Quantification of pure beta spectra in mixed beta gamma fields as part of eye lens dosimetry at CANDU power plants.

To address the issue of eye lens dosimetry in nuclear industry, we initiated the project to quantify the beta and gamma-ray source term in CANDU power plants and to convert this source term into dosimetric quantities of interest, such as eye lens dose and personal dose equivalents H(10), H(0.07). This way, the eye lens dose can be compared with dosimetric operational quantities to evaluate whether independent dosimetry is required for eye lens protection, or present dosimetry is adequate.

CHARACTERIZATION OF A LANTHANUM BROMIDE DETECTOR FOR EYE LENS DOSIMETRY AT THE CANDU NUCLEAR POWER PLANTS BASED ON DIRECT MEASUREMENTS OF THE GAMMA-RAY SPECTRA.

Gamma-ray spectra were measured using a LaBr$_{3}$(Ce) spectrometer during the outage periods, aiming at quantifying the gamma source term of radiation workers' exposure, at the CANDU nuclear power reactors, for the purposes of eye lens dosimetry. The spectra were measured inside the boiler rooms, of the Bruce Power and Ontario Power Generation (OPG) CANDU nuclear power plants, where workers are exposed to relatively high dose rates radiation fields during the maintenance work. Prior to measurements at the CANDU reactors, the pulse shaping parameters of the gamma spectrometer were optimised for high rates gamma fields, up to an input rates of 120 kcps, in order to accomplish a high output rate with a reasonable energy resolution.

[Risk factors for cerebrovascular stroke in a cohort of hypertensive patients].

Objectives: To identify stroke risk factors in hypertensive patients and the probability of stroke in relation to those risk factors and follow-up.

Study Design: A cohort study (patients with high blood pressure).

Material And Methods: 707 hypertensive patients were studied (Hypertension Register) in what concerns stroke incidence until 1992 (n = 126), considering one case per individual.