José Fco Valdés-Galicia- PI Octavio Musalem Alejandro Hurtado Luis Xavier Gonzalez Jesús Alvarez Bernardo Vargas Ernesto Ortiz Rocío García Marcos Anzorena.

José Fco Valdés-Galicia- PIOctavio Musalem Alejandro HurtadoLuis Xavier GonzalezJesús AlvarezBernardo VargasErnesto OrtizRocío GarcíaMarcos Anzorena

The Cosmic Ray Observatories at IGEF-UNAM

Neutron Monitor And Muon Telescope

Monitor Type 6-NM64Geographic Latitude = 19.33 °W Longitude = 99.18 °

Altitude (asl) = 2274 m

Cutoff Rigidity = 8.23 GV

Mexico - vertical penumbral zone, epoch 2000Cutoff Rigidity: 8.269 GV ± 0.615

Black zones represent forbidden arrival directions

10.09.59.08.58.07.57.06.56.0

R ig id i ty [GV ]

AÑO HELIOFÍSICO INTERNACIONAL (Naciones Unidas, 19 de febrero de 2007)

VESO (Instituto de Geofísica UNAM):

RIS Radio Interferómetro Solar (Investigaciones Solares y Planetarias)MEXART (Mexican Array Radio Telescope)

Radiotelescopio de Centelleo Interplanetario (Física Espacial)RC Observatorio de Rayos Cósmicos (Investigaciones Solares y Planetarias)TEO Observatorio Geomagnético de Teoloyucan (Geomagnetismo y Exploración Geofísica)

www.veso.unam.mx

Present status

• Online database• Five minute data from January 1st., 1997 to

September 17, 2008• One minute data since September 18, 2008.

From September 1, 1989 to December 31, 1996 upon request

• Monthly plots from January 1990 to June 2008

Present status (contd’)

• With the exception of a few bugs, data are verified and available on real time.

• All of our data will soon (DEC 2010) be available for download.

• We are renewing our data acquisition system; the new system will be based on FPGA circuit networks.

FPGA

MAX232

PRESSURE SENSOR

TEMPERTURE SENSOR

USB-I2C INTERFACE

INTEGRATEDTIMING SYSTEM

AMPLIFICATION AND DISCRIMINATION STAGE

EMBEDDED DATA ADQUISITIONSYSTEM

EMBEDDED DATA ADQUISITION SYSTEM FOR COSMIC RAY DETECTION

Over fifty data acquisition channelsCross platform graphical user interfaceAdaptable acquisition time for high energy solar eventsPulse width measurement for neutron detector

We have already six new LND 25373 He3 tubes.

We need financial support to acquire:- Lead rings.- Moderator material.- Four high voltage and two low voltage power

supplies.- Miscellaneous components.

Upgrading our Neutron Monitor

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We have another station at Sierra Negra Volcano, 4580m asl

SOLAR NEUTRON TELESCOPE•Determines neutron energy

•Directional capabilities

•Proton, neutron discrimination PC are veto for protons

Energy is resolved by peak signal height

Direction is resolved by lower gondolas

PC in coincidence w/plasticScintillators

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World Network of Solar Neutron Telescopes

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Location Height(g/cm2)

Longitude Latitude Area(m2 )

Counts without Anti (m2 /min)

Counts with Anti (m2 /min)

GronergratSwitzerland

700 7.8°E 46.0°N 4 33,000 12,000

AragatsArmenia

700 40.5°E 44.2°N 4 23,000 15,000

YanbajingTibet

600 90.5°E 30.0°N 9 34,000 8,900

Mt. NorikuraJapan

730 137.5°E 36.1°N 64 19,000 2,600

Mauna KeaHawaii

610 156.3°W 19.8°N 8 25,000 12,000

Sierra NegraMéxico

575 97.3°W 19.0°N 4 47,000 20,000

ChacaltayaBolivia

540 68°W 16.2°S 4 56,000 26,000

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Graphical output of the simulation of a vertical impinging neutron of 500 MeV.

■ n + 12CSci → p+ Triggers four PRCs underneath the Sci (marked in red).

■ Production of low energy γ by nuclear reaction inside the Sci

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Solar Neutron Event on September 7, 2005Solar Neutron Event on September 7, 2005

■ A strong solar flare occurred on Sept 7 2005 ( X17.0, E= 17x10-1 erg cm2 seg-1).

■ Maximum at 17:40 UT (GOES), 17:36:40 (Integral).

■ Sierra Negra, was a suitable site to observe solar neutrons 11:36:40 LT, Solar zenith angle ~0°.

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■ Clear excesses were recorded by solar neutron channels, after thehard X-ray peak time.

■ The statistical significance of the excesses:

S1_with_anti 16σ,

S2_with_anti 12σ,

S3_with_anti 9.9σ,

S4_with_anti 6.2σ.

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a) Simulated solar neutron flux arriving vertically to the telescope (mid-day incoming flux, zenith angle = 0°).

b) The real proportion of SNT counting rates during the event on Sept 7, 2005 at 17:36:40 UT (11:36:40 LT ~0° of zenith angle).

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Sako, et. al., 2006, & Watanabe, et. al., 2007, based on the time evolution profile observed at Chacaltaya, assuming a power law functional form, calculated the spectral index α. First using an impulsive injection and then using the 4 MeV gamma ray profile as injection function.

Sako (2007) used 1 hr (17:30 to 18:30 UT) data from the Sierra Negra SNT, a detector simulation based on GEANT3, and the atmospheric neutron atenuation calculated

by Shibata (1994) to make an estimate of α.

Spectral index results were:α = 3.1 & 3.2.

Based on GEANT4, the neutron atmospheric atenuation of Dorman & Valdés-Galicia (1999), and 45 minute data (17:30 to 18:15 UT) from the Sierra Negra SNT, we recalculated α.

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Conclusions for SNT work

■ The angular resolution of our SNT simulation is in very good agreement with real data taken during the event of September 7, 2005, constituting a validation of the simulation code.

■ From the simulation we may conclude that neutrons of ~1 GeV were observed.

■ Protons of at least 10GeV must have been produced. They were not observed as it was an east limb flare.

■ The spectral index α of the september 7 2005 event is most likely close to 3.

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THE FUTURE AT SIERRA NEGRA

PROTOTYPE NEXT WEEKSSNT, NEXT MARCH IN TONANZINTLA,PUE