1965-HKRS30-8-55_Part02 — Page 22

(23 of 1957),

"half-value layer" means the thickness of material which reduces to

half the exposure rate of a particular beam of radiation; "intensity" means the quantity of radiation passing through a unit area perpendicular to the direction of the beam of radiation per unit of time:

"ionometric method" means a method of measurement based on the ionization produced by the radiation which is being measured; "licence" means a licence issued under section 10 of the Ordinance; "licensee”, in relation to any irradiating apparatus, means a person holding a licence for the time being in force issued under the Ordinance with respect to that apparatus;

“maximam permissible dose", in relation to persons employed in radia

tion work, means a dose of radiation-

(a) in the case of skin of the bands, forearms, feet or ankles, of 20 rems in any calendar quarter or 75 rems in any calendar year:

or

(b) in the case of any other parts of the body, of 3 rems in any

calendar quarter or 5 rems in any calendar year;

"medical practitioner" means a medical practitioner for the time being registered or exempted from registration under the Medical Regis tration Ordinance 1957;

"millirad" means one thousandth part of one rad; "millirem" means one thousandth part of one rem; "milliroentgen" means one thousandth part of one roentgen; "panel" means such committee as the Board may from time to time appoint under section 5 of the Ordinance for the purpose of ad- vising the Board upon matters affecting or concerning the state of health of persons employed or to be employed on, or engaged in radiation work;

"photograph" means a photograph of approximate size neither greater than two inches by two and three-quarter inches nor smaller than one and one half inches by two and three-quarter inches; "proximity", in relation to any irradiating apparatus, means a position in which a person may be liable to receive a dose of radiation exceeding 1.5 rems to any part of the body if such position were retained by him for one calendar year:

"quality", in relation to radiation, means the property of the radiation which determines the manner in which it affects and is itself altered by the matter it traverses, expressed quantitatively in terms of equivalent constant potential or half-value layer;

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"rad" means a unit of absorbed dose of energy from radiation which

is equivalent to 100 ergs per gramme of material irradiated; "radiation" and "rays” mean ionizing radiation; "radiation hazard" means the danger to health arising from exposure to ionizing radiation whether such danger is due to radiation arising from sources outside the buman body or to radiation from radioac- tive substances within the body:

"radiation work" means work by any person which involves proximity

to any irradiating apparatus in operation; "roentgen" or "r" means the unit of exposure to X or gamma rays and represents such quantity of X or gamma radiation that the associated corpuscular emission per 0.001293 gramme of air will produce, in air, ions carrying one electrostatic unit of quantity of electricity of either sign:

"rem" means that quantity of radiation which when absorbed by man produces an effect biologically equivalent to the absorption by man of one rad of X-rays with average specific ionization of one hundred ion pairs per micron of water, in terms of its air equivalent, in the same region;

"sealed source" means a radioactive substance which is permanently enclosed in a container in such a manner that it or any part of it cannot be separated from the container unless the container is damaged, but also in such a manner as to permit of the emission of radiation;

"Useful beam" means, in the case of X-rays, that part of the radiation from an X-ray tube that passes through the aperture, cone or other device for collimating the X-ray beam, and, in other cases, any radiations from a sealed source that can be employed for the purposes for which the sealed source is used;

"X-ray machine" means any machine that can be used for the produc-

tion of X-rays.

PART II.

LICENCE.

3. (1) Every application for a licence in accordance with the Application provisions of the Ordinance shall be in Form 1 of the First Schedule, for licence.

First

(2) Each such Form shall be completed and delivered to the Schedule. licensing authority together with the prescribed fee and two copies of a Form 1. photograph of the applicant:

Provided that where a partnership or company is the applicant no photograph shall be required.