Ion-trapping properties of SCRIT

Highlights: • SCRIT technique is based on the ion-trapping phenomenon in an electron storage ring. • We investigated an electron beam current dependence of SCRIT ion-trapping properties. • We studied on a time evolution of trapped ions behavior in the SCRIT device. • A lower emittance of a target ion beam is effective collision with an electron beam. • A trapping lifetime depends on electron beam instability, space charge and q/A. -- Abstract: We have developed a novel internal target formation technique, SCRIT (Self-Confining Radioactive-isotope Ion Target) with the aim to achieve electron scattering off unstable nuclei. This technique is based on the ion trapping phenomenon in an electron storage ring. To establish the applicability of SCRIT as a target formation technique, we studied in detail its ion-trapping properties. We focused particularly on the spatial distribution of the trapped target ions and their behavior in time evolution. Over 90% of injected ions were trapped in SCRIT, and the overlap efficiency between the trapped target ion cloud and the electron beam was about 10%. From time evolution measurements and computer simulations, we found that variations in trapping lifetime depending on electron beam instability, space charge effect, and q/A values are crucial to understanding the ion-trapping mechanism of SCRIT