Transcript Detection of 10-40 MeV electrons neutrons and gammas

Detection of 10-40 MeV electrons, neutrons
and gammas from the Relativistic Feedback
Breakdown Process by particle detectors at
Aragats
A.Chilingarian Yerevan Physics Institute, Armenia
Cosmic Ray “Showers”
Space
“Primary” Cosmic Ray
(Ion, for example a proton)
Earth’s atmosphere
Atmospheric Nucleus
p-
po
g
g
e+ eg
g
e-
Creating: Electromagnetic
p+ “Secondary” Cosmic Rays...
(about 50 produced after first collision)
po
g
p-
p+
nm
m+
muon
neutrino
Hadronic Shower
Shower
(muons and neutrinos
(electrons and g-rays) reach earth’s surface)
Plus :
Neutrons
Additional Particles from the
Thunderstorm Clouds
Aragast Solar Neutron Telescope
Construction of the SEVAN basic unit
100 – traversal of the low energy
charged particle (~<200MeV);
010 – traversal of the neutral
particle;
111 & 101 – traversal of the high
energy muon (~>250MeV);
Starting of SEVANs in Bulgaria and Croatia
Selection of Secondary Cosmic Rays
at Aragats research station 3200 m a.s.l.
Gam m a
Elect ron
Muon
Neut ron
Regist ered part icles Purit y by special com binat ion
Low energy charged part icles [ 100]
11.605
43.300
37.380
2.838
Neut ral Part icles [ 010]
50.612
8.837
4.494
35.071
High energy charged part icles [ 101] + [ 111]
0.002
0.106
94.904
0.808
Regist ered part icles Purit y by count rat e of t he det ect ors
Upper Det ect or
7.616
28.952
56.080
2.448
Middle Det ect or
11.550
5.223
67.913
11.038
Lower Det ect or
2.696
4.438
85.873
3.267
Prot on
4.804
0.972
4.077
4.814
4.167
3.634
Purity-Efficiency Diagram
Relativistic feedback breakdown (RFB)
In this mechanism, avalanches of runaway electrons emit
bremsstrahlung x rays that may either
Compton backscatter or pair produce in the gas medium.
If the backscattered photons propagate to the start of
the avalanche region and produce another runaway
electron, either via Compton scattering or photoelectric
absorption, then a secondary avalanche is created.
Alternatively, the positrons created by pair production
can sometimes turn around in the ambient electric field
and run away in the opposite direction of the electrons.
The positrons quickly become relativistic, allowing them
to travel for many hundreds of meters before
annihilating. If these positrons propagate to the start of
the avalanche region they can produce additional
runaway electrons via hard elastic scattering with atomic
electrons in the gas i.e., Bhahba scattering, thereby
producing secondary avalanches. These secondary
avalanches can in turn emit more x rays that Compton
scatter or pair produce, resulting in more feedback and
more avalanches. This positive feedback effect allows the
runaway discharge to become self- sustaining, no longer
requiring an external source of energetic seed electrons.
As a result of this positive feedback, the number of
runaway electron avalanches increases exponentially on
a time scale measured in microseconds.
AMMM evidence
21 May 2009, AMMM
Blue – electrons > 10 MeV
Pink – muons > 5 GeV
33000
32000
31000
30000
29000
3 June 2009, AMMM
28000
27000
26000
25000
16:19
16:36
16:52
17:09
UT
17:26
17:43
Relative accuracy ~0.3%;
Enhancements 25% at May 21
and 9% at June 3
Intensity[particles/min m sq]
Intensity [particles/min m sq]
34000
34000
33000
32000
18:00
31000
30000
29000
28000
27000
26000
25000
15:36
16:04
16:33
UT
17:02
17:31
ASNT: Histograms of additional
particles
ASNT: Intensities and coincidences
ASNT evidence: RFB electrons and Gammas
Energy Spectra of RBF gamma-quanta
21 May 2009
Intensity [particles/sq.m
min]
8500
8000
7500
7000
6500
6000
5500
5000
16:19
16:33
16:48
17:02
17:16
Time (UT)
17:31
17:45
18:00
RBF Gammas and Electrons
detected by SEVAN
RFB Neutrons
21 May, 2009
20
16
14
11
12
10
6
8
Dst (nT)
Relative increase of
neutrons and neutral
particles
18
16
6
1
4
2
-4
0
16:30
17:00
17:30
UT
By ANM
By Sevan (010)
Dst by Kyoto MM
Additional neutrons, born in the air are initiated by the hard
gamma-quanta in photo-nuclear reactions with air atoms.
Existence of neutrons, along with electrons and gammas is
another proof of the RFB model
Outline of the thunderstorm correlated
enhancements at 21 May 2009
May 21,
2009;
17:03-17:20
Average count
per minute
Total Count
of additional
particles
Detector
Surface
Mean
Intensity
AMMM
ASNT (60
cm)
Time of
maximal
flux UT
Maximal
minute
Intensity
#/m2
Comments
m2
#/m2/min
703,932 ± 2295
1,408,347
26
3,009
17:16
6,448
Threshold
102,035 ± 399
57,096
3
1,057
17:15
1,769
Efficiency ~ 5-10%;
~10 MeV
One of 4 detectors was
not in operation
ASNT (5
cm)
78,099 ± 304
54,993
4
764
17:15
1,769
Threshold
ASNT (11)
8643 ±92
2470
3
46
17:15
115
Threshold 25-30 MeV
SEVAN
Aragats 100
12,869 ±115
13,206
1
734
17:15
1800
Threshold ~15 MeV
SEVAN
Aragats 010
1566 ±44
1,507
0.25
335
17:16
1188
Efficiency 1-2%
ANM
33,308±212
2542
18
25
17:16
48
Efficiency 1-3%;
Duration 17:09 – 17:18
~15 MeV
Electron-photon cascade
development and lightings
% of mean count rate
120
17:20
115
110
17:11
17:07
105
100
95
90
17:00
17:05
17:10
17:15
17:20
17:25
Time
010 (gamma-quantum)
100 (electrons)
17:30
Electrical field measurements and
particle enhancements
Thunderstorm on August 6, 2003,
averaging over 15 s,
one of the longest and most
profound muon effect
 Electric field strength
 Soft component
 Muons >1 GeV
 Hard component
(muons > 90 MeV)
 Stopping muons (20-80
MeV)
Baksan measurements
Additional electrons coming vertically!!!
J. R. Dwyer,1M. A. Uman,2and H. K. Rassoul, Remote
measurements of thundercloud electrostatic fields,
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 114,
D09208, doi:10.1029/2008JD011386, 2009
EAS are composed of three basic components: the
nuclear active component, made up of very highenergy particles close to the shower axis: the muon
component, which forms a broad lateral
distribution, and the electronic component made
up of electrons, positrons, and gamma rays. The
electrons and positrons in the air shower are the
result of electromagnetic cascades continuously
generated by high-energy gamma rays
from pion decays. At thunderstorm altitudes, the air
shower is often near its maximum development.
Near shower maximum, most of the particles in the
shower are part of the electronic component. As
the air shower propagates through a high-field
region, due to their high rigidity, the nuclear and
muon components are not significantly affected
by the thundercloud electric fields. On the other
hand, the electronic component can be
substantially altered by the electric field, with
electrons deflected in one direction and
positrons in the other, depending upon the electric
field direction.
Can RBF harm EAS?
EAS(blue dots labeled EAS) entering a high electric
field region, wherein runaway electron avalanches are
produced (black dots). The electric field points
upward. The low energy electrons (red dots labeled
slow electrons) resulting from ionization by the
runaway electrons trail behind the runaway electrons.
As the air shower passes through the
high-field region, the muons and hadronic core are
not significantly deflected by the electric force, and so
the location that the air shower strikes the ground is
unchanged. However, the electric field locally causes
large deflections of the electrons (and positrons) in
the shower, which make the largest contribution to
the runaway electron seed population. For the case of
a downward electric field, the air shower still enters
through the top of the avalanche region, as shown,
and propagates to the bottom of the region. However,
the runaway electrons and the low-energy electrons
all propagate upward in this case. As the runaway
avalanches propagate and grow, the increasing electric
current produces RF emissionthat can be measured
RBF amplifies Radiosignals from EAS
Only a fraction of the events recorded during fair weather conditions has a
detected coherent signal. During thunderstorms this fraction is 2.5 times higher.
M. Endery, W.D. Apel, J.C. Arteagay et al., Radio Emission of Extensive Air Showers
during Thunderstorms, PROCEEDINGS OF THE 31st ICRC, LODZ 2009
Conclusion
• First simultaneous detection of high energy gamma-quanta,
electrons and neutrons, proving existence of the intensive
self-sustaining electron photon cascade process in the
atmosphere developing in the Earth direction;
• Simultaneous measurements of the gamma-rays, electrons
and neutrons provide unambiguous confirmation of the
photonuclear mechanism for neutron production.
• First detection of numerous long lasting events of additional
particle flux, provided by chain cascade process (positive
feedback); RFB can sustain the acceleration process in the
atmosphere for up to 30 minutes despite discharge by
lightening.
• First measurement of the energy spectra a of the
thunderstorm related gamma-quanta up to 40 MeV;
Radio-band-width monitoring
detection at Aragats
Magnetometry at Aragats
0.01 nT accuracy magnetic sensor of flux-gate type, was manufactured using well-proved technology
on the base of marble and quartz combination implementing recent findings in the excitation circuit
construction. For electric channels, a filter-free technology of input stages was accepted in order to
let to pass super-long period signals. In order to avoid the channels saturation in natural electric
field, the automatic compensation circuit is provided at the beginning of the measurements in the
range ± 250 mV.