ISO 8529-3:1998 参照中性子線—パート3：面積および個人線量計の校正、およびエネルギーと入射角の関数としての応答の決定 | ページ 6

3.1.1

用量当量

H

[出典: ICRU 51, 1993 ^[6] ]

注記 1線量当量の単位はジュール毎キログラム (J kg ^-1 ) で、特別な名称はシーベルト (Sv) である。

3.1.2

周囲線量当量

H *( 10)

対応する拡張され整列された ICRU 球内の照射野によって生成される放射線照射野内の点における線量当量。整列照射野の方向とは反対の半径上で 10 mm の深さ

注記 1周囲線量当量の単位はジュール毎キログラム (J kg ⁻¹ ) であり、特別な名前はシーベルト (Sv) である。

注記2:拡張され整列されたフィールドでは，フルエンスとそのエネルギー分布は，実際のフィールドでのテスト時点と同じ値を対象ボリューム全体で持ちます。フィールドは単方向です。

3.1.3

個人線量当量

H ( _p )

体の特定の点から 10 mm の深さでの軟部組織における線量当量 (ICRU 51, 1993 ^[6] )

注記 1個人線量当量の単位はジュール毎キログラム (J kg ⁻¹ ) で、特別な名称はシーベルト (Sv) である。

注記 2:レポート 47 ^[5]で、ICRU は個人線量当量の定義に、ICRU 組織の組成を持つファントムの深さdでの線量当量を含めることを検討しました。次に、個人線量計の校正用のH_p (10) は、ICRU 組織 (6.1 を参照) で構成されるファントムの深さ 10 mm での線量当量ですが、校正に使用されるファントムのサイズと形状 (6.2 を参照) です。 2)

3.2.1

influence quantity

quantity that may have a bearing on the result of a measurement without being the subject of the measurement

Note 1 to entry: A list of influence quantities is given in annex A.

3.2.2

reference conditions

represent the set of influence quantity values for which the calibration factor is valid without any correction

[SOURCE: See also the note to 3.2.3.]

Note 1 to entry: The value for the quantity to be measured may be chosen freely in agreement with the properties of the instrument to be calibrated. The quantity to be measured is not an influence quantity (3.2.1) .

3.2.3

standard test conditions

represent the range of values of a set of influence quantities under which a calibration or a determination of the response is carried out

Note 1 to entry: Ideally, calibrations should be carried out under reference conditions. As this is not always achievable or convenient, a (small) interval around the reference values can be used. The deviations of the calibration factor from its value under reference conditions caused by these deviations should in principle be corrected for. In practice, the uncertainty aimed at serves as a criterion: whether the influence quantity has to be taken into account by an explicit correction or whether its effect may be incorporated into the uncertainty. During type tests, all values of influence quantities which are not the subject of the test are fixed within the interval of the standard test conditions. The standard test conditions, together with the reference conditions applicable to this part of ISO 8529, are given in annex A.

3.2.4

calibration conditions

those within the range of standard test conditions actually prevailing during the calibration

3.2.5

point of test

point in the radiation field at which the conventional true value of a quantity (3.2.9) to be measured is known

3.2.6

reference point

point of a dosimeter which is placed at the point of test, for calibration or test purposes

Note 1 to entry: The distance of measurement refers to the distance between the axis of symmetry of the radiation source and the reference point of the dosimeter. For further explanation see 4.1.5.

3.2.7

reference direction

direction in the coordinate system of the dosimeter, with respect to which the angle of the direction of radiation incidence is measured in unidirectional fields

3.2.8

reference orientation

orientation of a dosimeter for which the direction of incident radiation coincides with the reference direction of the dosimeter

3.2.9

conventional true value of a quantity

best estimate of the value of the quantity to be measured, determined by a primary or secondary standard or by a reference instrument that has been calibrated against a primary or secondary standard

Note 1 to entry: A conventional true value is, in general, regarded as being sufficiently close to the true value for the difference to be insignificant for the given purpose.

3.2.10

response

R

quotient of the reading M of a measuring instrument and the conventional true value of the measured quantity

Note 2 to entry: The value of the response may vary with the magnitude of the quantity to be measured. In such cases an instrument is said to be non-linear.

Note 3 to entry: The response R (with respect to fluence or dose equivalent) usually varies with the energy and directional distribution of the incident neutrons. It is, therefore, useful to consider the response as a function of the energy E of incident monoenergetic neutrons and of the direction of incident monodirectional neutrons. R(E) describes the"energy dependence" and the"angle dependence" of the response; for the latter, may be expressed by the angle α between the reference orientation of the device and the direction of an external monodirectional field.

Note 4 to entry: Some evaluation algorithms of multi-element detectors may not be additive, if the dosimeter is irradiated by a combination of radiations of various energies and angles of incidence. For example, if there are two such contributions to the dose equivalent, H₁ and H₂, the sum of the two corresponding readings may differ from the reading caused by a single irradiation with H₁ + H₂, i. e. M_H,1 + M_H,2 ≠ M_{H1 + H2}. In such cases, the function , dealt with in the previous note is not sufficient to characterize the dosimeter in all radiation fields.

3.2.11

calibration

quantitative determination, under a controlled set of standard test conditions, of the reading given by a dosimeter as a function of the value of the quantity to be measured

Note 1 to entry: Normally, the calibration conditions are the full set of standard test conditions (see annex A). A routine calibration can be performed, under simplified conditions, either to check the calibration carried out by the manufacturer or to check whether the calibration factor is sufficiently stable during a continued long-term use of a dosimeter. In general, the methods of a routine calibration will be worked out on the basis of the results of a type test or it may be one of the objectives of a type test, to establish the procedures for a routine calibration in a way that the result of a routine calibration approximates that of a calibration under standard test conditions as closely as possible.

3.2.12

calibration factor

N

conventional true value of the quantity the instrument is intended to measure, divided by the instrument's reading, M (corrected if necessary)

Note 1 to entry: The calibration factor N is dimensionless when the instrument indicates the quantity to be measured. A dosimeter indicating the conventional true value correctly has a calibration factor of unity.

Note 2 to entry: The reciprocal of the calibration factor of a dosimeter is equal to the response under reference conditions. In contrast to the calibration factor which refers to the reference conditions only, the response refers to any conditions prevailing.

Note 3 to entry: The value of the calibration factor may vary with the magnitude of the quantity to be measured. In such cases, the dosimeter is said to have a non-linear response.

3.2.13

normalization

procedure in which the calibration factor is multiplied with a factor in order to achieve, over a certain range of influence quantities, a better estimate of the quantity to be measured

Note 1 to entry: A normalization may be practical when a dosimeter will be used mostly under conditions differing from the reference conditions. In this case, the normalization takes account of differences in response under reference conditions and under conditions of normal operation.