0000000000199798
AUTHOR
Hideki Tomita
The laser and optical system for the RIBF-PALIS experiment
Abstract This paper describes the laser and optical system for the Parasitic radioactive isotope (RI) beam production by Laser Ion-Source (PALIS) in the RIKEN fragment separator facility. This system requires an optical path length of 70 m for transporting the laser beam from the laser light source to the place for resonance ionization. To accomplish this, we designed and implemented a simple optical system consisting of several mirrors equipped with compact stepping motor actuators, lenses, beam spot screens and network cameras. The system enables multi-step laser resonance ionization in the gas cell and gas jet via overlap with a diameter of a few millimeters, between the laser photons an…
Development of High Resolution Resonance Ionization Mass Spectrometry for Neutron Dosimetry Technique with93Nb(n,n')93mNb Reaction
We have proposed an advanced technique to measure the 93mNb yield precisely by Resonance Ionization Mass Spectrometry, instead of conventional characteristic X-ray spectroscopy. 93mNb-selective resonance ionization is achievable by distinguishing the hyperfine splitting of the atomic energy levels between 93Nb and 93mNb at high resolution. In advance of 93mNb detection, we could successfully demonstrate high resolution resonant ionization spectroscopy of stable 93Nb using an all solid-state, narrowband and tunable Ti:Sapphire laser system operated at 1 kHz repetition rate. peerReviewed
Development of resonance ionization in a supersonic gas-jet for studies of short-lived and long-lived radioactive nuclei
High-resolution resonance ionization spectroscopy (RIS) is required for laser spectroscopy and trace analysis of short-lived and long-lived radioactive nuclei. We have proposed high-resolution resonance ionization spectroscopy in a gas jet combined with a narrow band-width injection-locked Ti:Sapphire laser. Resonance ionization of stable 93Nb in a gas jet was demonstrated using a broad bandwidth Ti:Sapphire laser. In addition, a setup for high-resolution RIS in a gas-jet was designed using numerical simulations of the gas-jet conditions based on computational fluid dynamics.
Development of two-color resonance ionization scheme for Th using an automated wide-range tunable Ti:sapphire laser system
Two-color resonance ionization schemes of Th were investigated by an automated wide-range tunable, grating-assisted Ti:Sa laser system with intracavity SHG option. A two-color ionization scheme via autoionizing state (1st step: 372.049 nm and 2nd step: 401.031 nm) was developed and its relative efficiency was lower by factor of three compared to a known three color scheme. peerReviewed
Characterization of a pulsed injection-locked Ti:sapphire laser and its application to high resolution resonance ionization spectroscopy of copper
A high repetition rate pulsed Ti:sapphire laser injection-locked to a continuous wave seed source is presented. A spectral linewidth of 20 MHz at an average output power of 4W is demonstrated. An enhanced tuning range from 710-920 nm with a single broadband mirror set is realized by the inclusion of a single thin birefringent quartz plate for suppression of unseeded emission. The spectral properties have been analyzed using both a scanning Fabry-P´erot interferometer as well as crossed beam resonance ionization spectroscopy of the hyperfine levels of natural copper. Delayed ionization of the long-lived excited state is demonstrated for increased resolution. For the excited state hyperfine c…
Development of a sequential data correction method for isotope ratio analysis by resonance ionization mass spectrometry
A sequential data correction method using several experimental parameters of pulsed resonance ionization mass spectrometry was developed to reduce mass discrimination effects for isotope ratio analysis as well as fluctuations in the ion count rate. This correction method was applied to isotope ratio determination of stable titanium isotopes using a two-step, single color ionization scheme. A significant improvement of the precision of the measured isotopic ratio of stable titanium isotopes was demonstrated after correction with a parameter set consisting of laser power, atmospheric pressure, and laser frequency.
Ultra Trace Determination Scheme for26Al by High-Resolution Resonance Ionization Mass Spectrometry using a Pulsed Ti:Sapphire Laser
We propose an ultra trace analysis approach for 26Al by high-resolution Resonance Ionization Mass Spectrometry (RIMS) using a pulsed narrow band-width Ti:Sapphire laser. For ensuring efficient ionization and high isotopic selectivity in RIMS of Al, we developed an injection seeded pulsed Ti:Sapphire laser with high repetition rate operation at up to 10 kHz. The laser produced an output power of 2 W and a spectral band-width of ~20 MHz with a repetition rate of 7 kHz. A first demonstration of its performance was done by detecting stable 27Al using RIMS.
Development of accelerator mass spectrometry assisted by isotope-selective laser photodetachment for monitoring 129I
Abstract A prototype system was developed to investigate an isotope-selective laser photodetachment technique for a 129 I accelerator mass spectrometer. A pulsed ion source for negative iodine ions (I − ) that employed laser ablation proved to be suitable for isotope-selective laser photodetachment. Laser photodetachment of pulsed negative iodine ions was estimated to have an efficiency of about 81% based on a model calculation for the prototype system with a tunable pulsed Ti:sapphire laser.
In-gas-cell laser ionization studies of plutonium isotopes at IGISOL
Abstract In-gas-cell resonance laser ionization has been performed on long-lived isotopes of Pu at the IGISOL facility, Jyvaskyla. This initiates a new programme of research towards high-resolution optical spectroscopy of heavy actinide elements which can be produced in sufficient quantities at research reactors and transported to facilities elsewhere. In this work a new gas cell has been constructed for fast extraction of laser-ionized elements. Samples of 238–240,242 Pu and 244 Pu have been evaporated from Ta filaments, laser ionized, mass separated and delivered to the collinear laser spectroscopy station. Here we report on the performance of the gas cell through studies of the mass spec…