a daily basis sites will be uploading the collected data to a master site where all the data will be collated and stored. The global data can then be accessed by the participating sites via the internet (WEB) and analysis performed. Different participating sites will contribute maintaining the arrays but more importantly contributing with ideas for data analysis and developing simple hardware.





Suggested reading

The following list is a short collection of papers on the subject. The first paper discusses the setup in Japan. The second is the search for coincidences at far distances. There is another paper on chaos which is worthwhile reading.



Cosmic Ray experiments with high school participation


The NALTA web site has links to other sites - CHICOS, CROP, WALTA, SALTA. The LAAS is does not involve high schools but only small universities.