This is original study on design the time-of-flight Rutherford backscattering spectrometry (TOF-RBS) technique for nano-material surface analysis with high resolution. At Fast Neutron Research Facility, FNRF, upgrading of the existing pulsed-beam accelerator from 150-keV of D + to 280 keV of He + was proposed to use for the most powerful method of a near-surface characterizationof materials utilizing TOF-RBS. The beam transport was redesigned based on the new multicusp ion source which was designed the extraction and focusing system for optimization by the computer program KOBRA, and the existing beam pulsing system to provide He + ion beam with a few nano-second width and 280-keV acceleration energy. Simulation was done by the computer program Beam Optics, resulting in the beam size at the target position of 1 mm in diameter. The measured beam size was 6 mm in diameter. The optimization of the target position was done by the PARMELA program,to be at 3.14 m from the middle point of the buncher. Components, beam transport characteristics, beam optic simulation, and role of quadrupole magnet were explained with technical data listed. Design and test of the scattering chamber for TOF-RBS were shown with He-ion scattered spectra which were measured by the MCP detector. The quadrupole triplet was designed and constructed at FNRF. Development of TOF-RBS system was implemented in this study. Designing component, fabrication and installation to the accelerator system were completed. Beam extraction and He-scattering tests were done.

At 150 kV-pulsed neutron generator at the Fast Neutron Researh Facility is being upgraded to produce a 280-kV-pulsed-He beam for Time-of-Flight Rutherford Backscattering Spectrometry (TOF RBS). Modification are being done by replacing the existing beamline elements by a 400-kV accelerating tube, 45o-double focusing dipole magnet and quadrupole lens. The beam transport system has to be redesigned based on the new elements. The important part of a good pulsed beam depends on the pulsing system. The two main parts are the chopper and buncher. Radiofrequency (RF) of 2 MHz is used for the chopper and 4 MHz for the buncher. For the buncher the RF amplitude of 13 kV is applied to two gaps, so that the ion pulse is compressed twice. An optimized geometry for the 280-keV pulsed helium ion beam is presented in this paper,. The PARMELA code has been used to optimize the space-charge effect, resulting in a excitated pulse width of less than 2 ns at a target. The calculated distance from a buncher to the target is 4.6 m. Effects of energy spread and phase angle between the chopper and buncher have been included in the optimization of the bunch lengh.

At 150 kV-pulsed neutron generator at the Fast Neutron Researh Facility is being upgraded to produce a 280-kV-pulsed-He beam for Time-of-Flight Rutherford Backscattering Spectrometry (TOF RBS). Modification are being done by replacing the existing beamline elements by a 400-kV accelerating tube, 45o-double focusing dipole magnet and quadrupole lens. The beam transport system has to be redesigned based on the new elements. The important part of a good pulsed beam depends on the pulsing system. The two main parts are the chopper and buncher. Radiofrequency (RF) of 2 MHz is used for the chopper and 4 MHz for the buncher. For the buncher the RF amplitude of 13 kV is applied to two gaps, so that the ion pulse is compressed twice. An optimized geometry for the 280-keV pulsed helium ion beam is presented in this paper,. The PARMELA code has been used to optimize the space-charge effect, resulting in a excitated pulse width of less than 2 ns at a target. The calculated distance from a buncher to the target is 4.6 m. Effects of energy spread and phase angle between the chopper and buncher have been included in the optimization of the bunch lengh.

At Fast Neutron Research Facility, the 150 kV-pulses neutron generator is being upgraded to a 280-kV-pulse-He beam for time-of-flight Rutherford backscattering spectrometry. It involves replacing the existing beam line elements by a multicusp ion source, a 400-kV accelerating tube, 45o-double focusing dipole magnet and quadrupole lens. The multicusp ion source is a compact filament-driven of 2.6 cm in diameter and 8 cm in length. The current extracted is 20.4 μA with 13 kV of extraction voltage and 8.8 kV of Einzel lens voltage. The beam emittance has found to vary between 6-12 mm mrad. The beam transport system has to be redesigned based on the new elements. The important part of a good pulsed beam depends on the pulsing system. The two main parts are the chopper and buncher. An optimized geometry for the 280 keV pulsed helium ion beam will be presented and discussed. The PARMELA code has been used to optimize the space charge effect, resulting in pulse width of less than 2 ns at a target. The calculated distance from a buncher to the target is 4.6 m. Effects of energy spread and phase angle between chopper and buncher have been included in the optimization of the bunch length.

Because of the limited pulse height energy resolution of a detector, conventional Rutherford backscattering spectrometry (RBS) requires an energy of the incident α particle to be in the MeV region. At Chiang Mai University we have researched the possibility of utilizing a 280 keV nanosecond pulse of helium ions for RBS applications. We have chosen a compact filament-driven multicusp ion source of 2.6 cm in diameter and 8 cm in length being investigated for the time-of-flight RBS applications. In this article, we present the general ion source performance using helium, nitrogen, and argon for generating the discharge plasma. The general ion source characteristics have been measured and analyzed. The measurements also include the extractable ion current and the ion beam emittance. We have performed beam extraction calculations with a computer simulation code KOBRA. Results of the measurements and calculations will be presented and discussed.

A 150-kV, high-current, non-mass-analyzed ion implanter based on a modified duoplasmatron ion source and a completely computerized control has been developed for industrially applicable ion beam surface engineering at Chiang Mai University. High-current (∼mA) N-ion implantation in steels and alloys and other ion beam techniques such as single-ion-beam assisted deposition have been explored using the facility for modification of tribological properties. The ion implanter has been engaged in industrial service to local customers in implanting various practical objects. The ion implantation for both academic and applied purposes has proved to be successful in improving hardness and wear resistance as well as prolonging lifetime of the ion-beam-processed tools.

At Fast Neutron Research Facility, the 150 kV-pulses neutron generator is being upgraded to a 280-kV-pulse-He beam for time-of-flight Rutherford backscattering spectrometry. It involves replacing the existing beam line elements by a multicusp ion source, a 400-kV accelerating tube, 45o-double focusing dipole magnet and quadrupole lens. The multicusp ion source is a compact filament-driven of 2.6 cm in diameter and 8 cm in length. The current extracted is 20.4 μA with 13 kV of extraction voltage and 8.8 kV of Einzel lens voltage. The beam emittance has found to vary between 6-12 mm mrad. The beam transport system has to be redesigned based on the new elements. The important part of a good pulsed beam depends on the pulsing system. The two main parts are the chopper and buncher. An optimized geometry for the 280 keV pulsed helium ion beam will be presented and discussed. The PARMELA code has been used to optimize the space charge effect, resulting in pulse width of less than 2 ns at a target. The calculated distance from a buncher to the target is 4.6 m. Effects of energy spread and phase angle between chopper and buncher have been included in the optimization of the bunch length.