brochure pamela mission version ing...
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a Payload for Antimatter Matter Exploration
and L ight–nuclei Astrophysics
Cosmic rays provide
a unique probe of the most
energetic processes in the Universe.
Cosmic rays are particles which were
produced during primordial
nucleosynthesis or from supernova explosions.
Most of the cosmic rays come from outside the solar system
but from within the Milky Way. During the last ten million years they
have been accelerated to nearly the speed of light, and traveled many
times across the Galaxy, trapped by the galactic magnetic field.
While astronomical observations of light from
distant objects yield clues to the state of matter in our Galaxy
and beyond, cosmic rays bring us a small but
valuable sample of that matter itself.
Through studies of the composi-
tion and energy spectra of cosmic
rays, we are able to learn about the
origin and evolution of material in our
Galaxy and about fundamental physical
processes that govern its dynamics.
The space experiment
PAMELA will perform a detailed survey of
cosmic rays across a wide energy range, thus
shedding light on the most intriguing puzzles
in this field.
origin and propagation of cosmic rays
A supernova remnant,
the Crab nebula, as
observed by the Very
Large Telescope.
The triple ring
system
surrounding
Supernova
1987A, as
detected by
the Hubble
Space
Telescope.
A pictorial view
of a supernova
explosion and a
conical section
of the
expanding cloud
of ejected
material.
Matter-Antimatter asymmetryis another fundamental question that PAMELA
will address. This question has important
ramifications for both cosmology and particle
physics.
Although antiprotons and positrons can
be produced in high-energy
cosmic-ray collisions with the
interstellar medium, heavy
antinuclei, if discovered in
cosmic rays, would provide an
unambiguous signature of the
existence of antimatter domains.
According to the Big Bang theory,
antihelium could originate in
primordial gas which has not
condensed into a star. Heavier
antinuclei could only be produced by
nucleosynthesis processes in antimatter stars.
During itsmission,
PAMELA will measure the
antiproton and positron
components in cosmic rays
with statistics never reached
before by previous experiments,
and will search for antinuclei
with an unprecedent sensitivity.
antimatter in the Universe
A cloud of positrons in
the center of the Milky
Way, seen by the
Compton Gamma Ray
Observatory.
The positrons annihilate
with electrons, thus
emitting radiation -
which can be detected.
Jets of antimatter could
be emitted by a massive
black hole in the center
of the Galaxy.
Nucleosynthesis in
ordinary stars,
producing heavy
elements. An antistar
would burn in the same
way, giving rise to
antinuclei.
The dark matterproblem is one of the most
important and intriguing questions
confronting modern particle
astrophysics and cosmology.
The root of the problem is that there
seems to be more gravitationally interacting matter than what is
visible.There has been wide spread speculation about what might constitute the dark
matter. One possible form of dark matter could be weakly interacting massive particles (WIMPs).The most
promising candidate for WIMP is the lightest supersymmetric particle that, in the minimal supersymmetric
extension of the Standard Model, is the neutralino.
Pairs of neutralinos could annihilate in the Galactic Halo, producing, among other particles, proton/antiproton
and electron/positron pairs - all of which can be detected by PAMELA.
Elemental abundances in
the solar corona can be measured by the
detection of high energy particles accelerated
in Solar Energetic Particle (SEP) events.
The acceleration is driven by solar flares or
Coronal Mass Ejections.
PAMELA will measure the high energy part of
the proton, electron and helium spectrum during
SEPs, and especially will carry out for the first
time measurements of the positron emission
associated with solar events. These observations are
crucial for understanding the mechanisms of
production and acceleration taking place in the solar
regions.
the dark matter searchsolar events
without the presence of
additional mass. This is
indirect evidence for the
presence of dark matter.
The peripheral stars of
the galaxy M63 rotate
around the center so fast
that they would fly away
A solar flare
on the surface
of the Sun,
as seen by the
TRACE
instrument.
the activity of theWiZard-RIM
collaboration
PAMELA, installed onboard the Russian
Resurs-DK1 spacecraft, was placed into orbit by
a Soyuz rocket.
The launch took place on the 15th June
2006 from the cosmodrome of
Baikonur, in Kazakhstan.
The PAMELA experiment represents
the most important step of the extensive research
program of the international collaboration
WiZard-RIM (Russian Italian Mission),
dedicated to the detection of antimatter and
dark matter signals in space.
As part of this research program, several
balloon-borne experiments (MASS89, MASS91,
TS93, CAPRICE94, CAPRICE98), three experiments
onboard the space station MIR (MARYA-2, SilEye-1
and SilEye-2), and two satellite missions (NINA and
NINA-2) have already been performed between
1989 and 2000.
The PAMELA
Flight Model
integrated into
the satellite
Resurs-DK1
mission details
The TsSKB-Progress
Soyuz rocket
The Resurs-DK1 characteristics are:
Mass: 6.7 tons
Orbit: elliptic
Altitude: 300 - 600 km
Inclination: 70.0°
Lifetime: > 3 years
PAMELA on board has characteristics:
Global Dimensions: 70 x 70 x 120 cm3
Mass: 470 kg
Power Budget: 360 W
The PAMELA
Flight Model
PAMELA will provide results over an unexplored range of energies, with very high statistics. During its three years of
planned operation, the apparatus will:
• measure the proton flux in the energy interval 80 MeV - 700 GeV;
• measure the electron flux in the energy interval 50 MeV - 400 GeV;
• measure the antiproton flux from 80 MeV to 190 GeV;
• measure the positron flux from 50 MeV to 270 GeV;
• identify the electron and proton components up to 10 TeV;
• search for light antinuclei with a sensitivity of the order of 10-8 in the antiHe/He ratio up
to 30 GeV/n;
• measure the light nuclei flux (up to oxygen) from 100 MeV/n to 600 GeV/n;
• study the time and energy distributions of the energetic particles emitted in solar flares
and Coronal Mass Ejections;
• investigate the fluxes of high energy particles in the Earth magnetosphere.
the PAMELA instrument
observational capabilities
th
Silicon Tracker
Time Of Flight System
Neutron Detector
Imaging Calorimeter
Bottom Scintillator
Magnet
Anticoincidence
System
Magne
T
The Time Of Flight System measures the velocity of the particles crossing
the apparatus, and gives the trigger signal for the data acquisition. It comprises 6 layers of
scintillator, two above the CARD, two above the tracker and two above the calorimeter.
The time resolution is of the order of 80 ps for nuclei over a distance of 0.8 m.
The Anticoincidence System is composed by two
sets of scintillators.The primary AC system consists of four plastic scintillators
(CAS) surrounding the sides of the magnet and one covering the top (CAT).
A secondary AC system consists of four plastic scintillators (CARD) that
surround the volume between the first two time-of-flight planes.The
scintillators allow particles entering the tracking system from outside
the geometrical acceptance to be identified.
The Magnetic Spectrometer measures the momentum of the
incident particle, and determines also the sign and the absolute value of the electric
charge. Its core is a Nd-Fe-B permanent magnet divided into five modules which are
interleaved with six frames holding silicon sensors. The Silicon Tracker is composed of 18
ladders of double-sided microstrip detectors arranged on 6 planes.The measured spatial
resolution in the bending view is 4 µm and 15 µm in the non-bending view. The
combined characteristics of the magnet and of the tracker allow a Maximum Detectable
Rigidity (MDR) of about 1200 GV/c to be reached.
The Imaging Calorimeter is able to identify protons and electrons with
an efficiency greater than 90% and a rejection power of 10-4, thank to its capability to
reconstruct the topological and energetic characteristics of the showers which develop
inside its volume. It is composed of 44 silicon layers interleaved with tungsten planes,
each 2.6 mm thick, for a total of 0.6 interaction lengths and 16.3 radiation lengths.
The Bottom Scintillator is located
beneath the calorimeter and is used for triggering the
neutron detector in order to record particles of the
highest energy.
The Neutron Detector,
placed at the bottom of the apparatus,
expands the energy range of the
recorded protons and electrons up to
10 TeV. The signal from this device is used for
the selection of electrons over the proton background,
making use of the different neutron yield coming from
hadronic or electromagnetic showers. It consists of 36 3He counters
enveloped by a polyethylene moderator.
e sub–detectors
etic Spectrometer
Imaging Calorimeter
Neutron Detector
Bottom Scintillator
AnticoincidenceSystem
Time Of Flight system
• University and INFN, Bari (Italy)
• University and INFN, Florence (Italy)
• University and INFN, Naples (Italy)
• University and INFN, Rome “Tor Vergata”, Rome (Italy)
• University and INFN, Trieste (Italy)
• Laboratori Nazionali di Frascati INFN, Frascati (Italy)
• Istituto di Fisica Applicata “Nello Carrara”,Consiglio Nazionale delle Ricerche, Florence (Italy)
the WiZard-RIM collaboration
The mission PAMELA is realized by
an international collaboration of research
institutes, under the responsibility of the
Principal Investigators Prof. P. Picozza
(University and INFN, Rome “Tor Vergata”, Italy)
and Prof. A. Galper (Moscow State Engineering
and Physics Institute, Russia).
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International Program Committee:
Professors P. Carlson (Sweden),
A. Galper (Russia), P. Picozza (Italy),
M. Simon (Germany)
Scientific Coordinator:
Prof. P. Spillantini (Italy)
Technical Coordinator:
Prof. G. Castellini (Italy)
• Moscow State Engineering and Physics Institute, Moscow (Russia)
• Lebedev Physical Institute, Moscow (Russia)
• Ioffe Physical Technical Institute, St. Petersburg (Russia)
• Royal Institute of Technology, Stockholm (Sweden)
• University of Siegen, Siegen (Germany)
• NASA Goddard Space Flight Center, Greenbelt (Usa)
• Particle Astrophysics Laboratory, New Mexico State University,Las Cruces (Usa)
Edited by
Roberta Sparvoli and Vincenzo Buttaro for the WiZard-RIM collaboration.
Figures taken with the courtesy of NASA, ESO, the Stanford-Lockheed ISR, TsSKB-Progress.
Special thanks to Cecilia Migali and Nora Capozio from INFN Communication Office.
For more information about PAMELA and the activities of the WiZard-RIM collaboration, visit the web site: http://wizard.roma2.infn.it.
PAMELA is a mission sponsored by: INFN, RSA, ASI, DLR, RAS, KTH/SNSB.