Development of a wavelength-separated type scintillator with optical fiber (SOF) dosimeter to compensate for the Cerenkov radiation effect.
Bottom Line: A dichroic mirror was used for separating input light signals.Individual signal counting was performed for high- and low-wavelength light signals.Optical fiber bending was also addressed; no bending effect was observed for our wavelength-separated SOF dosimeter.
Affiliation: Department of Medical Physics and Engineering, Graduate School of Medicine, Hokkaido University, N-15 W-7 Kita-ku, Sapporo Hokkaido, 060-8638, Japan firstname.lastname@example.org.Show MeSH
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Mentions: Figure 1 shows the components of our scintillation dosimetry system reported previously . In the succeeding discussion, we refer to this dosimeter as the scintillator with optical fiber (SOF) dosimeter. The scintillator material we used was BC490 plastic manufactured by Saint-Gobain Ltd. BC490 is partially polymerized and hardened by a catalyst, which makes it possible to be tightly attached to the tip of a plastic optical fiber (MH4001 manufactured by Mitsubishi Rayon Co. Ltd, reflective index of 1.49, 1-mm diameter optical fiber with 2.2-mm diameter polyethylene shielding). The plastic scintillator is shaped into a hemisphere with a diameter of 1 mm and an active volume of 0.26 mm3. Hemispherical shape is advantageous for better angular response to the incident radiation. The photon signals are relayed through the optical fiber onto the Photon Counting Head (Hamamatsu H7155), then converted into 30-ns-width TTL pulses. The counting unit is made up of a photomultiplier tube, a charge pre-amplifier and a discriminator. The pulse counts are transmitted to a personal computer via a universal serial bus (USB) connection. The measurable range of the SOF dosimeter, which is from 11.4 cGy min−1 to 1.15 × 104 cGy min−1, covers a range of almost 103 cGy min−1 without switching measurement range .Fig. 1.
Affiliation: Department of Medical Physics and Engineering, Graduate School of Medicine, Hokkaido University, N-15 W-7 Kita-ku, Sapporo Hokkaido, 060-8638, Japan email@example.com.