# 56. International Winter Meeting on Nuclear Physics

22-26 January 2018
Bormio, Italy
Europe/Berlin timezone

## Photonuclear astrophysics at ELI-NP

26 Jan 2018, 19:00
20m
Bormio, Italy

#### Bormio, Italy

Short Contribution Nuclear Structure and Astrophysics

### Speaker

Photonuclear reactions at threshold energies are of great interest in nuclear astrophysics. At the Extreme Light Infrastructure - Nuclear Physics (ELI-NP[1]) we are currently developing a new silicon-strip detector array (ELISSA, ELI Silicon Strip Array) to be used with the Gamma Beam System (GBS) that is being installed and will be operational in 2019. The ELI-NP GBS will provide beams in the range between 200 keV and 19.5 MeV with a bandwidth better than 0.5$\%$, spectral density of about 10$^{4}$ photons/(eV·s) and linear polarization higher than 95$\%$. ELISSA is an almost 4$\pi$ array made by 35 Micron X3 position sensitive silicon detectors in a barrel configuration and 8 Micrion QQQ3 double-sided silicon detectors as end-caps, which grant very good energy (better than 1$\%$) and position (1-2mm) resolutions. Such combined performances will allow the measurement of controversial reaction cross-sections, such as $^{12}$C($\alpha$,$\gamma$)$^{16}$O through the inverse $^{16}$O photo-disintegration, $^{24}$Mg($\alpha$,$\gamma$)$^{20}$Ne and many other photodissociation processes relevant to stellar evolution and nucleosynthesis[1]. The physics cases of interest for ELISSA with emphasis of the considered day-one experiments and the results of the tests that were performed so far are discussed. Also, the Monte Carlo tool based on GEANT4[2] and ROOT[3] that is being developed for the study of photonuclear reactions at ELI-NP will be introduced. Finally the results from the simulations performed in order to evaluate the reaction rates, the effects of the straggling of the exit particles due to the thickness of the target and of the resolution of the silicon detectors in photonuclear experiments will be shown. [1] D. Filipescu et al., Eur. Phys. J., A51, 185 (2015).\newline [2] GEANT4: A Simulation toolkit - GEANT4 Collaboration (Agostinelli, S. et al.), Nucl.Instrum.Meth. A506 (2003) 250-303 SLAC-PUB-9350, FERMILAB-PUB-03-339. [3] ROOT - An Object Oriented Data Analysis Framework - Rene Brun and Fons Rademakers, Proceedings AIHENP'96 Workshop, Lausanne, Sep. 1996, Nucl. Inst. \& Meth. in Phys. Res. A 389 (1997) 81-86. See also http://root.cern.ch/.