TAREAS DE EDUCACIÓN Y DIVULGACIÓN DEL OBSERVATORIO PIERRE AUGER Rebeca López, Preparatoria Emiliano Zapata - BUAP, Objetivo: despertar el interés del público para la comprensión del proyecto, además de la divulgación sobre física básica, astrofísica y algunas otras áreas de la ciencia. Task Leader: Gregory Snow. Argentina: Beatriz García. México:, Rebeca López, Luis Villaseñor y Arnulfo Zepeda. También participan otros miembros de la colaboración como: James Cronin, Alan Watson, etc. Rebeca López R. RESUMEN Rebeca López, Escuela Preparatoria “Emiliano Zapata” BUAP, Puebla, Pue. La Colaboración Internacional del Observatorio “Pierre Auger” tiene como una de sus actividades importantes la divulgación de su objetivo, con la finalidad de despertar el interés del público en él y en algunas áreas de la ciencia básica tales como la física, la astronomía y la astrofísica. México ha contribuido con diversas actividades realizadas en el país y fuera de él. En este trabajo se da a conocer parte de las actividades de educación desarrolladas y las experiencias adquiridas. Estas consisten en dar información global sobre el observatorio, a diversas audiencias, por medio de pláticas, talleres, etc. Se han impartido talleres sobre metodología en enseñanza de la física para profesores en las Cuidades de Malargue y General Alvear de la provincia de Mendoza, Argentina. Además hemos realizado talleres de física a nivel preescolar para despertar el interés por la ciencia desde los primeros años de la vida. Con el fin de que la participación de los países colaboradores en este proyecto sea más organizada actualmente se realizan foros con investigadores del Observatorio y docentes de Argentina. Con esto deseamos que exista una comunicación más estrecha entre investigadores, estudiantes del área, y el público en general. Material referente al observatorio y a las tareas de divulgación: EL MUSEO Eureka en Mendoza Argentina abre sus puertas a la colaboración y desde noviembre del 2003 se cuenta con una sala para el observatorio. Se realizó foro con docentes de la región de Mendoza para que el trabajo de educación y divulgación sea de acuerdo a sus necesidades. El trabajo con los niños a sido la tarea que más se ha desarrollado. Se han organizado talleres, pláticas, visitas, pláticas directas con científicos, etc. Con los docentes se han impartido talleres, pláticas, foros, etc. México a contado en este aspecto con la participación de la cónsul honoraria Mendoza, Arg. Se dan pláticas al público en general y se participa con la población de Malargüe en sus actividades, como el desfile para festejos de su fundación

R. López **, L. Villaseñor*** and A. Zepeda*BUAP, Puebla, **UMSNH, Morelia, Cinvestav, DF Abstract. The physics of cosmic rays was intensively developed during the last century. The subject of ultra high energy cosmic rays has received special attention during the last decade partly due to the controversy between the results of the HiRes and AGASA observatories and the puzzle caused by super-GZK observed events. In this article we review the subject of cosmic rays, first from a historical point of view, then we give examples of methods of measuring cosmic ray properties. INTRODUCTIONIn 1896 the French physicist Henri Becquerel announced the discovery of radioactivity. This phenomenon gave physicists a powerful instrument, a source of high energy projectiles with the help of which experimentalists could probe the structure of the atom and in particular allowed Rutherford to discover the nucleus a decade later. At that time physicists noticed that electroscopes discharge slowly even in the absence of radioactive materials. This residual discharge could not be attributed to charge leakage. A background radiation was conspicuously present. To study the source of this background, several physicists made measurements of radiation levels at different altitudes with refined electroscopes. This puzzle motivated Austrian physicist Victor. F. Hess to make several balloon ascents that culminated in his memorable ascent in 1912 in which he found that the level A key measuring instrument at that time was the "electroscope" whose main part was a system of two gold leaves hanging from a metal road through which they could be electrically charged. The leaves would spontaneously discharge in the presence of radioactive materials. The rate of discharge of an electroscope was used as a measure of the level of radiation. The electroscope thus became a standard instrument for studying radiation and radioactive materials in the first decades of the 20th. Century. of ionizing radiation increased with altitude from 1000 meters up to the maximum height he reached of more than 5 km. The experiments of Robert Millikan provided the final evidence of the existence of this radiation and he coined the name "cosmic rays". Hess was awarded the Nobel Prize in 1936 for his discovery of cosmic rays 1932 Carl Anderson discovered by using the newly invented cloud chamber the first sample of antimatter, the positron, which had been predicted by Dirac a few years before. In 1937 Anderson together with Seth Neddermayer discovered the muon in cosmic rays. Anderson was also awarded the 1936 Nobel Price in physics. In 1938 the French physicist Pierre Auger, discovered extensive air showers. These are cascades of subatomic particles initiated when a single high energy cosmic ray collides with the nuclei of an air molecule high in the atmosphere. The energy of the initial cosmic ray is converted into millions of particles, a process allowed by the equivalence of matter and energy (E=mc2). The shower grows as more particles are produced until they have not enough energy to make more particles and the shower decreases as it moves further in the atmosphere. Further studies by other experimental groups have led to the he conclusion that cosmic rays arrive to the Earth uniformly from all directions. At low energy most of these particles are protons but, when the energy increases other nuclei, like He, C, N, O up to nuclei of Fe, are abundantly present. Gamma particles, coming from gamma ray sources, are also considered cosmic rays. In the energy range of eV, cosmic rays arriving at the edge of the Earth's atmosphere have been measured to consist of 50 % protons, 25 % alpha particles, 13 % C/N/O nuclei, < 1 % electrons, and < 0.1 % gammas. The cosmic ray energy spectrum spans 13 decades of energy, starting from a few tens of MeV per particle up to energies greater than 1020 eV. METHODS OF MEASUREMENTS AND OBSERVATORIES. The strong variation of the rate of arrival of cosmic rays to the Earth demands quite different methods of detection according to the domain of energy being studied. For lower energies the rate is sufficiently fast as to allow the use of a relatively low detecting area aboard satellites and high altitude balloons. An example of this type o experiments is provided by ACE and IMAX, respectively. The Advanced Composition Explorer (ACE) spacecraft samples low-energy particles of solar origin and high-energy galactic particles. MAX is a balloon-borne superconducting magnet spectrometer experiment designed to measure the galactic cosmic ray abundances of protons, antiprotons, deuterium, helium-3, and helium-4 in the energy range from ~0.2 to ~3.2 GeV/nucleon. For primaries of medium energy the front of secondary particles produces Chereknov radiation during its travel in the atmosphere. Although the secondary particles do not reach the ground, the air Cherenkov radiation does and it can be detected with ground based Cherenkov detectors, such us CLUE]. The CLUE Experiment is located on the island of La Palma, Canary Islands, Spain. The aim of CLUE is to measure the ratio of matter/antimatter in the cosmic radiation at energies around one TeV. This measurement can help to distinguish different evolution models of the universe. ACE Mission and Spacecraft. The CLUE Experiment The High Resolution Fly's Eye (HiRes) is a project that follows on from Fly's Eye. HiRes has very good sensitivity and resolution.. The faint fluorescence light is detected by arrays of large mirrors equipped with fast photomultiplier cameras. HiRes collects approximately 300 events per year with energies above eV and many more events below this energy. The largest surface array in operation to study extremely high energy cosmic rays was, until the end of 2003, the Akeno Giant Air Shower Array located in Japan. This array covered an area of 100 km 2 and consisted of 111 detectors on the ground (surface detectors) and 27 detectors located below absorbers (muon detectors). In 1993 Agasa detected a very energetic cosmic ray of energy about 2 x eV. This is the second highest energy cosmic ray ever observed AGASA Observatory The Fly's Eye ObservatoryHi Res telescope mirrors The Pierre Auger Observatory is now the largest observatory Ultra High Energy Cosmic Rays