The influence of measurement and storage conditions on alanine ESR dosimeters

✍ Scribed by Antonio Carlos Alexandre; Oswaldo Baffa; Otaciro Rangel Nascimento

• Publisher: Elsevier Science
• Year: 1992
• Weight: 288 KB
• Volume: 43
• Category: Article
• ISSN: 0883-2889
• DOI: 10.1016/0883-2889(92)90017-9

✦ Synopsis

Cylindrical dosimeters were prepared using the weight composition of 80% of oL-alanine (Sigma Co.) and 20% of paraffin as suggested by Bartolotta and Onori (1986). Alanine was dried in vacuum at 40°C. The drying kinetics was followed by weighing the alanine and after 24 h no more changes in weight could be detected. The fine powder was used without any other treatment except drying. Alanine was mixed with fine sieved pure paraffin (melting point 56°C) in a mortar. The dosimeters were made by putting 222 mg of the mixture in a cylindrical stainless steel die having 4.7 mm i.d. and 55 mm height. Two pistons one with a millimetric scale engraved on it, were placed into each end of the matrix opening and the set was inserted in a small laboratory vise for pressing as shown in Fig. 1. The vise was compressed until a length of 11 mm was attained. The dosimeters have a volume of 0.2cm ~ and a density of 1.1 g/cm 3. Dimensions chosen were a compromise of sensitivity (mass), spatial resolution (volume) and the dimensions of the ESR spectrometer resonance cavity.