Nuclear Techniques ›› 2014, Vol. 37 ›› Issue (10): 100523-100523.

• NUCLEAR PHYSICS, INTERDISCIPLINARY RESEARCH •

### Electron scattering facility for short-lived nuclei at RIKEN

WANG Shuo

1. (Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and Physics, Shandong University, Weihai 264209, China)
• Received:2014-04-28 Revised:2014-06-09 Online:2014-10-10 Published:2014-10-16

Abstract: Background: It has already been confirmed that the SCRIT (Self-Confining Radioactive Isotope Ion Target) method can be used for electron scattering experiment for short-lived nuclei. An electron scattering facility consisting of a microtron type electron accelerator (RTM: Racetrack Microtron), an electron storage ring (SR2: SCRIT-equipped RIKEN Storage Ring) and an ISOL (Isotope Separator Online) involving an RI generator, had already been constructed in 2010 at RIKEN Nishina Center to realize electron scattering experiments for short-lived nuclei with SCRIT technique. Purpose: Ions of stable nuclei, 133Cs and 132Xe, were used as targets to evaluate the performance of this facility. Methods: In the testing experiment, the energy of electron beam was set to 150 MeV. The stored electron beam current was ~200 mA with lifetime ~200 min. To determine the achievable luminosity, elastically scattered electrons were measured by a detection system, which consists of a drift chamber, plastic scintillation detectors and two calorimeters. The trajectories and energies of scattered electrons were determined by the drift chamber and two calorimeters. The detector system covers the scattering angle from 25° to 50°. Results: From the vertex distribution and energy loss in the calorimeters of scattered electrons, the number of elastic scattered electrons from target ions was obtained and the luminosity was determined to be nearly 1027 cm?2?s?1 at beam current 200 mA, which is the required luminosity to determine the charge density distribution of the target nucleus. Conclusion: Except for the RI beam generator, the other parts of SCRIT electron scattering facility have been already constructed. The first experiment for this facility will be elastic electron scattering for short-lived Sn isotopes including a doubly magic nucleus 132Sn in 2015.