BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:OBSERVATIONS OF IMPULSIVE NITRATE ENHANCEMENTS ASSOCIATED WITH GRO UND-LEVEL COSMIC RAY EVENTS 1-4 (1942-1949) DTSTART;VALUE=DATE-TIME:20070707T153000Z DTEND;VALUE=DATE-TIME:20070707T154200Z DTSTAMP;VALUE=DATE-TIME:20260914T185716Z UID:indico-contribution-81-0-725@cern.ch DESCRIPTION:Speakers: Dr. SMART\, Don (Emeritus\, Air Force Research Labor atory)\nA direct comparison of impulsive nitrate enhancements observed in multiple \npolar ice cores from both hemispheres is presented for the year s 1940-1950. \nDuring that time period\, four ground-level solar cosmic r ay events (GLEs) were \nrecorded by ionization chambers. We show that lar ge and sudden \nenhancements in the nitrate records from both hemispheres were observed \nwithin weeks of the dates of the GLEs. The observation of impulsive nitrate \nenhancements simultaneously in both hemispheres short ly after a solar proton \nevent is strong evidence in support of a causal connection and argues strongly \nfor rapid gravitational precipitation of atmospheric nitrates.\n\nhttps://indico.nucleares.unam.mx/event/4/session/ 81/contribution/725 LOCATION:Merida\, Mexico Yucatan I (Fiesta Americana) URL:https://indico.nucleares.unam.mx/event/4/session/81/contribution/725 END:VEVENT BEGIN:VEVENT SUMMARY:Detection of gamma-rays from winter thunderclouds along the coast of Japan Sea DTSTART;VALUE=DATE-TIME:20070707T154200Z DTEND;VALUE=DATE-TIME:20070707T155400Z DTSTAMP;VALUE=DATE-TIME:20260914T185716Z UID:indico-contribution-81-0-867@cern.ch DESCRIPTION:Speakers: Mr. ENOTO\, Teruaki (Department of Physics\, Univers ity of Tokyo)\nThe increasing number of reports on the gamma-ray detection from thunder clouds and\nlightenings indicate that charged particles are accelerated by the strong electric fields\nassociated with the thunder phe nomena. In order to search for high-energy radiation\nfrom winter thunder clouds in the Japan sea coast areas\, we have set up an autonomous\nradiat ion detection system at Kashiwasaki\, Niigata prefecture\, Japan. The sys tem\ncomprises several different types of radiation detectors\, including NaI and CsI\nscintillators\, NaI/BGO phoswitch detectors\, and plastic sci ntillators. In addition\,\nsome auxiliary sensors for visible light\, soun d\, and electric field are installed. We\nstarted the observation in Decem ber 2006\, and successfully detected at least one\nsignificant radiation i ncrease associated with a heavy thunder activity on January 7\,\n2007. The event lasted for 100 sec\, preceding a possible thunder strike. The signa ls\nwere detected by all the inorganic scintillators\, but by none of the plastic\nscintillators\, suggesting that the radiation is predominantly en ergetic gamma-rays.\nThe energy spectrum extends up to 10 MeV\, and the si ngal arrival direction is\nconsistent with general sky direction.\n\nhttps ://indico.nucleares.unam.mx/event/4/session/81/contribution/867 LOCATION:Merida\, Mexico Yucatan I (Fiesta Americana) URL:https://indico.nucleares.unam.mx/event/4/session/81/contribution/867 END:VEVENT BEGIN:VEVENT SUMMARY:Variation of C-14 concentrations of single-yr tree rings at the ra pid change in 2600-yrBP DTSTART;VALUE=DATE-TIME:20070707T155400Z DTEND;VALUE=DATE-TIME:20070707T160600Z DTSTAMP;VALUE=DATE-TIME:20260914T185716Z UID:indico-contribution-81-0-240@cern.ch DESCRIPTION:Speakers: Ms. TAKAHASHI\, Yui (Department of Physics Yamagata University)\nC-14 concentrations of single-yr tree rings indicate solar mo dulations of cosmic \nrays such as 11-yr solar cycle. Old tree rings are a powerful tool to detect the \nvariations of cosmic-rays in past time. Fro m C-14 dating\, the calendar age of \nthe Choukai Jindai cedar in Japan (3 9°N) was ranged in from 2757 to 2437 cal \nBP with 320 tree rings. Accord ing to IntCal04 which is the standard \ninternationally recommended radioc arbon calibration data set\, a rapid change \nof the C-14 concentrations i s seen in 50 years in 2650 to 2600 cal BP by \ncalendar year. In order to investigate the structure in detail\, we have \nmeasured the C-14 concentr ations of single-yr tree rings using the Choukai \nJindai cedar during the 50 years\, because the data set of IntCal04 was for 5-\nyear span. The C- 14 of single-yr tree rings have been measured with the highly \naccurate l iquid scintillation counting system with 0.2% accuracy synthesizing a \nla rge quantity of 5.3 g benzene for each alpha cellulose sample produced fro m \ntree rings. The measured C-14 concentrations showed a rapid change wit h the \ndecreasing rate of 0.8% for 2 years. We report the structure of th e C-14 \nvariation.\n\nhttps://indico.nucleares.unam.mx/event/4/session/81 /contribution/240 LOCATION:Merida\, Mexico Yucatan I (Fiesta Americana) URL:https://indico.nucleares.unam.mx/event/4/session/81/contribution/240 END:VEVENT BEGIN:VEVENT SUMMARY:SOLAR PROTON FLUENCE FOR 31 SOLAR CYCLES DERIVED FROM NITRATE ENHA NCEMENTS IN POLAR ICE DTSTART;VALUE=DATE-TIME:20070707T160600Z DTEND;VALUE=DATE-TIME:20070707T161800Z DTSTAMP;VALUE=DATE-TIME:20260914T185716Z UID:indico-contribution-81-0-718@cern.ch DESCRIPTION:Speakers: Dr. SHEA\, Margaret (Emeritus\, Air Force Research L aboratory)\nUsing nitrate enhancements in the polar ice as a proxy for sol ar proton events\, \nwe have determined the proton fluence above 30 MeV fo r 31 solar cycles \nbetween 1610 and 1954 (cycle -12 through cycle 18). O ur results show a wide \nrange of solar proton fluences over these 31 sola r cycles\, from three cycles with \nno significant proton events above 10* *9 protons/cm to a high of 38 x 10**9 \nprotons/cm. In a comparison of th e two cycles with the highest solar proton \nfluence\, we find that cycle 10 was dominated by one major event (the \nCarrington event in 1859) while cycle 13 had 7 major events contributing to the \ntotal fluence. While t he total fluence for most cycles is within a factor of 2 of the \nfluence measured by spacecraft since 1965\, the fluence for cycles 10 and 13 is a \nfactor of 4 greater than present day spacecraft measurements. Until new deep \nice cores are available for both calibration with known fluences a nd for \nverification of the original results\, these derived solar proton fluences over a \nsolar cycle represent the only available values as uppe r limits for space \nexploration experiments.\n\nhttps://indico.nucleares. unam.mx/event/4/session/81/contribution/718 LOCATION:Merida\, Mexico Yucatan I (Fiesta Americana) URL:https://indico.nucleares.unam.mx/event/4/session/81/contribution/718 END:VEVENT BEGIN:VEVENT SUMMARY:Status of a calibration neutron monitor experiment DTSTART;VALUE=DATE-TIME:20070707T161800Z DTEND;VALUE=DATE-TIME:20070707T163000Z DTSTAMP;VALUE=DATE-TIME:20260914T185716Z UID:indico-contribution-81-0-849@cern.ch DESCRIPTION:Speakers: Prof. MORAAL\, Harm (NWU\, Potchefstroom\, South Afr ica)\nAt the previous ICRC\, Kruger et al. 2005\, Proc. 29th ICRC\, Pune\, 2\, 473\, and 2\, \n477\, reported on the first tests of two newly constr ucted calibration neutron \nmonitors. These monitors are designed to provi de an intercalibration between the 50-\nodd neutron monitors around the wo rld\, so that rigidity spectra can be calculated \nfrom them. In those pap ers we described the difference in the latitudinal (energy) \ndependence b etween the calibrator and a standard 3NM64 neutron monitor. We also \nrepo rted on a larger than expected instrumental temperature effect on the \nca librator\, being 0.12%/ degree C. Here we summarize these results and repo rt on \nnew experiments on the sensitivity of the calibrator to its enviro nment\, in \nparticular to different ground surfaces. These surface effect s have to be \neliminated in the calibration procedure for the stationary neutron monitors.\n\nhttps://indico.nucleares.unam.mx/event/4/session/81/c ontribution/849 LOCATION:Merida\, Mexico Yucatan I (Fiesta Americana) URL:https://indico.nucleares.unam.mx/event/4/session/81/contribution/849 END:VEVENT BEGIN:VEVENT SUMMARY:Observation of thermal neutron flux variations connected with Luna r periods. DTSTART;VALUE=DATE-TIME:20070707T163000Z DTEND;VALUE=DATE-TIME:20070707T164200Z DTSTAMP;VALUE=DATE-TIME:20260914T185716Z UID:indico-contribution-81-0-932@cern.ch DESCRIPTION:Speakers: Dr. ALEKSEENKO\, Victor (Institute for Nuclear Resea rch\, Baksan Neutrino Observatory\, Russia)\nBaksan Neutrino Observatory results on variations of thermal\nneutron flux near \nthe ground surface m easured with an open scintillator\ndetector are presented. \nExperimental evidences were obtained of correlation between\nthe long-term thermal \nne utron flux variations and the lunar periods (Radon-neutron\ntidal waves).\ n\nhttps://indico.nucleares.unam.mx/event/4/session/81/contribution/932 LOCATION:Merida\, Mexico Yucatan I (Fiesta Americana) URL:https://indico.nucleares.unam.mx/event/4/session/81/contribution/932 END:VEVENT BEGIN:VEVENT SUMMARY:Long-term changes in cosmic rays derived from cosmogenic radionucl ides DTSTART;VALUE=DATE-TIME:20070707T164200Z DTEND;VALUE=DATE-TIME:20070707T165400Z DTSTAMP;VALUE=DATE-TIME:20260914T185716Z UID:indico-contribution-81-0-1004@cern.ch DESCRIPTION:Speakers: Prof. BEER\, Juerg (EAWAG)\nCosmogenic radionuclides can be considered as surrogates for a neutron monitor because they are pr oduced mainly \nby the interaction of cosmic ray neutrons with nitrogen an d oxygen in the atmosphere. Measured in natural \narchives such as ice cor es (10Be) and tree rings (14C) they record the cosmic ray intensity. Compa red to manmade \nneutron monitors their time resolution is low (years) and their signal to noise ratio is relatively small. However\, they \noffer t he unique opportunity to reconstruct the history of cosmic rays over at le ast the past 10’000 years. By \ncomparing records of different cosmogen ic radionuclides from different sites the potential and the limitations of this \ntype of neutron monitor is discussed.\n\nhttps://indico.nucleares. unam.mx/event/4/session/81/contribution/1004 LOCATION:Merida\, Mexico Yucatan I (Fiesta Americana) URL:https://indico.nucleares.unam.mx/event/4/session/81/contribution/1004 END:VEVENT END:VCALENDAR