Investigations of Electromagnetic Cascades Produced in Lead by 2.5-GeV Bremsstrahlung

Estimation of Absorbed Dose Due to Gas Bremsstrahlung from Electron Storage Rings

“…Recently, some measured results were published, and it is known that the intensity of gas bremsstrahlung is proportional to stored electron beam current and the residual gas pressure in the vacuum chambers (Kobayashi et al 1984;Esposito and Pelliccioni 1986;Hirayama et al 1987). The pressure rise changes almost linearly with beam current ( Kanazawa et al 1987).…”

“…There also are some experimental results about shielding of gas bremsstrahlung ( Esposito and Pelliccioni 1986;DeLuca et al 1987;Hirayama et al 1987; . But it is difficult to know absorbed doses to tissue because the areas of the detectors and photon beams are different in all measurements and there is no secondary-electron equilibrium.…”

“…Bremsstrahlung radiation exits along the beam line which is channeled outside the ring through the shield (Rindi 1982). Gas bremsstrahlung has been measured with various methods at several facilities (Dehne et al 1974;Rindi 1982;Kobayashi et al 1984;Kobayakawa et al 1986;Esposito and Pelliccioni 1986;DeLuca et al 1987;Hirayama et al 1987;Sakanaka et al 1987). It is known that its intensity is high, especially at straight sections ( Esposito and Pelliccioni 1986;DeLuca et al 1987;Ban et al 1987 ) and a narrow beam of bremsstrahlung is seen at the end of the beam line.…”

“…Energy spectra of gas bremsstrahlung were measured at the Photon Factory using 30-cm-long ( 18 radiation lengths) lead-glass shower counters ( Kobayashi et al 1984;Hirayama et al 1987). The cross-sectional area of the counter was 9 X 10 cm2 at the beam entrance and sufficiently larger than the photon beam spot.…”