Speakers
Carlos Soncco
(CONIDA)
Luis Otiniano
(CONIDA)
Description
The Astrophysics Direction of CONIDA (Comisión Nacional de Investigación y Desarrollo Aeroespacial) is building Water Cherenkov Detectors (WCDs) as a member of the LAGO project[1]. The aim of the LAGO project is detecting the high-energy component of Gamma Rays Bursts (GRBs). The GRBs are a sudden flow of photons lasting several seconds, occur with an average of a few diaries, with a higher energy spectrum than hard x-rays (1 MeV). They come from other galaxies, if the duration of the GRBs is less than two seconds is a short GRB, if greater than two seconds is a long one. The flux at high energies above 100 GeV is poorly understood due to the difficulty of operate large detectors in satellites[4].
Over 10 GeV a gamma particles generates a decay cascade in their interaction with the atmosphere, these showers are quickly absorved, however positioning detector arrays in high altitude (over 4000 m.a.s.l.) detection possible[3]. The composition of the secondary particles generated by a primary gamma is about 90% of gamma, electron 9% and 1% of other particles. Cherenkov tanks detected gamma via its interaction with Water[2].
Simultaneously, we are working on a Monte Carlo simulation of the water Cherenkov detector to optimize the detection of gamma with (10MeV - 10GeV) entering this. The simulation propagates gammas entering a cylindrical tank of water with its photomultiplier located at the top center central. The relevants electromagnetic processes have been considered (Mean Free Path,Compton effect, pair creation, Ionization Losses, and production and propagation of Cherenkov photons) these equations were obtained from the PDG[5].
The response of the PMT was simulated taking into account the characteristics of the data sheet: quantum efficiency, transit time and the single-electron spectrum. Many parameters must be considered in this simulation, such as the size of the tank, inner surface characteristics and optical properties of the water contained in the tank.
The objective of the simulation is to obtain the optimum size for the manufacture of tanks Cherenkov considering competition between increased detection area and decreasing the size of the signal due to the increased travel of photons inside the tank before hitting the PMT. Cherenkov photons are emitted in a cone shape, the Cherenkov photons are emitted in a cone shape inside the tank, the photons that reach the interior walls are scattered until they reach the PMT, some photons are absorbed by interactions with the environment and the surface of the tank.
The simulation obtained output pulses of the PMT, which are created when a gamma traverses the tank. The load variation of the pulses of the PMT is analized, varying the parameters of the tank dimensions and quality of water.
REFERENCES
[1] X. Bertou et-al, PROCEEDING OF THE 31st ICRC, LODZ 2009 [arXiv:0906.0816]
[2] H. Salazar et-al, PROCEEDING OF THE 31st ICRC, LODZ 2009 [arXiv:0906.0814]
[3] A. De Castro et-al, PROCEEDING OF THE 31st ICRC, LODZ 2009 [arXiv:0906.0820]
[4] P. Meszaros, Rept. Prog. Phys. 69 (2006) 2259 [arXiv:astro-ph/0605208]
[5] PDG [http://pdg.lbl.gov]
Primary authors
Carlos Soncco
(CONIDA)
Luis Otiniano
(CONIDA)
Co-authors
Edith Tueros
(CONIDA)
Mrs
Walter Guevara
(CONIDA)
