BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Investigation of atmosphere thickness on EAS events by an array of
  particle detectors and CORSIKA simulations.
DTSTART;VALUE=DATE-TIME:20070704T194500Z
DTEND;VALUE=DATE-TIME:20070704T194500Z
DTSTAMP;VALUE=DATE-TIME:20260607T173554Z
UID:indico-contribution-266@cern.ch
DESCRIPTION:Speakers: Dr. KHAKIAN\, Mehdi (Physics Dept.\, Sharif Univ. of
  Tech.\, 11365-9161\, Tehran\, Iran.)\nActually until the shower maximum t
 he effect of the atmosphere is: 'an \nenvironment for extension of EAS eve
 nts'\, but after it the 'absobtion effect of \nthe atmosphere' will be dom
 inant. Since the shower maximum for ~100 TeV is \n~550 gr/cm^2(~5000m a.s.
 l)\, and we are always after it (1200m a.s.l) specially \nfor higher zenit
 h angle events. So actually in the energy and the site we have \nto concen
 trate more on the absorbtion effect.\nTherefore for the investigation we l
 ogged about 400\,000 EAS events by an \narray of particle detectors in a s
 quare 6m*6m. These cylindrical (r=35cm\, \nh=120cm) detectors contain pure
  water and a face sinked PMT inside the water \nfor detection of emitted C
 erencov light from passed charged particles through\nthe water.\nWe calcul
 ated the local coordinates of (z\,\\phi) of each event. The z\ndistributio
 n of the logged events is dN=\\sin(z)\\cos^n(z)dz with\nn=6.03. It seems t
 hat the decreasing distribution is due to the\natmosphere thickness\, so f
 or better investigations of the effect we\ncalculated the time differences
  between each two to six following events\nand we obtained the rate=(29.33
 +-0.14 sec)^-1. With the rate and\nHillass formula (Gaisser 1990) we obtai
 ned the energy threshold\nE_{th}=52 TeV. From 70\,000 CORSIKA simulations 
 of our experiment we\nobtained it 58 TeV. Then we fitted our simulated EAS
  events (50TeV to\n5PeV) on the characteristics of our detectors and our a
 rray\, and we\ncalculated a probability distribution for different zenith 
 angles which is\nin agreement with z distribution of our experiment. Also 
 we drew the\ndistribution of number of the secondary particles vs. z and t
 he\ndistribution of number of simulated events vs. secondary particles.\nT
 hen we extracted the distribution of the number of simulated events\nvs. z
 . This is a good observable factor to compare with the\nexperiment result.
  Our results show that a good coincidence between\nthe simulated and obser
 ved curves. small differences in different\nzenith angles is from the 'eff
 iciency of our array' which is in the\ninvestigation precess.\n\nhttps://i
 ndico.nucleares.unam.mx/event/4/session/8/contribution/266
LOCATION:Merida\, Mexico Regency (Hyatt)
URL:https://indico.nucleares.unam.mx/event/4/session/8/contribution/266
END:VEVENT
END:VCALENDAR