Luminescence imaging of helium ions during irradiation to water and to an acrylic block

Although the luminescence images of water and an acrylic block during irradiation of proton and carbon ion beams were measured recently, they were not measured for helium ions. Because the mass of helium ions is four times that of protons and one-third that of carbon ions, different results from protons or carbon ions will be obtained by luminescence imaging. We measured the luminescence images of water and an acrylic block during irradiation of helium ion beams. Imaging was conducted using a cooled charge-coupled device (CCD) camera during the irradiation of helium ion pencil beams at three different energies to a water phantom and an acrylic block in addition to mini-beams of helium ions at four different energies. From the measured luminescence images during irradiation of helium ion pencil beams, we could estimate the ranges of the beams for water and the acrylic block. In the luminescence images of the acrylic block during irradiation of mini-beams of helium ions, we observed the luminescence of mini-beams with Bragg peaks in the images. Luminescence imaging of water and an acrylic block during the irradiation of helium ion beams was possible and could be used for range determination of the beams.