i. angelov un/esa/nasa/jaxa workshop on the international heliophysical year 2007 and basic space...
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I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Muon TelescopesMuon Telescopes at Basic Environmental Observatory at Basic Environmental Observatory
Moussala and Moussala and South-West University - BlagoevgradSouth-West University - Blagoevgrad
I. Angelov, E. Malamova, J. Stamenov
INRNE – BAS, SWU “N. Rilski”
Presenter : I. Angelov
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Institute for Nuclear Research and Nuclear Energy, BAS
Basic Environmental Observatory – Moussala
42°11’N , 23° 35’E , 2925 m a.s.l.
South West University “N. Rilski” Blagoevgrad
Department of Physics
42°01’N , 23° 06’E , 383 m a.s.l.
Observation sites
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Outline
1) Description of the instruments.
2) Main characteristics of the telescopes.
3) Examples of experimental data.
4) Summary
5) Future plans.
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Detectors setup
Moussala – 1 m2 , 2x2
configuration, 1m between detectors planes
Blagoevgrad – 2.25 m2 , 3x3 configuration, 1.5 m between detectors planes
Both telescopes use water cherenkov detectors
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Detectors setup
• Mirror container 50x50x12.5 cm• 10 cm distilled water as radiator• 2.5” , 12 dynodes photomultiplier FEU-110, FEU-139
• PMT in single electron counting• 300 Ohm anode load• 90 MHz bandwidth amplifier with gain x50• discriminator threshold 15 – 50 mV• 60 ns ( 45 ns ) TTL pulses formed
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Coincidence circuits and data acquisition system
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
1200 1300 1400 1500 1600 1700 1800 1900 2000
0
20
40
60
80
100
120
140
160
180
D1U-D1D D2U-D2D D3U-D3D D4U-D4D
CO
INC
IDE
NC
E C
OU
NT
S P
ER
15
SE
CO
ND
S
HIGH VOLTAGE, V
Detectors adjustment :
• plateau in the counting characteristics
• fixed thresholds are selected – 28 mV for Moussala
– 22 mV for Blagoevgrad
• optimal HV is chosen for each detector
Dependance of the count rate – vertical coincidences on the HV for the four pairs of detectors of the telescope at BEO
Detectors adjustment
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Direction Angular interval, deg
Number detector pairs
Count-rate, min-1
Statistical error for 1h
Vertical +18.4 -18.4 9 878 0.44%
NS 0 - 33.7 6 438 0.61%
SN 0 - 33.7 6 438 0.61%
WE 0 - 33.7 6 455 0.6%
EW 0 - 33.7 6 455 0.6%
Direction Angular interval, deg.
Number detector pairs
Count-rate, min-1
Statistical error for 1h
Vertical +25.6 -25.6 4 2387 0.27%
NS 0 - 45 2 814 0.45
SN 0 - 45 2 704 0.49%
WE 0 - 45 2 756 0.47%
EW 0 - 45 2 734 0.48%
Angular directions and count rates
SWU telescope count rates =>
BEO telescopecount rates =>
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
BEO telescope :
• 40 cm concrete above the detectors; 5 cm Pb ;
• ~ 0.45 GeV energy threshold for CR muons
SWU telescope :
• 160 cm concrete above the detectors; 5 cm Pb ;
• ~ 1 GeV energy threshold for CR muons
the MMC (Muon propagation Monte Carlo) software was used for calculation (Chirkin and Rhode, 2004, 2005)
Energy thresholds and response to primary protons
BESS spectrometer at mount Norikura – 2770 m a.s.l. , Rc=11.2 GV. (Sanuki et al., 2003) kinetic energies ~ 0.48 – 106 GeV I0 0.0105 cm-2s-1ster-1
Count rate 580 min-1 - Moussala telescope 2925 m a.s.l. , Rc=6.3 Gv,corresponds to I0 0.0188 cm-2s-1ster-1
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
10 100 10000.00
0.04
0.08
0.12
0.16
0.20
0.24
0.28
0.32
Rel
ativ
e p
art
of
the
tota
l m
uo
n f
lux
Energy of primary protons, GeV
10 100 10000.00
0.04
0.08
0.12
0.16
0.20
0.24
0.28
0.32
Rel
ativ
e p
art
of
the
tota
l m
uo
n f
lux
Energy of primary protons, GeV
Energy thresholds and response to primary protons
Results from simulations with PLANETOCOSMICS code
Response to primary protons generated muons – BEO telescope
90% of the counted muons generated from protons with energies above 10 GeV
Response to primary protons generated muons – SWU telescope
90% of the counted muons generated from protons with energies above 15-20 GeV
Rc6.34 GV
Rc6.24 GV
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
680 690 700 710 720 730 740 750-8
-6
-4
-2
0
2
4
6
8
10
12
Ver
tica
l f
lux,
%
pressure, hPa
940 950 960 970 980 990 1000-10
-8
-6
-4
-2
0
2
4
6
8
10
Ve
rtic
al
flu
x, %
pressure, hPa
Meteorological corrections
Barometric effect for CR muons SWU muon telescope
= -0.1245 / % hPa
Barometric effect for CR muons BEO muon telescope
= -0.2845% / hPa
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
-0.12
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
0.02
0.04
2015105
27
Va
ria
tio
n o
f C
R
,
VE
RT
ICA
L c
ou
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1
Date, 27 October - 21 November 2003
Forbush decrease October – November 2003, SWU telescope
FD in october – november 2003
(HALLOWEEN SPACE WEATHER STORMS OF 2003)
<= SWU telescope, pressure corrected 1h data.
<= Athens NM data
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Forbush decrease December 2006, BEO telescope
FD in December 2006
(after the GLE of 13 December)
<= BEO telescope, pressure corrected 1h data.
<= Athens NM data
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Summary
• Two operational muon telescopes in BG ( Rc6.3 GV )
at ~380 m. a.s.l., 2.25m2 detectors , 1 GeV energy threshold, 0.45% statistical error for 1h intervals (after reconstruction since November 2007)
at ~2925 m. a.s.l., 1m2 detectors, 0.45 GeV energy threshold, 0.27% statistical error for 1h intervals, (since August 2006)
• Detectors of original construction, easy to build and cost effective.
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Future plans
• Coincidence circuits and counters controller upgrade, using FPGA - all combinations of UP and Down detectors
• A possibility to upgrade to higher number of detectors at South West University exists – enough room space ;
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Thanks for the attention !
The BEO muon telescope was constructed and funded as a part of the FP6 BEOBAL project - BEO Centre of Excellence Research Capacity Improvement for Sustainable Environment and Advanced Integration into ERA.
Questions, comments and ideas are WELCOME.
I. Angelov UN/ESA/NASA/JAXA Workshop on the International Heliophysical Year 2007 and Basic Space Science 2-6 June 2008, Sozopol, Bulgaria
Basic references
Hamamatsu Photonics K. K. Photon counting using photomultiplier tubes, 2005 http://sales.hamamatsu.com/assets/applications/ETD/PhotonCounting_TPHO9001E04.pdf
Chirkin D., Rhode W., All Lepton Propagation Monte Carlo, Proceedings of the 29th ICRC, Pune, 2005, http://icrc2005.tifr.res.in/htm/Vol-Web/Vol-19/19093-usa-chirkin-D-abs2-he21-poster.pdf
Chirkin D., Rhode W., Muon Monte Carlo: a high-precision tool for muon propagation through matter, 2004, http://arxiv.org/PS_cache/hep-ph/pdf/0407/0407075v1.pdf
Sanuki T., Fujikawa M., Abe K. et al, Measurements of atmospheric muon spectra at mountain altitude, 2003, http://arxiv.org/PS_cache/astro-ph/pdf/0205/0205427v3.pdf
Desorgher L., PLANETOCOSMICS Software User Manual, 2005,