7 research outputs found
Nuclear structure studies in the A=136 region using transfer reactions
Philosophiae Doctor - PhDThis thesis describes research work undertaken to study neutron pairing correlations
in 136Ba via the 138Ba(p, t) pair transfer reaction and to perform
high-precision spectroscopy of low-lying states in 136Cs using the 138Ba(d, )
reaction. The aim of this project was to provide useful spectroscopic information
relevant for matrix element calculations of 136Xe neutrinoless double
beta decay. This work is relevant because neutrinoless double beta decays
are standard-model-forbidden lepton number violating processes, which if observed,
would establish the Majorana nature of the neutrinos and also determine
the absolute mass scale of the light Majorana neutrinos.
Our experiments show a signi cant fragmentation of the two-neutron transfer
(p, t) strength to excited 0+ states in 136Ba, which could signi cantly affect
future matrix element calculations. Additionally we obtain information on
65 new states in 136Cs observed in this work. It is anticipated that these
new information will play a vital role in improving the precision of calculated
matrix elements for 136Xe double beta decays
Isoscalar giant monopole strength in 58Ni, 90Zr, 120Sn and 208Pb
Inelastic α-particle scattering at energies of a few hundred MeV and very-forward
scattering angles including 0° has been established as a tool for the study of the isoscalar giant
monopole (IS0) strength distributions in nuclei. This compressional mode of nuclear excitation can
be used to derive the incompressibility of nuclear matter. An independent investigation of the IS0 strength in nuclei across a wide mass range was
performed using the 0◦
facility at iThemba Laboratory for Accelerator Based Sciences (iThemba
LABS), South Africa, to understand differences observed between IS0 strength distributions in
previous experiments performed at the Texas A&M University (TAMU) Cyclotron Institute, USA
and the Research Center for Nuclear Physics (RCNP), Japan
Simulation Study of Photon-to-Digital Converter (PDC) Timing Specifications for LoLX Experiment
The Light only Liquid Xenon (LoLX) experiment is a prototype detector aimed
to study liquid xenon (LXe) light properties and various photodetection
technologies. LoLX is also aimed to quantify LXe's time resolution as a
potential scintillator for 10~ps time-of-flight (TOF) PET. Another key goal of
LoLX is to perform a time-based separation of Cerenkov and scintillation
photons for new background rejection methods in LXe experiments. To achieve
this separation, LoLX is set to be equipped with photon-to-digital converters
(PDCs), a photosensor type that provides a timestamp for each observed photon.
To guide the PDC design, we explore requirements for time-based Cerenkov
separation. We use a PDC simulator, whose input is the light information from
the Geant4-based LoLX simulation model, and evaluate the separation quality
against time-to-digital converter (TDC) parameters. Simulation results with TDC
parameters offer possible configurations supporting a good separation. Compared
with the current filter-based approach, simulations show Cerenkov separation
level increases from 54% to 71% when using PDC and time-based separation. With
the current photon time profile of LoLX simulation, the results also show 71%
separation is achievable with just 4 TDCs per PDC. These simulation results
will lead to a specification guide for the PDC as well as expected results to
compare against future PDC-based experimental measurements. In the longer term,
the overall LoLX results will assist large LXe-based experiments and motivate
the assembly of a LXe-based TOF-PET demonstrator system.Comment: 5 pages, 7 figure
Investigation of a light Dark Boson existence: The New JEDI project
International audienceSeveral experiments around the world are looking for a new particle, named Dark Boson, which may do the link between the Ordinary Matter (which forms basically stars, planets, interstellar gas...) and the Hidden Sectors of the Universe. This particle, if it exists, would act as the messenger of a new fundamental interaction of nature. In this paper, the underlying Dark Sectors theory will be introduced first. A non-exhaustive summary of experimental studies carried out to date and foreseen in the incoming years will be presented after,including the 8Be anomaly. The last section will provide a status of the New JEDI**** project which aims to investigate the existence or not of a Dark Boson in the MeV range
Investigation of a light Dark Boson existence: The New JEDI project
International audienceSeveral experiments around the world are looking for a new particle, named Dark Boson, which may do the link between the Ordinary Matter (which forms basically stars, planets, interstellar gas...) and the Hidden Sectors of the Universe. This particle, if it exists, would act as the messenger of a new fundamental interaction of nature. In this paper, the underlying Dark Sectors theory will be introduced first. A non-exhaustive summary of experimental studies carried out to date and foreseen in the incoming years will be presented after,including the 8Be anomaly. The last section will provide a status of the New JEDI**** project which aims to investigate the existence or not of a Dark Boson in the MeV range
Investigation of a light Dark Boson existence: The New JEDI project
International audienceSeveral experiments around the world are looking for a new particle, named Dark Boson, which may do the link between the Ordinary Matter (which forms basically stars, planets, interstellar gas...) and the Hidden Sectors of the Universe. This particle, if it exists, would act as the messenger of a new fundamental interaction of nature. In this paper, the underlying Dark Sectors theory will be introduced first. A non-exhaustive summary of experimental studies carried out to date and foreseen in the incoming years will be presented after,including the 8Be anomaly. The last section will provide a status of the New JEDI**** project which aims to investigate the existence or not of a Dark Boson in the MeV range