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The Cosmic Ray Observatories at IGEF-UNAM. José Fco Valdés-Galicia- PI Octavio Musalem Alejandro Hurtado Luis Xavier Gonzalez Jesús Alvarez Bernardo Vargas Ernesto Ortiz Rocío García Marcos Anzorena. Neutron Monitor And Muon Telescope. Monitor Type 6-NM64

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slide1

The Cosmic Ray Observatories

at IGEF-UNAM

José Fco Valdés-Galicia- PI

Octavio Musalem

Alejandro Hurtado

Luis Xavier Gonzalez

Jesús Alvarez

Bernardo Vargas

Ernesto Ortiz

Rocío García

Marcos Anzorena

slide2

Neutron Monitor And Muon Telescope

Monitor Type 6-NM64

Geographic Latitude = 19.33 °

W Longitude = 99.18 °

Altitude (asl) = 2274 m

Cutoff Rigidity = 8.23 GV

slide5

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
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
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.
slide8

EMBEDDED DATA ADQUISITION SYSTEM FOR

COSMIC RAY DETECTION

AMPLIFICATION AND DISCRIMINATION

STAGE

PRESSURE SENSOR

TEMPERTURE SENSOR

FPGA

EMBEDDED DATA ADQUISITION

SYSTEM

USB-I2C INTERFACE

MAX232

INTEGRATED

TIMING SYSTEM

  • Over fifty data acquisition channels
  • Cross platform graphical user interface
  • Adaptable acquisition time for high energy solar events
  • Pulse width measurement for neutron detector
slide9

Upgrading our Neutron Monitor

  • 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.

slide11

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/plastic

Scintillators

slide15

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 γby nuclear reaction inside the Sci

slide16

Solar 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°.

slide17

■ Clear excesses were recorded by

solar neutron channels, after the

hard 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.

slide18

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).

slide19

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.

slide20

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 indexα of the september 7 2005 event is most likely close to 3.

slide21

THE FUTURE AT SIERRA NEGRA

PROTOTYPE NEXT WEEK

SSNT, NEXT MARCH IN TONANZINTLA,PUE

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