Structure and spectroscopy via direct reactions.

Set of 6 telescopes in the reaction chamber of the SPEG area at GANIL (direction of the beam from right to left). [E525S experiment].

Program: Nuclear matter in extreme states /Nuclear structure /  exotic nuclei


The goals of this experimental program is to study the structure of unstable short-lived very-neutron-rich or neutron-deficient nuclei. These nuclei far from the valley of stability are chosen for the (expected) unusual properties: neutron halo, neutron-skin, new shell effects compared to what is known for stable nuclei or close to the stability. This exploration is performed via direct reactions:

-From (p,p') scattering, it is possible to extract the characteristics of the matter density distributions and transition density distributions between the ground and the excited states;

- From transfer reactions the characteristics of the excited states and the overlap between the wave functions of the nuclear states can be discussed, as well as the shell structure configurations of the nuclei.


Set-up of the MUST2 detectors on the base plate of the reaction chamber in the VAMOS area (direction of the beam from right to left).

  Experiments carried out by the group using the SPIRAL beams:

  • E405S (MUST1 SPEG) Spectroscopy of 7,8He ( 8He(p,p') (p,d) (p,t) at 15.6 MeV/nucleon),
  • E422S (VAMOS) Spectroscopy and shell structure of 27Ne (26Ne(d,p)27Ne at 9 MeV/nucleon)

MUST2 campaigns (for which the group was spokesperson and responsible):



Top view of the base plate of the reaction chamber implanted in the BigRIPS area (F8) at RIKEN. The detection setup in the chamber included 8 MUST2 telescopes with one beam detector (PPAC). Another beam detector was settled in front of the chamber.

MUST2 program with the exotic beams of the RIBF facility at RIKEN, produced at high energy (> 200MeV/n).

A campaign  was carried out in 2010 using the MUST2 telescopes at the RIKEN accelerator in Japan. One of the experiment, RIBF57 was done in the F8 area of the BigRIPS line, using the intense exotic beam of 24O. The goal was to investigate the spectroscopy of this N=16 nucleus via the elastic and inelastic scattering on a proton target.  

Spokespersons: CEA Nuclear Physics Department DPhN (SPhN), RIKEN.

  MUST2@RIKEN, (presentation at the scientific council, May 2008).


The experimental campaigns of the MUST2 collaboration and the main publications.




Summary from 2007 till 2017 : summary of the campaigns

At GANIL, the LENA group "Exotic nuclei" was responsible and spokesperson of the campaigns performed in et 2009 and in 2013 using the SPIRAL1 beams (E < 20 MeV/n) and the VAMOS spectrometer. Campaigns of transfer experiments were carried out by the collaboration in the LISE D6 area, during Spring 2014 and in July 2017, with the radioactive beams produced by fragmentation on LISE.

Experimental campaigns and perspectives : cf Exotic nuclei

Program of the MUST2 collaboration and detailed informations on the detector :


Contact :


Last update : 09/26 2017 (4170)

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Structure of exotic nuclei via direct reactions
The structure group of the DPhN conducts experimental studies to determine the structure and reactions of radioactive nuclei far from the valley of stability. These nuclei of short life, unstable, radioactive, are called exotic when they develop unusual structures (large extension of matter, halo or neutron skin, shell structure with new magic numbers). The properties (nuclear size, nucleon shell occupation) can become very different from what is observed for the stable isotope (s).


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