Facilities at the Nishina Center

Superconducting Radioactive Isotope Beam Separator (BigRIPS)

A Beam-separating "Dragon"
Image of BigRIPS

The Superconducting Radioactive Isotope Beam Separator (BigRIPS) consists of two sections: the first stage is to separate the RI beam and the second stage is to select particles and transfer them to experimental facilities.Pattern diagram of BigRIPS

Image of Beam-dump
Beam-dump placed in the first stage converts a heavy ion beam into an RI beam.

At the BigRIPS, high-energy stable nuclear beam or uranium beam accelerated at the SRC collide with stable nuclei in a target and then fragment. The high-energy fragments and fragmentation nuclides (RI beam) produced in this interaction are collected with high efficiency using a large-aperture collection system of the first stage. To focus the scattered RI beam, multiple large-aperture superconducting quadrupole triplet electromagnets are used. The BigRIPS adopts a novel technique in that the RI beam that is coarsely separated in the first stage is then accurately separated in the second stage according to the atomic number, charge, mass, and momentum of respective particles, and subsequently delivered to experimental facilities. This unique technique has enabled to produce secondary reactions using rare exotic RI beam for the first time, where either neutrons or protons are extremely dominant.


Beam separation method at the BigRIPS

Pattern diagram of Beam separation method