ABSTRACT
Particle accelerators are often used for both ion implantation and ion beam analysis,
therefore the accurate and precise knowledge of the energies of the accelerated ions is
essential. From the analytical point of view, the energy of the accelerated ion needs to be
known with high precision which can only be achieved through calibration. Ghana Atomic
Energy Commission hosts a 1.7 MV tandem accelerator, at the Accelerator Research
Centre (ARC). This facility uses ion beam techniques such as Proton Induced X-ray
Emission (PIXE) and Rutherford Backscattering Spectrometry (RBS) for elemental
composition analysis of materials to address issues in health, biological, archaeological,
forensic and other areas of science. This study was designed to calibrate the energy of alpha
particle which is mainly used for RBS analysis. The main objective of this study is to
develop a quick, but effective and efficient method for calibrating the 𝛼 (He) beam energies
produced by the Accelerator Research Centre facility for Rutherford Backscattering
Spectrometry. The detector system (Silicon surface barrier detector) for the RBS technique
was also calibrated. The method utilized involved the irradiation of four (4) different
sample (Au, Si, Cu and Al) targets with a Helium beam of known energy to find the offset
in the RBS detector. Americium (241Am) radioactive target with energy 5.486 MeV was
utilized to calibrate the surface barrier detector. Lastly Gold target was irradiated with
helium beam at five (5) different accelerator terminal voltages to complete the system
energy calibration. At the end of the study, an offset parameter of -70.24 was determined
in the channel of the detector system. Detector system constant of 962.8 Channels/MeV
was determined. All these parameters were used as input parameters to calibrate the whole
accelerator system (ion beam energy and detector). The calibration procedure was tested
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against the nuclear resonance method of calibration which is currently utilized at the ARC,
and it was found to be in good agreement with published 27Al(𝛼, 𝛼o)27Al nuclear reaction
resonance data
An efficient and effective accelerator ion beam energy calibration technique has been
successfully adopted and implemented. Although this method is highly efficient, it is also
very simple and cheap. This because only five steps of energy ranges were used during the
processes of the ion beam energy calibration as compared to the several runs of energy
range used in nuclear resonance technique of ion beam energy calibration at the ARC
facility.