The MARIACHI experiment- Ideas on Radar Detection of UHECR

The MARIACHI Experiment
Radar detection of UHECR
Helio Takai
Physics Department, Brookhaven National Lab. &
Dept. of Physics and Astronomy, Stony Brook University
[email protected]
Motivation
Radar can potentially cover larger detection
areas for the detection of ultra high energy
cosmic rays.
Radar can potentially be used to detect
horizontal showers produced, e.g. by high energy
neutrinos.
Radio vs Radar
Radio - Detection of Radio Frequency from Cosmic
Ray Shower, i.e. Geo-Synchrotron Radiation.
Radar - Detection of Radio Frequency scattered of
the ionization created by a Cosmic Ray Shower.
However: They both share similar type of problems,
namely, antenna design, receivers, data
acquisition, and more importantly noise!
There are (at least) two types of radar: monostatic
and bistatic.
Radio
G.A. Askaryan Sov. Phys. JETP 14(1962) 441(and others).
CASA/MIA and Radio - K. Green et al., NIM A498 (2003) 256.
Synchrotron Radiation at radio frequencies from Cosmic ray
showers. D. Suprun et al., Astroparticle Phys. 20(2003)157
Accelerator measurements of the Askaryan effect in rock salt: A
roadmap toward teraton underground neutrino detectors, P.
Gorham et al., Phys. Rev. D 72, 023002 (2005)
CODALEMA - Radio detection of cosmic ray air showers by the
CODALEMA experiment, O. Ravel et al. NIM A 518(2004)213
LOPES - Falcke et al. (LOPES collaboration) Nature(2005)435
Radar
P.M.S. Blackett and A.C.B. Lovell, Radio Echos and Cosmic Ray
Showers, Proc. Roy. Soc. A 177(1940)183.
K. Suga, Methods for Observing Extremely Large Extensive Air
Showers, Proceedings of the Fifth Interamerican Seminar on Cosmic
Rays, La Paz, Bolivia (1962) XLIX-1.
T. Matano, M. Nagano, K. Suga, and G. Tanahashi,Tokyo large air
shower project, Canadian Journal of Physics, Vol. 46 (1968) S255.
P. Gorham, On the possibility of radar echo detection of ultra high
energy cosmic ray and neutrino induced extensive air showers,
Astroparticle Physics 15(2001)177.
A. Iyono, N. Ochi, Y. Fujiwara, T. Nakatsuka, S. Tsuji, T. Wada, I.
Yamamoto, Y. Yamashita, Radar Echo Detection System of EAS
Ionization Columns as Part of a LAAS Detector Array, Proc. of the 28th
International Cosmic Ray Conference. July 31-August 7, (2003) 217
The Radar Technology Concept
Key Concept: Free electrons will reflect electromagnetic
waves via Thomson Scattering.
When electron density is very high the reflection regime
is specular: plasma scattering.
!
ne e2
νp =
πme
Forward Scattering has more scattered power, thus
bistatic radar is the favored technique.
Locate Transmitter far from Receiver.
Radio Meteor Scatter
Meteors when entering earth’s atmosphere
vaporizes, and creates an ionized trail.
Radio waves from far (600-2000 km typical) are
reflected by the ionization created by them.
120km
Meteor
80km
Pittsburgh
BNL
Holdsworth,Reid and Cervera
Estimating Scattered Power
Cosmic Rays with E > 1018 eV will produce a cylindrical
ionization of few meters in diameter with densities larger than
the plasma frequencies for frequencies between 50-100MHz.
The same formalism used for meteors forward radio scattering
can be used as an estimator.
PT GT GR λ3 q 2 re2 sin2 α
PR (t) =
16π 2 RT RR (RT + RR )(1 − cos2 β sin2 φ)
8π 2 r02
32π 2 Dt
· exp(− 2 2 ) · exp(− 2 2 )
λ sec φ
λ sec φ
Selected list of Problems
Lifetime - The ionization happens at low altitudes (<20km).
This means short “free electron” lifetime.
Dampening - While electrons are oscillating they will
scatter from neutral molecules and others causing
dampening.
Refractive media - Surrounding the dense ionization core
there is a “haze” of electrons. This media is refractive and
needs to be considered. (not covered today)
Polarization - Loss of polarization is possible as it is
observed in meteor scattering.
Received Power
(For long lifetime)
−12.4
−9.5
−12.6
ower(
log(P
−12.8
−13.0
−13.2
−13.4
−13.6
−13.8
−14.0
20000
25000
30000
35000
40000
45000
50000
55000
60000
65000
70000
75000
80000
a.u.))
a.u.))
ower(
log(P
Trans.
Trans.
x
30000
25000
20000
15000y
10000
5000
Rec.
Horizontal Showers
30000
25000
20000
15000y
x
−10.0
−10.5
−11.0
−11.5
−12.0
−12.5
−13.0
−13.5
20000
25000
30000
35000
40000
45000
50000
55000
60000
65000
70000
75000
80000
10000
5000
Rec.
Vertical Showers
100W transmitter located at 100 km from receiver.
Note: 80km is about the limit for flat earth approximation.
Received Power and Signal Duration
τ~250 ns (depends on
ionization mechanism)
0AST
Zg
L
H
Z
t ∼ 50 µs
Z
Yg
Y
4RANSMITTER
Y
ZO
X
PR ∼ 10−12 W atts
&UTURE
YO
X
XO
Xg
2ECEIVER
Received power τ→∞
Dampening adds an
attenuation of 10-4, with
νe~109,
fscat
m2e
1
= 2(
)
M (νe /πν)2 + 1
PR ∼ 10
−16
W atts
Sky Noise
PN = k · Teq · B ∼ 10−18 W
D. Krauss
Noise
Your noise is somebody else’s signal!
Man Made
Computer, Spark Plug, Airplane, Transformer,
Fluorescent Lamp, Radar, TV, Radio, Walkie-Talkie,
Cell Phone, Photo tubes, Electronics, etc....
Natural
Aurora, Sporadic-E, Meteor, Lightning, Clouds, Sun,
Galaxies, etc....
We need to understand it!
Antennas
CODALEMA
LOPES
LWA
Our Antenna
Double Inverted V Dipole.
When phased properly it has
the following radiation pattern:
An amplifier will be installed in
the “can” for long cable runs.
The problem with antennas: GROUND
Receivers, Transmitters and GPS.
Fast developing new technologies. Computer
controlled radio available for systematic scans.
Radio Astronomy in the 10-200MHz range (decametric)
has developed radio receivers for phased arrays.
GPS conditioned frequency generators is a reality.
Software Defined Radio for example GNU Radio.
Good timing with GPS.
Experimental Setup
Ideally it should
be our own
Transmitter
Incident Wave
UHECR Shower
$ISTANT
4RANSMITTER
Scattered Wave
-ONITORING
3TATION
Shower Detector
5 scintillation counters
installed in High Schools
RCRS Detector
Phased array?
Stations are distant and independently operated.
TV Broadcast Stations
1UEBEC
Lake
Superior
/TTAWA
Augusta
Lake
Huron
Montpelier
L. Ontario
Concord
Albany
N
Lake
n Michigan
ee
Buffalo
Lansing
Detroit
Chicago
Hartford
L. Erie
Philadelphia
Cleveland
Gary
Ft. Wayne
Pittsburgh
Indianapolis
Springfield
Cincinnati
Frankfort
Charleston
Louisville
Richmond
Roanoke
Durham
Nashville
Memphis
Knoxville
Charlotte
Portland
Norfolk
Raleigh
Boston
Estimated
detection area
~6000 km2
Mixed Apparatus for Radar Investigation of
MARIACHI Atmospheric Cosmic-ray of Heavy Ionization
www-mariachi.physics.sunysb.edu
Sample Meteor Signal
E-W
N-S
Lightning
Reflection
Lightning produces a lot of
ionization!
db/mV
10
15
Direct Emission
0
5
We receive direct emission
and reflection. Perhaps
from exotic forms?
0
20
40
60
time(x0.1s)
80
100
Coincidences
1
0.4
0.8
0.2
SCCC DTV 2
SCCC
Amplitude DTV2 at SCCC
We are starting to correlate information from the 2
stations - SCCC and BNL
0.6
0.4
0.2
0
932
934
936
938
940
time(ms)
942
944
946
948
950
775
775.5
776
time(ms)
776.5
777
777.5
774.5
775
775.5
776
time(ms)
776.5
777
777.5
0.05
BNL DTV 2
Amplitude DTV2 at BNL
774.5
0.1
0.3
0.2
0.1
0
0
!0.05
!0.1
!0.15
!0.1
!0.2
!0.2
930
!0.4
!0.8
0.4
BNL
!0.2
!0.6
!0.2
!0.4
930
0
932
934
936
938
940
time(ms)
942
944
946
948
950
Distance between SCCC and BNL is ~20km, or 67 μs.
Summary
Bistatic (Multistatic) Radar seems to be a feasible
technology for the detection of UHECR.
Current estimates using modest transmission power yields
received power levels that are above noise and
detectable by current existing technology.
Software defined radio is an evolving technology (open
source software and hardware) that could be used for a
phased array detection system.
Noise is one of the most important issues in this business
since radio is everywhere.
Simultaneous runs with established cosmic ray experiments
is a must.