Scientific direction Development of key enabling technologies
Transfer of knowledge to industry

PhD : selection by topics

Corpuscular physics and outer space >> Radiation-matter interactions
2 proposition(s).

Sub-ppb detection using graphene nanomechanical resonators with optomechanical transduction

Département Composants Silicium (LETI)

Laboratoire Composants Micro-Capteurs

01-09-2019

SL-DRT-19-0516

thomas.alava@cea.fr

Combining ultimate surface-to-volume ratio, ultra-low mass and elevated Young's modulus, graphene rises as an optimal candidate for the next generation of ultra-low NEMS resonator dedicated to nano-gravimetric sensing. During this Ph.D., a prototype of a resonating graphene NEMS shall be fabricated and applied to mass sensing (being for gas or biological sensing). Current transduction techniques used for silicon NEMS are hardly adaptable to graphene resonators. Hence, the developement of these ultimate physics objects is currently hindered by lack of efficient transduction techniques. We aim, during this Ph.D. , at combining advantages offered by graphene resonator with an optomechanical transduction of its movement, so to demonstrate a sensor with the ability of sensing masses in the Dalton range or gaseous compounds concentration below the ppb limit. These resolutions are currently out-of-reach with current silicon NEMS technology

Measurement of nuclear decay data for beta decay and electron capture using metallic magnetic calorimeters

DM2I (LIST)

Laboratoire de Métrologie de l'Activité

01-09-2019

SL-DRT-19-0643

matias.rodrigues@cea.fr

In the framework of ionizing radiation metrology, one of the tasks of the Laboratoire National Henri Becquerel (LNHB), the French national laboratory for ionizing radiation metrology, is the precise determination of nuclear decay data. During this PhD thesis, cryogenic detectors will be developed for the precise measurement of the shapes of beta spectra, photon emission probabilities and capture probabilities of radionuclides decaying via electron capture. These data are required in various fields of research and application, including nuclear medicine, nuclear energy and waste management, or neutrino physics research. The PhD student will conduct experiments comprising the conception and fabrication of cryogenic detectors, their operation in a complex cryogenic setup, work with highly specific electronics, Monte Carlo simulations, and data analysis using sophisticated methods. The measured data will be compared with theoretical calculations and help to improve nuclear data tables.

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