Open-Beam System - hdbk110997

DOE-HDBK-1109-97

Radiological Safety Training for Radiation-Producing (X-Ray) Devices

Student's Guide

The following safety features are specified by ANSI N43.2 for an enclosed-beam

X-ray system:

The sample chamber door or other enclosure should have a fail-safe

interlock on the X-ray tube high-voltage supply or a shutter in the

primary beam so that no X-ray beam can enter the sample chamber while

it is open.

X-ray tube, sample, detector, and analyzing crystal (if used) must be

enclosed in a chamber or coupled chambers that cannot be entered by

any part of the body during normal operation.

Radiation leakage measured at 2 inches (5 cm) from any outer surface

must not exceed 0.25 mrem/hour during normal operation.

(Add facility-specific examples.)

iii.

Open-Beam System.

According to ANSI N43.2, a device that does not meet the enclosed-beam

standards is classified as an open-beam system. In an open-beam system, one or

more X-ray beams are not enclosed, making exposure of human body parts

possible during normal operation. The open-beam system is acceptable for use

only if an enclosed beam is impractical because of any of the following reasons:

A need for frequent changes of attachments and configurations.

A need for making adjustments with the X-ray beam energized.

Motion of specimen and detector over wide angular limits.

The examination of large or bulky samples.