Séminaires de physique corpusculaire
Les séminaires du DPNC ont généralement lieu
les mercredis à 11h15
Auditoire 1S081 - Sciences III - Boulevard d'Yvoy
Organizers : Prof. Giuseppe
Iacobucci & Prof.
Teresa Montaruli
Semestre de Printemps 2013
| Date | Conférencier | Titre du séminaire et Annonce |
06 Fev. |
Prof. Laura Baudis University of Zurich |
Dark matter searches with liquid xenon 
|
| 27 Fev. | Dr Saverio Braccini University of Bern |
The new Bern cyclotron laboratory for PET
radioisotope production and its beam line for multi-disciplinary
research |
| 20 Mar. | Dr Vittorio Boccone Université de Genève |
A new technique in gamma astronomy: an innovative
camera for a high-energy gamma-ray telescope array |
| 24 Avr. | Dr Roberto Cardarelli University Tor Vergata |
Ultra low-noise amplifiers for silicon
and diamond detectors |
| 08 Mai | Dr Francesco Cafagna Bari University & INFN |
The PAMELA mission: more than six years of
Cosmic Rays investigation |
| 15 Mai | Dr Jiri Krepel PSI Paul Scherrer Institut |
Thorium or Uranium fuel cycle for advanced
nuclear reactors? Fuel recycling, multi-recycling, breeding and burning |
| 29 Mai | Dr Mercedes Paniccia Université de Genève |
AMS - First results |
Feb 06: Prof. Laura Baudis, University of Zurich
Title: Dark matter searches with liquid xenon
-
Access to the talk
Abstract: We have strong evidence that about 80% of
matter in our Universe is dark, revealing its presence only by its
gravitational attraction. If the dark matter is made of Weakly Interacting
Massive Particles (WIMPs), it can be directly detected via elastic
scattering from nuclei in ultra-low background, deep underground detectors.
After a brief introduction to the direct detection method, I will
review current techniques based on liquid xenon as target material
to search for these hypothetical particles. The focus will be on recent
results, including those of XENON100, and on the most promising ideas
for the near future.
Feb 27: Dr Saverio Braccini, Albert Einstein Center for Fundamental
Physics, University of Bern
Title: The new Bern cyclotron laboratory for
PET radioisotope production and its beam line for multi-disciplinary
research - Access to the talk
Abstract: The new Bern cyclotron laboratory is based
on a 18 MeV proton cyclotron equipped with a specifically conceived
6 m long research beam line, terminated in a separate bunker. This
particular configuration is designed for industrial Positron Emission
Tomography (PET) radioisotope production as well as for novel detector,
radiation biophysics, radiation protection, materials science, radiochemistry
and radiopharmacy scientific activities. This project is the result
of the successful collaboration among the University Hospital in Bern
(Inselspital), the University of Bern, private investors and industrial
partners. This new facility is now operational and open to national
and international collaborations. The design, the construction, the
commissioning and the first research activities will be presented.
Mar 20: Dr Vittorio Boccone, University of Geneva
Title: A new technique in gamma astronomy: an
innovative camera for a high-energy gamma-ray telescope array - Access
to the talk
Abstract: Solid-state detectors, in particular Geiger-mode
Avalanche Photo-Diodes (G-APDs) represent a valuable alternative to
substitute the Photomultipliers in many applications.
The Cherenkov Telescope Array (CTA) is the first open-access high
energy (HE) gamma ray observatory and consists of many tens of telescopes
of three different sizes (Small, Medium and Large) covering a large
area on the ground.
We proposed a novel design for the Small Size Telescopes of CTA based
on a 4 m Davies Cotton reflector focusing the light on a large area
G-APD (developed by us together with Hamamatsu) array coupled to non-imaging
light concentrators.
I’ll first introduce briefly the physics motivations of CTA with particular
regards to the SST energy range and I’ll then give an overview of
the 4-m DC SST project. I will focus my talk on the R&D necessary
for the design and construction of the G-APD camera that was proposed
by the University of Geneva. I will describe the measurements necessary
to characterize the G-APD and I will discuss and compare our first
results to the design requirements.
April 24: Dr Roberto Cardarelli, University Tor Vergata
Title: Ultra low-noise amplifiers for silicon
and diamond detectors - Access
to the talk
Abstract: Thanks to the SiGe heterojunction, in the last years the
BJT transistor technology has been experiencing a great development
for high frequency and low-noise operation. The performance of an
ultra-low-noise preamplifier (500 e- RMS) with low frequency (100
MHz BW) will be shown. This amplifier, given the low dependence of
the noise from the source capacitance (up to 1 nF), the very fast
rise time (up to 100 ps) and the 50 Ohm input impedance, is particularly
promising for silicon, diamond and high rate gas detectors.
May 08: Dr Francesco Cafagna, Bari University and INFN
Title: The PAMELA mission: more than six years
of Cosmic Rays investigation - Access
to the talk
Abstract: The PAMELA mission major scientific objective is the measurements
of Cosmic Rays energy spectra, with special focus on the antiparticles,
i.e. antiprotons and positrons, ones.
The PAMELA apparatus is a satellite borne magnetic spectrometer and
comprises a time-of-flight system, a silicon-microstrip magnetic spectrometer,
a silicon-tungsten electromagnetic calorimeter, an anticoincidence
system, and shower tail catcher scintillator. It has been more than
six years that the PAMELA mission is taking data in space, on board
of the russian satellite Resurs-DK.
Important results have been obtained on the positron and antiproton
abundance and spectra. Moreover new results have been obtained on
the composition of the charged cosmic radiation that challenge our
current understanding of the mechanisms of production, acceleration
and propagation of cosmic rays in the Galaxy.
In this talk we will review the most recent scientific results obtained
by PAMELA and the apparatus performances during its six year mission.
May 15: Dr Jiri Krepel, PSI Paul Scherrer Institut
Title: Thorium or Uranium fuel cycle for advanced
nuclear reactors? Fuel recycling, multi-recycling, breeding and burning.
- Access to the talk
Abstract: Thorium fuel cycle provides several advantages,
which make it very attractive; e.g. lower waste production and possibly
improved reactor safety. However, there are also some drawbacks if
compared with Uranium cycle. The seminar will provide an overview
of basic physical features of both Thorium and Uranium fuel cycles
and comparison of their performance (criticality, breeding gain) and
safety-related (Doppler effect, coolant density effect) parameters,
with respect to the fuel recycling, multi-recycling, breeding and
burning.
May 29: Dr Mercedes Paniccia, University of Geneva
Title: AMS - First results
Precision measurement of the positron fraction in primary
cosmic rays from 0.5 to 350 GeV with AMS02
The Alpha Magnetic Spectrometer is a state-of-the-art particle physics
detector operating as an external module on the International Space
Station. It uses the unique environment of space to study the universe
and its origin by searching for antimatter, dark matter while performing
precision measurements of cosmic rays composition and flux. Since
its installation on May 19, 2011 it has collected over 30 billion
cosmic rays of energies ranging from several hundred MeV up to few
TeV.
In this talk we will present the precision measurement of the positron
fraction in cosmic rays in the energy range from 0.5 to 350 GeV based
on 6.8 million positron and electron events collected in the initial
18 month period of operation in space.
| Date | Conférencier | Titre du séminaire et Annonce |
| 19 Sep. | Dr Philipp Mertsch University of Oxford & University of Stanford |
From radio halos to Fermi bubbles |
| 26 Sep. | Dr Bill Murray Rutherford Appleton Laboratory (RAL) |
Higgs Boson properties and how to constrain
them |
| 08 Oct. |
Prof. Subir Sarkar University of Oxford |
Alternative to SUSY dark matter |
| 31 Oct. |
Prof. Andrii Neronov, ISDC, Université de Genève | Gamma-ray astronomy in the 100 TeV band
|
| 07 Nov. | Dr Mario Campanelli UCL |
Jet substructure as a tool to reconstruct
the decay of heavy boosted objects |
| 21 Nov. | Prof. Alain Blondel Université de Genève |
Future possibilities for precise studies
of the H(126) Higgs candidate |
| 05 Dec. | Prof. Max Klein University of Liverpool |
Physics and Realisation of the LHeC |
| 12 Dec. | Dr Daniel Muenstermann CERN |
Radiation-hard Active Silicon Sensors
for the ATLAS Upgrade |
| 19 Dec. | Prof. Julien Lesgourges EPFL, Lausanne |
Active and Sterile Neutrinos in Cosmologie
|
Sept. 19: Dr Philipp Mertsch, University of Oxford and Kavli Fellow
at the Kavli Institute of Particle Astrophysics and Cosmology, SLAC,
Stanford University
Title: From radio halos to Fermi bubbles
Diffuse radiation fields pervade the Galaxy from radio waves to gamma-rays
and encode a plenitude of information about non-thermal processes.
For other studies, e.g. dark matter searches, CMB analysis or even
for faint point sources, they constitute an irreducible background
and need to be subtracted off. I will focus on diffuse Galactic emission
in the radio and in gamma-rays describing new ways to understand and
model them. Particular mention will be made of the recently detected
Fermi bubbles and I will suggest a theoretical picture that can explain
both their energy spectrum and morphology.
Sept.
26: Dr. Bill Murray (RAL):
Title: Higgs boson properties and how to constrain them
-Access to the talk
Abstract: The recently-discovered new boson at CERN seems to be a
good candidate for the long-sought Higgs boson. This seminar explores
what we need to learn about it to confirm that it is the Higgs boson
and how we will obtain that information. Some progress should come
rather rapidly at the LHC, but other information will be much harder.
If it is the Higgs boson then its existence at this mass presents
some interesting puzzles, and more detailed measurements may tell
us something about the dark matter binding galaxies together and maybe
the ultimate fate of the Universe.
Oct.
8: Prof. Subir Sarkar (Oxford)
Title: Alternatives to SUSY dark matter
- Access to the talk
Abstract: Much effort has been devoted to the study of weak scale
particles, e.g. supersymmeteric neutralinos, which have a relic abundance
from thermal equilibrium in the early universe of order what is inferred
for dark matter. This does not however provide any connection to the
comparable abundance of baryonic matter, which *must* have a non-thermal
origin. Candidate particles with such a connection are "dark
baryons" with mass of order 10 GeV from a new strongly
interacting sector. Putative signals in experiments such as CoGeNT,
CRESST and DAMA have also focussed attention on such particles. They
can affect heat transport in the Solar interior so as to affect low
energy neutrino fluxes and helio-seismology.
Oct.
31: Prof. Andrii Neronov (ISDC, University of Geneva)
Title: Gamma-ray astronomy in the 100 TeV band
Abstract: Small size telescopes (SST) sub-array of the next-generation
ground-based gamma-ray observatory CTA will extend the energy "window"
available for astronomical observations toward the 100 TeV energy
band. Based on the experience of observations with the current-generation
gamma-ray telescopes, HESS, MAGIC and VERITAS, we have some idea of
what kinds of astronomical sources and what kinds of astrophysical
phenomena we will observe in this new "extremely high energy"
(EHE) band. However, future observations of the sky in the up-to-now
unexplored EHE gamma-ray band might bring some surprising unexpected
discoveries. In this talk I will review the perspectives and challenges
of the new field of EHE gamma-ray astronomy which will be opened by
the SST sub-array of CTA.
Nov.
7: Dr. Mario Campanelli (UCL)
Title: Jet substructure as a tool to reconstruct the decay
of heavy boosted objects - Access
to the talk
Abstract: The LHC is the first collider where particles with mass
at the electroweak scale can be produced with momenta much higher
than their mass. The decay products of these particles are very boosted,
and Hadronic decays would be reconstructed as a single "fat"
jet. In the last few years there has been a great wealth of studies
in the field of hadronic jet substructure to reconstruct these final
states. In this seminar i will review the main phenomenological ideas,
as well as the first experimental results using jet substructure as
a tool to explore new and old physics.
Nov.
21: Prof. Alain Blondel, Université de Genève
Title: Future possibilities for precise studies of the
H(126) Higgs candidate - Access
to the talk
Abstrac: We present a summary of the state-of-the-art comparison relevant
to possible studies of the H(126) Higgs boson candidate. The machines
considered are the LHC and its upgrades, Linear and circular e+e-
colliders such as ILC/CLIC or LEP3/TLEP, gamma-gamma colliders and
muon colliders. The conclusions of the recent ICFA beam dynamics HF2012
workshop in Fermilab will also be shown.
Dec.
5: Prof. Max Klein, University of Liverpool
Title: Physics and Realisation of the LHeC
- Access to the talk
Abstract: The Large Hadron Electron Collider (LHeC) project involves
upgrading the LHC with a new electron beam in order to build a luminous,
TeV energy ep and eA collider at CERN. An introduction is given to
the physics programme of the LHeC, and the design concepts are described
of the 60 GeV electron accelerator and of a new detector for precision
deep inelastic scattering.
Dec.
12: Dr Daniel Muenstermann, CERN
Title: Radiation-hard Active Silicon Sensors for the ATLAS
Upgrade
Abstract: In the coming years, the LHC will be upgraded to provide
much higher luminosity. This implies increased radiation damage, occupany
and pile-up for ATLAS and requires the replacement of the current
Inner Detector with an improved all-silicon Tracker. While the standard
silicon sensor technology appears to be capable of fulfilling the
demanding HL-LHC requirements, new innovative technologies might offer
significant advantages.
Deep-submicron HV CMOS processes feature moderate bulk resistivity
and HV capability and are therefore good candidates for drift-based
radiation-hard monolithic active pixel sensors (MAPS). For the ATLAS
Upgrade, the concept of using a deep-submicron HV CMOS process to
produce a drop-in replacement for traditional radiation-hard silicon
sensors is explored. Unlike fully integrated MAPS, such active sensors
contain simple circuits, e.g. amplifiers and discriminators, but still
require a traditional (pixel or strip) readout chip. This approach
yields most of the advantages of MAPS (improved resolution, reduced
cost and material budget, etc.), without the complication of full
integration on a single chip.
After outlining the design of the HV2FEI4 test ASIC, characterization
results and first experience obtained with pixel and strip readout
will be shown before discussing future prospects of active sensors
and CMOS-based detectors in general.
Dec.
19: Prof. Julien Lesgourges, EPFL, Lausanne
Title: Active and sterile neutrinos in cosmology - Access
to the talk
Abstract: Review of status and prospects for constraining
the neutrino sector using cosmological observables, with an emphasis
on cosmic microwave background and large scale structure data.
Séminaires
exceptionnels - Candidats au poste de MER
Mercredi 18 juillet 2012 dès 08h30 - Auditoire Stückelberg
Ecole de physique, 24, quai Ernest-Ansermet, Genève
--------------------------------------------------
08h30-09h20 :Dr Chiara Casella (ETZH)
- From muon lifetime to positron emission tomography: Scintillators
and photodetectors in precision measurements
The detection of scintillation light produced by ionizing radiation
is certainly one of the oldest and still most widely adopted techniques
in particle physics. Based on my personal experience, I will describe
the experimental concepts and results of two different examples in
this direction: the FAST and the AX-PET experiments.
FAST is a high precision muon lifetime measurement, aiming at a 2
ppm accuracy on the muon lifetime tµ. This is achieved with
a DC p+ beam (170 MeV/c), stopped on a high granularity plastic scintillator
target, viewed by position sensitive photomultipliers (PSPM).
AXPET is a prototype for a novel geometrical concept of positron emission
tomography (PET), based on matrices of LYSO scintillating crystals
read-out by Silicon Photomultipliers (SiPM), for the detection of
511 keV photons. It aims at a high spatial resolution (~ 1 mm3) in
the reconstruction of the photons interaction point.
The working principle and the achieved results of the two experiments
will be described.
09h20-10h10 : Dr Domenico della Volpe (Università di Napoli) - Unfolding the New Physics at LHC
The most recent results on the Higgs discovery with the ATLAS detector
will be presented. The mechanisms to generate the masses of the particle
in the frame of the Standard Model will be first introduced and then
the recents observation will be presented and discussed.
The success of the measurement has depended strongly on the trigger
system, which is fundamental to unfold the interesting physics process
from the huge background from underlying collision events.
As this is is my current area of research activity, I will present
the system's architecture and implementation and discuss the relevance
for the measurement.
10h10-10h40 : Coffee break
10h40-11h30 : Dr Pedro Facal (U. of Chicago) - The microwave technique for the study of the highest energy cosmic rays
The origin and composition of the ultra high energy cosmic rays (UHECRs, those with energies above 1018 eV) have been studied for long. Recent results by the Pierre Auger Observatory, a 3000 square kilometers hybrid detector with unprecedented sensitivity, have shed a light in some of the most pressing questions of the field, like the anisotropy in the arrival directions and the mass composition. But these results show also some of the limitations of the current techniques used for UHECR detection. Recent laboratory measurements suggest that detection of cosmic rays using microwave radiation in the GHz band is possible, and would allow to cover large areas, as needed, with 100% duty cycle and virtually no atmospheric attenuation. I will review the most recent UHECR measurements and present the current efforts towards GHz detection, in particular MIDAS, a prototype radio telescope instrumented with 53 microwave receivers at the University of Chicago.11h30-12h20 : Dr Gerd Pühlhofer (Tübingen University) - Hunting cosmic ray accelerators with TeV observations: Clues from dark TeV sources and Supernova remnants
TeV observations of the Galactic plane hold the promise of identifying
the accelerators of Galactic cosmic rays. Indeed, current Cherenkov
telescopes have found a rich population of Galactic TeV gamma-ray
sources over the past few years. But identifying these gamma-ray sources
with astrophysical objects often turned out to be challenging. I will
report on lessons we learned throughout the identification process,
with a particular emphasis on supernova remnants which are believed
to be the main sources of Galactic cosmic ray particles.
12h20-13h10 : Dr Giulio Saracino (Naples University)
- An application of Silicon Photomultipliers to a tracking detector
for the muon radiography.
Silicon Photomultipliers have been developed about ten years ago and
their use, as an alternative to traditional photomultiplier tubes,
is increasing more and more. They have single photon response capability,
high detection efficiency, high gain at low bias voltage, low power
consumption and very good timing performance. In spite of their Geiger
regime, they can work as linear devices. All these properties motivated
their adoption for a tracker designed for the muon radiography of
volcanoes (muography).
Muography is a novel technique based on the measurement of the absorption
suffered by cosmic muons while traversing the volcano’s edifice.
It can provide a density map of the upper part of a volcano with resolution
better than 100 m. The detector is required to be able to work in
harsh environment and to have low power consumption, good angular
and time resolutions, large active area and modularity.
In this talk I will discuss the main properties of Silicon Photomultiplier
and the design, construction and first measurements of the muon detector
prototype developed for the MU-RAY project.