Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yada, Ryuichi*; Maenaka, Kazusuke*; Miyamoto, Shuji*; Okada, Go*; Sasakura, Aki*; Ashida, Motoi*; Adachi, Masashi*; Sato, Tatsuhiko; Wang, T.*; Akasaka, Hiroaki*; et al.
Medical Physics, 47(10), p.5235 - 5249, 2020/10
Times Cited Count:7 Percentile:52.3(Radiology, Nuclear Medicine & Medical Imaging)The dosimeter system is capable of real-time, accurate, and precise measurement under stereotactic body radiation therapy (SBRT) conditions. The probe is smaller than a conventional dosimeter, has excellent spatial resolution, and can be valuable in SBRT with a steep dose distribution over a small field. The developed PSP dosimeter system appears to be suitable for in vivo SBRT dosimetry.
Kurishita, Hiroaki*; Yamamoto, Takuya*; Narui, Minoru*; Yoshitake, Tsunemitsu; Akasaka, Naoaki
JNC TY9400 2004-006, 48 Pages, 2004/04
Radiation embrittlement in high-strength ferritic/martensitic steels of 2WFK and 63WFS and oxide dispersion strengthened (ODS) martensitic steel of H-35 that were irradiated in the experimental fast reactor JOYO is evaluated by instrumented Charpy impact tests for miniaturized (1.5 x 1.5 x 20 mm) and half-sized Charpy V-notch (CVN) specimens. Effects of thermal aging and microstructural evolution during irradiation on radiation embrittlement are described. Next, in order to clarify the specimen size effects on the ductile-to-brittle transition temperature (DBTT) in Charpy impact testing, a method to evaluate the plastic constraint loss for differently sized CVN specimens that may be responsible for the size effects is proposed and applied to 2 WFK. In the method, the constraint factor, a, that is an index of the plastic constraint is defined as a = s*/sy*. Here, s* is the critical cleavage fracture stress which is a material constant and sy* is the uniaxial yield stress at the DBTT at the strain rate generated in the Charpy impact test. The procedures for evaluating each of s* and sy* are described and the result of s* and sy*, thus the value of a, is presented for various types of miniaturized and full-sized CVN specimens of 2 WFK. It is shown that there is the following relationship between a and the specimen size factor, (A*/b2). a=a0-k(A*/b2)0.4 Here, A* is the critical area for cleavage fracture and b is the ligament size. a0 and k are constants depending on a /W (a is the notch depth and W is the specimen width). a increases with increasing a /W.