Radio Detection of Neutrinos and Cosmic Rays: ANITA and ARA

33 Pages·2013·15.21 MB·English

Radio Detection of
Ryan Nichol
Neutrinos and Cosmic
Rays:
ANITA and ARA
16th Lomonosov Conference on Elementary Particle Physics
Outline
• Historical Context
• GZK Mechanism
• Radio Emission Mechanisms
– In Dense Media
– In Air
• Earlier Experiments
• ANITA
– Neutrino Search
– Cosmic Ray Air Shower Detection
• ARA
– Design
– Sensitivity
• Summary
2
(Selected) Radio Detection Timeline
Radio experiments
John V. Jelley et al at Haverah Park,
record first radio Jodrell Bank,
pulses associated Mount Chacaltaya,
with high energy Penticon, Medicini,
particles (from an Dublin and
air shower) Kharkov
1964/5 1966-75
1962 1966
Gurgen Askaryan Trevor C. Weekes,
hypothesises who actually
coherent radio recorded the first
emission from radio event, is
particle cascades awarded the first
in dielectric media PhD for the radio
detection of cosmic
3
rays
Timeline (continued)
The
The first RICE
CODALEMA
antennas were
and LOPES
deployed in
experiments,
conjunction
revisit the radio
with the
detection of air
AMANDA array
showers
1996/7 2002-
1983 1996-2000 2006-
Gusev and The first
The Parkes and
Zheleznykh ANITA flight
Goldstone radio
propose launches
telescopes stare
constructing a from
at the moon
“radio detector for Williams
(looking for
muons and Field,
neutrinos).
neutrinos” in ice. Antarctica
4
Interest in Radio Detection
• Measured in number of papers presented orally at the
International Cosmic Ray Conference.
40.0
30.0
20.0
10.0
0
57913579135701357913 7 13
5 9
66677777888899999900 0 11
0 0
99999999999999999900 0 00
0 0
11111111111111111122 2 22
2 2

.
nyttrnvoseawenyen ga a go
C
ndoalgraapesobarenvenchelodliKyotParialoraJollscoelaidDublialgarRomurbake mburukubPuneerid*Est)eijinRi
LoCudHDuP ngLMod C DLaas M (B
M a A HT z
B
t d
B
l
a o
S L
Thanks to T. Weekes and H. Badran, for the 20th century data 5
Aside -- The GZK Effect
log (E/eV)
10
18 18.5 19 19.5 20 20.5 • Greisen-Zatsepin-
]
2
V
Kuzmin (GZK)
e
1 σsys(E)=22%
-
sr 1038
1
- calculated cosmic rays
r
y

2
-
m
above 1019.5eV should
k
[

)
E
(
J be slowed by CMB

3
E HiRes
1037
Auger within 50MPc.
power laws
power laws + smooth function • Berezinksy and
1018 1019 1020 Zatsepin realised this
Energy [eV]
would produce a flux of
Figure 5: The combined energy spectrum is fitted with two functions (see text) and compared to data from the HiRes instrument [43]. The
systematic uncertainty of the flux scaled by E3 due to the uncertainty of the energy scale of 22% is indicated by arrows. A table with the Auger
fluxvalues can befoFundraot[4m4]. : Phys.Lett.B685:239-246,2010 (Auger)
neutrinos
(CNPq), Financiadora de Estudos e Projetos (FINEP), Onderzoek (NWO), Stichting voor Fundamenteel
Fundac¸a˜o de Amparo a` Pesquisa do Estado de Rio de Onderzoek der Materie (FOM), Netherlands; Ministry
Janeiro (FAPERJ), Fundac¸a˜o de Amparo a` Pesquisa do of Science and Higher Education, Grant Nops. 1+P 0ϒ3 → Δ* → n + π+
CMB
Estado de Sa˜o Paulo (FAPESP), Ministe´rio de Cieˆncia D 014 30, N202 090 31/0623, and PAP/218/2006,
+ ➘ µ+ + ν
e Tecnologia (MCT), Brazil; AVCR AV0Z10100502 Poland; Fundac¸a˜o para a Cieˆncia e a Tecnologia,
µ
and AV0Z10100522, GAAV KJB300100801 and Portugal; Ministry for Higher Education, Science, and
➘ e+ + ν + ν
KJB100100904, MSMT-CR LA08016, LC527, Technology, Slovenian Research Agency, Slovenia; µ e
1M06002, and MSM0021620859, Czech Republic; Comunidad de Madrid, Consejer´ıa de Educacio´n de
Centre de Calcul IN2P3/CNRS, Centre National de la Comunidad de Castilla La Mancha, FEDER funds,
la Recherche Scientifique (CNRS), Conseil Re´gional Ministerio de Ciencia e Innovacio´n, Xunta de Galicia,
Ile-de-France, D=e´par te“mGent Puhysaiqure Naucnle´aitreeet eCord- ” SNpaine; SucietnrceinandoTe c“hnBologey Faacimlities”C!ouncil,
6
pusculaire (PNC-IN2P3/CNRS), De´partement Sciences United Kingdom; Department of Energy, Contract
de l’Univers (SDU-INSU/CNRS), France; Bundesmin- Nos. DE-AC02-07CH11359, DE-FR02-04ER41300,
isterium fu¨r Bildung und Forschung(BMBF), Deutsche National Science Foundation, Grant No. 0450696,
Forschungsgemeinschaft (DFG), Finanzministerium The Grainger Foundation USA; ALFA-EC / HELEN,
Baden-Wu¨rttemberg, Helmholtz-Gemeinschaft European Union 6th Framework Program, Grant No.
Deutscher Forschungszentren (HGF), Ministerium MEIF-CT-2005-025057, European Union 7th Frame-
fu¨r Wissenschaft und Forschung, Nordrhein-Westfalen, work Program, Grant No. PIEF-GA-2008-220240,and
Ministerium fu¨r Wissenschaft, Forschung und Kunst, UNESCO.
Baden-Wu¨rttemberg, Germany; Istituto Nazionale di
[1] R. Abbasi et al. (HiRes Collab.), Phys. Rev. Lett. 100 (2008)
Fisica Nucleare (INFN), Ministero dell’Istruzione,
101101 andastro-ph/0703099.
dell’Universita` e della Ricerca (MIUR), Italy; Consejo [2] J. Abraham et al. (Pierre Auger Collab.), Phys. Rev. Lett. 101
Nacional de Ciencia y Tecnolog´ıa (CONACYT), (2008) 061101 andarXiv:0806.4302 [astro-ph].
[3] K.Greisen, Phys.Rev.Lett.16(1966) 748.
Mexico; Ministerie van Onderwijs, Cultuur en Weten-
[4] G.T.ZatsepinandV.A.Kuz’min,Pis’maZh.Eksp.Teor.Fiz.4
schap, Nederlandse Organisatie voor Wetenschappelijk
(1966) 114.
11
Radio Emission
Mechanisms
Vertical Iron Shower at LOPES
frequencies from T. Huege et al.
ARENA2012
Radio Emission -- Early Theory
• Early theoretical work by Gurgen Askaryan predicted
coherent Cherenkov radiation from air showers.
• The geomagnetic contribution was first proposed by
Downloaded from rspa.royalsocietypublishing.org on 19 June 2009
Kahn and Lerche in 1965.
8
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Proceedings of the Royal Society of London. Series A, Mathematical and Physical Sciences.
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Radio Cherenkov -- The Askaryan Effect
• In 1962 Gurgen Askaryan hypothesised coherent
radio transmission from EM cascades in a dielectric:
Typical Dimensions:
e± or ϒ
L ≈ 10 m
R ≈ 10 cm
Moliere
– 20% Negative charge excess:
• Compton Scattering: + e- (cid:15482) + e-
𝞬! (rest) 𝞬
• Positron Annihilation: e+ + e- (cid:15482)
(rest) 𝞬
– Excess travelling with, v > c/n
• ν ν
Cherenkov Radiation: dP ∝ d
– For λ > R emission is coherent, so P ∝ E2

shower
9
WWhheerree ddooeess AAsskkaarryyaann wwiinn??
2
Askaryan Effect in the Laboratory
! Huge dynamic range ! SNR dominant for E > 10 PeV
END STATION A side view
crane hook: 13.7m
Approximately to scale 3m
13.4m
10.7m 4.8m
beamline
4m
1.2m
2.4m
Ryan Nichol University College London, 19th September 2005 13
10m 3
PRL 99, 171101 (2007)

see also:

PRE 62, 8590 (2000),
2
FIG. 2: (color online) Left: Thse1ANITA payload (center) above and PRL 86, 2802 (2001),
olt PRD 72, 023002 (2005)
v 0
payload downstream of the ice target e (here covered). Right top, target with
c PRD 74, 043002 (2006)
n −1
e
cover removed, in ambient lighert. Right bottom: ice target illuramw iminpualset reesdponse
ef −2
r partially deconvolved
−3
from interior scattered optical Cherenkov radiation.

−20 −15 −10 −5 0 5 10 15 20 25 30
Cherenkov time, ns
z 40
cone H
M
20
m/
V/ 0
8 m h,
gt −20
n
and validation than observeat−i40ons of scalar intensity. raw RF Cherenkov
r
st partially deconvolved
d −60 10
el
The experiment, SLACfiT4 86, was performed in the End
−20 −15 −10 −5 0 5 10 15 20 25 30
time, ns
Station A (ESA) facility during the period from June 19-24,
2006. A target of very pFuIGre. 3c: aTrovp:inRagw-,ganrdadpaertiiacllye-dwecoansvoclvoednismtpruulscetreesdponse of
ice
the ANITA receiver system. Bottom: Pulse received during the T486
from close-packing rectangular 136 kg blocks (about 55 were
experiment in an upper-ring antenna near the peak of the Cherenkov
target
cone, also showing the raw pulse, and partially partially-deconvolved
used) to form a stack approximately 2 m wide by 1.5m tall
response. The apparent “ringing” artifact of the raw impulses is due
(at the beam entrance) by 5 m long. The upper surface of
to group delay variation of the passband edges of the bandpass filters
employed.
the ice was carved to a slope of 8 in the forward direc-
15 m FIG. 4: Left: Field strength vs. frequency of radio Cherenkov radia-
◦
∼
tion in the T486 experiment. The curve is the theoretical expectation
tion giving the block a trapezoidal longitudinal cross section
for a shower in ice at this energy. Right: Quadratic dependence of
along the beam axis. This was done to avoid total-internal the pulse power of the radiation detected in T486, indicating the co-
The ice was contained in a 10 cm thick insulating foam-lined herence of the Cherenkov emission.
reflection (TIR), of the emerging Cherenkov radiation at the
box, and a 10 cm foam lid was used during operation, along
FIG. 1: Top: Side view schematic of the target and receiver arrange-
surface. The surface afwtiethracfarerevzeirnugnitw, taosmaminetaainsutermepderattourehs aofvbeetwaeen -5
ment in ESA. Bottom: Perspective view of the setup, showing the
to -20 C. Such temperatures are adequate to avoid significant
root-mean-square (rms) roughness of 2.3 cm. The beam en-
key elements. RF absorption over the several m pathlengths of the radiation In Figure 4 (left) we display measurements of the abso-
tered this target about 40thrcomughatbheoivcee[9t]h. e target floor, which was lute field strength in several different antennas, both upper
The ANITA payload, consisting of an array of 32 dual- and lower quad-ridged horns, bicone, and discone antennas.
lined with 10 cm ferrite tiles to suppress reflections off the
polarization quad-ridged horn antennas was used to receive The discone and bicone antennas have a nearly omnidirec-
bottom.
the emission at a location about 15 m away from the center of tional response and complement the highly directive horns
the target, as shown in Fig. 2. The antenna frequency range by providing pulse-phase interferometry. The uncertainty in
The showers were produced by 28.5 GeV electrons in
is from 200-1200 MHz, which covers the majority of the fre- these data are dominated by systematic, rather than statistical
9
Despite confirmation of Askaryan’s theory for sand and 10 picosecond bunchesquoenfcytyrapngiecoavlelrywh1ic0h thpe RarFttircanlesms.issivMityoofnitcee-is at its errors, and are about 40% in field strength ( 3 dB). These
± ±
highest [9]. Eight additional vertically polarized broadband are dominated by a combination of the 1-2dB uncertainty in
Carlo simulations of the showers indicate that about 90% of
salt, there are important reasons to test it in ice as well, since
monitor antennas (four bicones and four discones) are used the gain calibration of the antennas, and by comparable un-
the shower was contained in the target; the remainder was
so much study and experimental effort have been directed at to complement the suite of horn antennas. The ANITA horn certainties in removing secondary reflections from the mea-
antennas are arranged so that adjacent antennas in both the sured impulse power. The field strengths are compared to a
dumped into a pair of downstream concrete blocks. In contrast
ice as the target medium. First, although the effect is primar-
lower and upper payload sections respond well even to a sig- parameterization based on shower+electrodynamics simula-
to previous experiments [5, 12], we did not convert the elec-
ily determined by shower physics, the radio production and nal directed along their nearest neighbors’ boresights. This tions for ice [10, 11], and the agreement is well within our
trons to photons via a balrloewms mssutltriaplhelauntnengnarsa(dtyipaictaollry.4 tSou6chhornms aentdh3-to 4 of experimental errors. Figure 4(right) shows results of the scal-
transmission occurs under conditions where the properties of
the bicone/discones) to sample the arriving wavefront. The ing of the pulse power with shower energy. The dependence is
ods were used in earlier Askaryan discovery experiments to
the medium could play a role in modifying the behavior of the
signals are digitized by custom compact-PCI-based 8-channel completely consistent with quadratic scaling over the energy
avoid any initial excess dcihgiatizregremiondutlhese[2s2h],o9woef rwhdiechvaerleoupsemd etonrte.coIrnd all 72 range we probed, indicating that the radiation is coherent over
emission; the possibility of unknown media-dependent effects
antenna signals simultaneously at 2.6 Gsamples/sec. the 200-1200 MHz frequency window.
our case, the typical shower had a total composite energy of
which might suppress the emission must be explored. Sec-
Figure 3 shows an example of the impulse response of the Figure 5 shows the measured and predicted angular depen-
19 10 +
3 10 eV, with a total of 2 10 e e pairs at shower
ond, the radio Cherenkov method is most effective at shower system (top), and one of the measured waveforms near the dence of the radiation. The Cherenkov cone refracts into the
−
× ∼ ×
peak of the Cherenkov cone. The apparent “ringing” of the re- forward direction out of the ice, and is clearly delineated by
maximum. EGS simulations of the charge excess develop-
energies above 10-100 PeV, where muon or other cosmic-
ceiving system is due to the group delay of the edge response the data. Here we show statistical+systematic errors within
ment indicate a net charge asymmetry of about 20%. Thus the
ray backgrounds are negligible, and the method thus “suf-
of the bandpass filters, but most of the energy arrives within a a measurement run; the overall normalization (with separate
initial electrons contribufrtaectaiotnmofoasntanose1c5on%d, aosfdettheremtinoetdailnnpreegviaoutisvmeeasure- systematic error) is taken from Fig. 4. We scale these data
fers” from the virtue of having no natural backgrounds with
ments of the As∼karyan effect [7]. In the measured T486 wave- within the overall systematic errors to match the peak of the
charge excess in the shower, and we have corrected for this
which to calibrate the Cherenkov intensity and corresponding
form of Fig. 3 (bottom), later-time reflections from shielding field strength. The radiation frequency limit where full coher-
bias in the results we shaonwd rahileinrgen.eaIrnthaedtadrigteito, ans,wrealldaisothaebpsaoylrobadinstgructure, ence obtains is given approximately by the requirement that
detection efficiency. In this context, laboratory calibrations
introduce some additional power into the pulse tail. kL 1, where the wavenumber k = 2πnν/c for frequency
of the radiation behavior are critical to the accuracy of results. foam was in place on the front face of the ice, and very effec- !
tively suppressed RF signals from the upstream metal beam
And finally, the increased richness of these radio observations,
vacuum windows and air gaps.
which directly measure electric field strength and vector polar-
ization, require more comprehensive experimental treatment A schematic of the experiment layout is shown in Fig. 1.