HPS N13.32-2008

$21.45

Performance Testing of Extremity Dosimeters

Published By	Publication Date	Number of Pages
HPS	2008	51

Guaranteed Safe Checkout

Category: HPS

If you have any questions, feel free to reach out to our online customer service team by clicking on the bottom right corner. We’re here to assist you 24/7.
Email:[email protected]

Description

Specifications are given in this standard for test categories,
test irradiation ranges, and acceptable models with associated
levels of performance. A test is conducted when dosimeters are sent
from the facility that normally processes or reads the dosimeters
(i.e., the "processor") to a testing organization that facilitates
the irradiation of the dosimeters under controlled conditions
specified in this standard. The dosimeters are returned to the
processor for evaluation. The results of dosimeter processing are
returned to the testing laboratory for evaluation under the
criteria given in this standard.

The standard applies to dosimetry systems used to assess
personal dose equivalent at a depth of 0.07 mm in ICRU tissue in
extremities, specifically, hands or feet and forearms or legs. As
such, the standard applies to the performance of dosimeters worn on
fingers and on wrists or ankles. Because the basis of the
performance test is the personal dose equivalent at a depth of 0.07
mm, this standard does not apply to dosimeters used to assess the
dose to the lens of the eye or the personal dose equivalent to the
whole body. As in the previous version of this standard, no
consideration is given to administrative aspects of dosimetry
programs such as adequacy of dosimeter identification, detailed
formats of reports, field calibrations, placement of dosimeters on
extremities, or the assessment of dose from the placement of
multiple extremity dosimeters.

The basis of absorbed dose and dose equivalent in this standard
is the personal dose equivalent at 0.07 mm specified in both the
International Commission of Radiological Protection (ICRP) and the
International Commission on Radiation Units and Measurements
(ICRU). Specifically, factors that convert air kerma in photon
fields to personal dose equivalent for rod and pillar phantoms are
given in ISO 4037-3 (ISO 1999).

The standard applies to the evaluation of dosimetry performed
for radiation protection under low-dose and high-dose conditions in
photon and beta fields. The tests for accident dosimetry are
approximately represented by the high-dose category.

As in the earlier standard, N13.32-1995 (ANSI/HPS 1995), neutron
exposure of the extremities still presents a special problem. The
committee reviewed this issue and found no compelling evidence to
implement a neutron dose equivalent test for extremity dosimeters
at this time. Quoting from the previous standard:

Current neutron fluence-to-dose-equivalent conversion factors
specified in recommendations of the NCRP are derived from the
maximum value of dose equivalent in a 30-cm diameter cylindrical
torso phantom. These values include secondary charged particles
from neutron interactions as well as contributions from gamma rays
from the absorption of neutrons by hydrogen atoms. The use of data
(including the quality factors) from the cylindrical torso phantom
model is not applicable for the extremities. Therefore, neutron
test categories are not included in this standard. This issue
should be reexamined in future revisions of this document or when
appropriate fluence-to-dose equivalent conversion factors are
established.

A concerted effort has been made in this standard to segregate
type-testing issues, typically performed once in the lifetime of a
dosimeter system, from periodic performance testing issues. As
such, there is no specific requirement to conduct a one-time
evaluation of dosimeter performance under conditions of
nonperpendicular angular incidence. Neither is there a requirement
to conduct a study to evaluate the lower limit of
detectability.These tests are important in the interpretation of
dosimeter results but should be addressed in a type-testing
standard.

The methodology and criteria presented in this standard provide
the basis for evaluating the performance of extremity dosimeter
systems. Section 2 comprises a list of terms and definitions used
in the standard. Section 3 ANSI/HPS N13.32-2008 2 comprises the
testing procedures, testing categories, specifications of testing
fields, specification of testing phantoms, specification of
irradiation geometries, selection of irradiation levels, and the
assignment of shallow dose equivalent. Section 4 describes the
criteria by which performance is judged to be acceptable.

Following the example set in the standard for testing whole-body
personnel dosimeter systems, N13.11-2001 (ANSI/HPS 2001), ancillary
information to clarify and support the positions in this standard
is included in the appendices.

The scope of this standard is sufficiently comprehensive that
satisfactory performance implies that a dosimetry processor or
provider is competent to assess personal extremity dose under a
broad range of field conditions using the tested dosimetry
system.

Purpose

This standard establishes standardized testing conditions and
criteria to evaluate the performance of personnel extremity
dosimetry services.

Additional information