"Performances of the future multidetector PARIS illustrated on the radiative capture physics case"
Dorothée Lebhertz, GANIL, France
(id #148)
Seminar: NoPoster: Yes
Invited talk: No
Exotic compound nuclei at high excitation energy and/or angular momentum de-excite with gamma-ray of high multiplicity in a range of energy between 1 and 50 MeV. This complex gamma-decay is a sensitive probe for the study of collective phenomena and their evolution with temperature and rotation. In order to study such kind of radiation we have to optimize efficiency and resolution. Taking advantage of the recently developed LaBr3 scintillators both characteristic will be obtained. The mutidtetector PARIS [1,2], one of the future SPIRAL2 detectors, will be composed of ~200 modules of pure crystals of LaBr3 or crystals of LaBr3 coupled in a phoswich mode with NaI or CsI scintillators. It will be dedicated to the study of the gamma-radiation of hot nuclei.
An example of the power of PARIS can be illustrated on the radiative capture physics case. The radiative capture, i.e. the complete fusion of projectile and target, cooling only by gamma emission, could be the ideal mechanism to highlight 12C-12C or 12C-16O cluster states predicted by numerous theoretical calculations. The radiative capture process is able to probe, at the same time, the overlap between the entrance channel and states of the composite system and the overlap of these same states with the bound or quasi-bound states. This property can be used to look for the gamma-link between the high deformed cluster bands.
Due to a high Coulomb barrier and a large Q-value the heavy ion radiative capture is a rare process. Nevertheless we measured the full gamma spectrum of the radiative capture using the state of the art 0° spetrometer Dragon and its associated BGO gamma array at Triumf (Vancouver). The data obtained show an important feeding (>50% of the flux) of the doorway states around 10-11 MeV in 24Mg and 28Si [3,4]. A non statistical behavior was found since a single spin in the entrance channel is the best conditions to reproduce the data. Unfortunately the resolution of the BGO array does not allow us to extract the exact number and nature of the intermediate states involved. To be able to conclude, for instance about a cluster behavior, we need to use a gamma spectrometer with higher efficiency and better resolution for gamma-rays between 1 and 25 MeV. These two requests will be fulfilled by the future detector PARIS.
We will first make a short status on the PARIS project, present general performances for a complete array of 200 modules of LaBr3 based on GEANT4 simulations and show the promising results with this multidetector for the radiative capture physics case. In order to get a complete overview of the PARIS possibility we will also present results of simulation for other PARIS physics cases involving large multiplicity in gamma-decay.
.
[1] PARIS Collaboration Website: http://paris.ifj.edu.pl/
[2] A. Maj et al., Acta Phys. Pol. B40 (2009).
[3] D.G. Jenkins et al., Phys.Rev. C 76 (2007) 044310.
[4] D. Lebhertz et al., AIP 1165 (2009) 375
An example of the power of PARIS can be illustrated on the radiative capture physics case. The radiative capture, i.e. the complete fusion of projectile and target, cooling only by gamma emission, could be the ideal mechanism to highlight 12C-12C or 12C-16O cluster states predicted by numerous theoretical calculations. The radiative capture process is able to probe, at the same time, the overlap between the entrance channel and states of the composite system and the overlap of these same states with the bound or quasi-bound states. This property can be used to look for the gamma-link between the high deformed cluster bands.
Due to a high Coulomb barrier and a large Q-value the heavy ion radiative capture is a rare process. Nevertheless we measured the full gamma spectrum of the radiative capture using the state of the art 0° spetrometer Dragon and its associated BGO gamma array at Triumf (Vancouver). The data obtained show an important feeding (>50% of the flux) of the doorway states around 10-11 MeV in 24Mg and 28Si [3,4]. A non statistical behavior was found since a single spin in the entrance channel is the best conditions to reproduce the data. Unfortunately the resolution of the BGO array does not allow us to extract the exact number and nature of the intermediate states involved. To be able to conclude, for instance about a cluster behavior, we need to use a gamma spectrometer with higher efficiency and better resolution for gamma-rays between 1 and 25 MeV. These two requests will be fulfilled by the future detector PARIS.
We will first make a short status on the PARIS project, present general performances for a complete array of 200 modules of LaBr3 based on GEANT4 simulations and show the promising results with this multidetector for the radiative capture physics case. In order to get a complete overview of the PARIS possibility we will also present results of simulation for other PARIS physics cases involving large multiplicity in gamma-decay.
.
[1] PARIS Collaboration Website: http://paris.ifj.edu.pl/
[2] A. Maj et al., Acta Phys. Pol. B40 (2009).
[3] D.G. Jenkins et al., Phys.Rev. C 76 (2007) 044310.
[4] D. Lebhertz et al., AIP 1165 (2009) 375
