Missions

The postdoctoral researcher will join the group ASSD in the Astroparticles and Cosmologie
departement of IJCLab, CNRS-Université Paris-Saclay. The group is actively working in the
research of neutrinoless double beta decay with scintillating bolometers. Neutrinoless double
beta decay (0νββ) is a rare nuclear transition which plays a unique role in testing lepton νββ) is a rare nuclear transition which plays a unique role in testing lepton
number violation and in understanding fundamental neutrino properties. It consists in the
transformation of an even-even nucleus into a lighter isobar containing two more protons
and accompanied by the emission of two electrons and no other particle. A promising
experimental approach to study 0νββ) is a rare nuclear transition which plays a unique role in testing lepton νββ is to use the bolometric technique. The postdoctoral
researcher will work in the framework of the CUPID/CROSS programs under the supervision
of Andrea Giuliani. CUPID is a tonne-scale bolometric 0νββ) is a rare nuclear transition which plays a unique role in testing lepton νββ experiment aiming at exploring
the inverted ordering region of the neutrino mass. In order to achieve its science goals,
CUPID aims to increase the source mass and dramatically reduce the backgrounds in the
region of interest with respect to CUORE, the present bolometric experiment. CUPID will
consist of ~150νββ) is a rare nuclear transition which plays a unique role in testing lepton 0νββ) is a rare nuclear transition which plays a unique role in testing lepton Li210νββ) is a rare nuclear transition which plays a unique role in testing lepton 0νββ) is a rare nuclear transition which plays a unique role in testing lepton MoO4 scintillating bolometers, to be installed at the Laboratori
Nazionali del Gran Sasso, LNGS, in Italy. CUPID is now in its construction phase. The postdoc
will be in charge of improving the software to simulate the detector response. This code,
combined with GEANT4 simulations will allow to obtain the projected CUPID backgrounds.
CROSS is an ERC Advanced Grant project started in January 20νββ) is a rare nuclear transition which plays a unique role in testing lepton 18. The key idea is to reject
surface events (the currently dominant background source) by pulse-shape discrimination,
obtained by exploiting solid-state-physics phenomena in superconductors. A dedicated
cryostat have been installed in the Canfranc Underground Laboratory in Spain and the first
phase of CROSS-DEM started in 20νββ) is a rare nuclear transition which plays a unique role in testing lepton 20νββ) is a rare nuclear transition which plays a unique role in testing lepton . The postdoctoral researcher will exploit the data taken
in one of the R&D runs to compare with theoretical models. The resulting parameters will
help in constraining the nuclear models. He/she will use a software based on Bayessian
statistics, already developped by the group.

Activités

The post-doctoral fellow will contribute to :
• the developpement of a software to simulate the response of the CUPID detectors. The
software is expected to be applied to the output of GEANT4 simulations.
• improving the implementation of simulation of the light yield of the scintillating bolometers
• production of the CUPID background projections
• comparison of CROSS data with theoretical models
• publication of one individual and/or joint articles on the above mentioned subjects.

Compétences

Candidates must hold a doctorate in particle physics or astroparticle physic and proven
research skills evidenced by at least one publication as the corresponding author relating to
the subject or activities of the project. Other essential criteria for this position are a sound
knowledge of C++, Python and ROOT. Demonstrable experience in GEANT4 simulations and
ideally knowledge of Bayesian statistics. Sound knowledge in the bolometric detection
technique is also essential. Candidates must have a very positive attitude to working in a
team. Finally, fluency in spoken and written English is a requirement.

Contexte de travail

The Irène Joliot-Curie Physics Laboratory of 2 Infinities (IJCLab) is a UMR under the
supervision of the CNRS (IN2P3), the University of Paris-Saclay and the University of Paris,
located on the campus of the University of Paris -Saclay in Orsay.
IJCLab was born in 2020 from the merger of five units (CSNSM, IMNC, IPN, LAL, LPT). The
personnel is made up of nearly 800 persons, including 120 doctoral students. The research
themes of the laboratory are nuclear physics, high energy physics, theoretical physics,
astroparticle, astrophysics and cosmology, particle accelerators, energy and the
environment and health. IJCLab has very significant technical capacities in all the major fields
required to design, develop / implement the experimental devices necessary for its scientific
activity, as well as the design, development and use of instruments.
The researcher will work in the ASSD group belonging to the Astroparticle and Cosmology
department of the Laboratory. The ASSD group is involved in double beta decay, dark matter
and solid state searches. The group includes around 10 members (permanent staff and
doctoral students). CUPID is an international collaboration with about 180 members from 7
countries, mainly from Italy, US and France.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

Short stays in Italy and US, or in other countries, are expected in the framework of
collaboration meetings or international conferences.