KISS

Backgrounds

The elements heavier than irons are considered to have been synthesised by the stellar explosion like supernovae. There is no way to directly observe the temperature and neutron density when the explosion happens. However, we can deduce some boundary conditions by investigating the properties of some neutron-rich nuclei since the nucleosynthesis are governed by nuclear reactions.

We focus on the multi-nucleon transfer reaction to produce the neutron-rich nuclei of mass number around 196 which produce the peak in the natural abundance in the elements in the universe.
KISS (KEK Isotope Separation System) is a system which will capture the reaction products with high-flow gas and resonance-ionize them by using the two or three steps lasers. We aim to study the lifetimes and masses of these nuclei in order to unveil the stellar conditions where the nucleosynthesis took place.

HOT NEWS

2015/3/13

KISS will be opened for users from the next RIBF-PAC as one of main apparatuses in RIBF facility. On this opportunity, KISS construction team members would like to grasp that what kind of experiments are expected to be proposed as KISS experiments by which group, well in advance of the official deadline. The purpose is
(1) to provide suggestions to proponents to avoid conflict between experiments being proposed,
(2) to promote improvements of contents based on the knowledge obtained through the KISS development, and
(3) to find out technical developments necessary for performing the experiments.

If you are interested in proposing an experiment using KISS to the future's PAC, please send a brief description of the experiment using the word format (Preproposal_format.docx) to KISS_contact@kek.jp by the April 30th, 2015. Based on this collection, we are willing to start the collaborative discussion with (each of ) you in suitable style. As a reference, please find the present status of KISS appeared in the attached file (KISS_outline.pdf).

Theme

Multi-nucleon transfer reaction

MNT-VAMOS.png

Neutron-rich nuclei whose mass number are around 196 are difficult to produce by fragmentation reaction of U, which are currently one of the powerful ways to produce the neutron-rich nuclei, and thus the alternative production method are being awaited. We adopted the nuclear reactions of around several MeV/nucleon.

At these energies, the reaction energy is far smaller than the fermi-energy which the nucleon in the nucleus has so that the exchange of nucleons between the target and the beam can take place whey they collide. However this reaction needs a lots of parameters to take into account so that there is no reliable theoretical model to describe the reaction. We're going to establish the theory by comparing the experimental cross sections.

Indeed, we performed the measurement of the cross sections for the system of 136Xe and 196Pt using VAMOS sppectrometer at GANIL on March 2012. We're analyzing the data to deduce the systematic cross sections onn the multi-nucleon transfer reaction.

Gascell

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All the reaction products will be stopped in the ultra-high purity Ar gas, and flown to the ionization point by the gas-flow. Design of the gas cell which won't produce the turbulence is the key of the experiment.

Laser Resonance Ionization

Configuration of the electron depends on the number of protons in the nucleus. The transition between the states are accordingly unique to the element. This enables us selectively ionize the atom by shooting the electromagnetic waves of the energy which corresponds to the transition. In the case of the atom, the wavelength are around visible light and they can be provided by using the lasers. At KISS, we provide 2 lasers which are generated by dye-lasers pumped by XeCl-Eximner.

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β-γ-X ray detector

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Presentation / Meeting

International workshop / conference

Domestic workshop / meeting

Reference

  1. Proposal of KISS for International Review is here