5 sujets IRFU

Dernière mise à jour : 09-10-2020


• Accelerators physics

• Astrophysics

• Nuclear physics

 

Optimization of the booster for the electron-positron collider FCC-ee

SL-DRF-21-0083

Research field : Accelerators physics
Location :

Département des Accélérateurs, de Cryogénie et de Magnétisme (DACM)

Laboratoire d’Etudes et de Développements pour les Accélérateurs (LEDA)

Saclay

Contact :

Antoine CHANCE

Starting date : 01-11-2020

Contact :

Antoine CHANCE
CEA - DRF/IRFU/DACM/LEDA

(+33) 1 69 08 17 19

Thesis supervisor :

Antoine CHANCE
CEA - DRF/IRFU/DACM/LEDA

(+33) 1 69 08 17 19

Laboratory link : http://irfu.cea.fr/dacm/

More : https://home.cern/science/accelerators/future-circular-collider

Currently, one of the burning questions in particle physics is the understanding of the mass origin of the particles by exploring Higgs properties, more specifically its self-interaction. An electron-positron collider is then a powerful tool for precision physics. In this purpose, the project "Future Circular Collider Innovation Study" (FCCIS) aims to deliver a conceptual report and to give a sustainable implementation long-term plan for a 1OO-km-long electron-antielectron collider at CERN.

The PhD student will join an international collaboration with CERN, DESY, INFN or KIT. The PhD will focus on the booster, the ring which accelerates electrons up to nominal energy before injecting into the collider. The main challenges of the booster are

i) the injection energy. The PhD student will determine the optimum injection energy of the booster ; this choice will have a great impact on the injection complex and its cost

ii) the booster optics. the PhD student will have to explore different optics and propose innovative solutions to improve and boost equilibrium conditions.

iii) the injection into the collider. The PhD student will study how to inject into the ring and will design the transfer lines up to the collider.

The PhD student will use the MAD-X code for the optics calculations, a reference code developed at CERN.
Measuring the growth of massive structures in the distant Universe with deep spectroscopic surveys

SL-DRF-21-0166

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire de Cosmologie et d’Evolution des Galaxies (LCEG)

Saclay

Contact :

Emanuele DADDI

Starting date : 01-10-2021

Contact :

Emanuele DADDI
CEA - DRF/IRFU/DAP/LCEG


Thesis supervisor :

Emanuele DADDI
CEA - DRF/IRFU/DAP/LCEG


Intergalactic magnetic field and gamma ray bursts with CTA

SL-DRF-21-0143

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire d’Etudes des Phénomènes Cosmiques de Haute Energie (LEPCHE)

Saclay

Contact :

Renaud Belmont

Thierry STOLARCZYK

Starting date : 01-09-2021

Contact :

Renaud Belmont
Université de Paris (Paris 7) - DRF/IRFU/DAP/LEPCHE


Thesis supervisor :

Thierry STOLARCZYK
CEA - DRF/IRFU/DAp/LEPCHE

+33 1 69 08 78 12

Personal web page : http://irfu.cea.fr/Pisp/thierry.stolarczyk/

Laboratory link : http://irfu.cea.fr/en/Phocea/Vie_des_labos/Ast/ast_technique.php?id_ast=3709

More : http://www.cta-observatory.org/

The intergalactic magnetic field pervading the cosmic voids is suspected to be a relic field originating from the very first epoch of the cosmic history. The goal of this PhD is to look for signatures of this field in the high-energy data of gamma-ray bursts, and to predict the ability of the future CTA observatory to constrain its properties. This work combines both theoretical modelling and analysis of simulated CTA data.
Characterization of SVOM Gamma-Ray Bursts Afterglows using MXT data

SL-DRF-21-0153

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire des spectro-Imageurs spatiaux (LISIS)

Saclay

Contact :

Diego GOTZ

Starting date : 01-10-2021

Contact :

Diego GOTZ
CEA - DRF/IRFU/DAP/LISIS

+33-1-69-08-59-77

Thesis supervisor :

Diego GOTZ
CEA - DRF/IRFU/DAP/LISIS

+33-1-69-08-59-77

More : http://www.svom.fr

SVOM is a mission dedicated to the detection and characterization of Gamma-Ray Bursts (GRBs) and other multi-messenger sources, and it is scheduled for launch in June 2022.



SVOM carries a unique multi-wavelength payload, sensitive from gamma-rays to the visible band, which is complemented on ground by dedicated wide field and narrow field robotic telescopes, distributed over the entire Earth. The SVOM space segment consists of ECLAIRS, a coded mask telescope operating in the 4-150 keV energy range, GRM, a gamma-ray (20 keV-5 MeV) spectrometer, and two follow-up narrow field telescopes, VT (visible) and MXT (0.2-10 keV). The Microchannel X-ray Telescope (MXT) is a compact and light focusing X-ray telescope. The main goal of MXT is to precisely localize the X-ray counterparts of SVOM GRBs and to study in detail their spectral and temporal characteristics.



Gamma-Ray Bursts are issued either by the collapse of a very massive star (> 50 times the mass of the Sun) or by the coalescence of two compact objects (most likely neutron stars). In both scenari a short lived (less than ~100 s) gamma ray emission is followed by a longer lived (hours to days) X-ray emission, that can provide useful information about the GRB environment, the associated emission processes and, possibly, the nature of the GRB progenitors.



The successful PHD candidate will in first place contribute to the analysis the MXT flight model calibration data obtained in summer 2021 at the PANTER X-ray testing facility. In particular, the PHD student will be in charge of producing the MXT spectral response matrices before the SVOM launch, and of updating them during the first two years of the mission, by analyzing the in-flight calibration data.



The PHD student will be part of the MXT science team, act as a SVOM Burst Advocate, and thanks to this experience and to the deep instrumental knowledge acquired she/he will be able to correctly analyze, since the very beginning of the SVOM mission, X-ray afterglow data, and couple them to the multi wavelength data in order to build a clear phenomenological picture of the SVOM GRBs. In fact, the early GRB afterglow phase is still not fully understood, in particular from the point of view of the contribution of the GRB central engine to the so-called “plateau phases” of the afterglow light curve, whose interpretation could lead to a better understanding of the GRB progenitors.

INVESTIGATION OF THE NUCLEAR TWO-PHOTON DECAY IN SWIFT FULLY STRIPPED HEAVY IONS

SL-DRF-21-0139

Research field : Nuclear physics
Location :

Service de Physique Nucléaire (DPhN)

Laboratoire études du noyau atomique (LENA) (LENA)

Saclay

Contact :

Wolfram KORTEN

Starting date : 01-10-2021

Contact :

Wolfram KORTEN
CEA - DRF/IRFU/DPhN/LENA

+33169084272

Thesis supervisor :

Wolfram KORTEN
CEA - DRF/IRFU/DPhN/LENA

+33169084272

Personal web page : https://www.researchgate.net/profile/Wolfram_Korten

Laboratory link : http://irfu.cea.fr/dphn/Phocea/Vie_des_labos/Ast/ast_sstheme.php?id_ast=293

More : https://www.gsi.de/en/work/research/appamml/atomic_physics/experimental_facilities/esr.htm

The nuclear two-photon, or double-gamma decay is a rare decay mode in atomic nuclei whereby a nucleus in an excited state emits two gamma rays simultaneously. Even-even nuclei with a first excited 0+ state are favorable cases to search for a double-gamma decay branch, since the emission of a single gamma ray is strictly forbidden for 0+ ? 0+ transitions by angular momentum conservation. The double-gamma decay still remains a very small decay branch (<1E-4) competing with the dominant (first-order) decay modes of atomic internal-conversion electrons (ICE) or internal positron-electron (e+-e-) pair creation (IPC). Therefore we will make use of a new technique to search for the double-gamma decay in bare (fully-stripped) ions, which are available at the GSI facility in Darmstadt, Germany. The basic idea of our experiment is to produce, select and store exotic nuclei in their excited 0+ state in the GSI storage ring (ESR). For neutral atoms the excited 0+ state is a rather short-lived isomeric state with a lifetime of the order of a few tens to hundreds of nanoseconds. At relativistic energies available at GSI, however, all ions are fully stripped of their atomic electrons and decay by ICE emission is hence not possible. If the state of interest is located below the pair creation threshold the IPC process is not possible either. Consequently, bare nuclei are trapped in a long-lived isomeric state, which can only decay by double-gamma emission to the ground state. The decay of the isomers would be identified by so-called time-resolved Schottky Mass Spectroscopy. This method allows to distinguish the isomer and the ground state state by their (very slightly) different revolution time in the ESR, and to observe the disappearance of the isomer peak in the mass spectrum with a characteristic decay time. An experiment to search for the double-gamma decay in 72Ge and 70Se has already been accepted by the GSI Programme Committee and should be realised in 2021/22.

 

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