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17–19 janv. 2018
Santiago de Compostela
Fuseau horaire Europe/Paris

Low-pressure TPC detector for studying photonuclear reactions at astrophysical energies with gamma-ray beams at ELI-NP

18 janv. 2018, 10:00
20m
Aula Magna, Facultad de Física (Santiago de Compostela)

Aula Magna, Facultad de Física

Santiago de Compostela

Facultade de Física. Campus Vida s/n | E-15782, Santiago de Compostela | Galicia, Spain

Orateur

Dr Mikolaj Cwiok (University of Warsaw)

Description

The Extreme Light Infrastructure-Nuclear Physics (ELI-NP) facility will provide monochromatic, high-brilliance and polarized gamma-ray beams, which can be used to study nuclear reactions of current astrophysical interest through the inverse photo-dissociation processes and detailed balance principle. In particular, of special interest are (p, γ) and (α, γ) reactions that regulate the ratio of C and O and those that burn 18O and, therefore, regulate the ratio between 16O and 18O in the Universe. For instance, the benchmark inverse kinematic reaction 12C(γ, α)16O can be investigated down to 1 MeV in the centre-of-mass reference frame, where experimental data from direct experiments are sparse.

A dedicated Time Projection Chamber (ELITPC) with an active gaseous target kept under low pressure is being developed at University of Warsaw, IFIN-HH/ELI-NP and University of Connecticut. The active target volume of ELITPC will be about 35 × 20 × 20 cm3 and will be centered around gamma-beam axis. The reaction products stopped in the gas will produce primary electrons that drift towards charge amplification structures made of Gas Electron Multiplier (GEM) foils. The three-dimensional kinematics of the photo-dissociation events will be reconstructed from about 103 signal strips, arranged into redundant, 3-coordinate system.

High intensity γ beams are expected to be available at ELI-NP (107 photons/bunch, 100 Hz bunch repetition rate). The beam-induced background has been studied using Monte Carlo techniques for different γ beam profiles, in order to optimize the expected signal to background ratio. Several scaled demonstrator detectors were constructed and tested with alpha-particle and X-ray sources.

The results from ongoing R&D activities for this project will be presented.

Author

Dr Mikolaj Cwiok (University of Warsaw)

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