EIA TEP197-A-1997

Introduction

In accordance with the Radiation Control for the Health and
Safety Act of 1968, cathode ray tube (CRT) manufacturers are
required to submit an initial report to the Center for Devices and
Radiological Health (CDRH), an agency of the U.S. Department of
Health and Human Services (DHHS). The initial report for cathode
ray tubes must provide results of the testing and measuring of the
X-radiation emissions from a cathode ray tube.

The initial report for a new CRT tube is submitted by a
manufacturer. The parts of the initial report to be discussed by
this document are the preparation of the data plots for X-radiation
limit curves and 36 pAikg isoexposure-rate limit curves. The
X-radiation limit cuwe defines the relationship between CRT
highvoltage and the X-radiation exposure rate (pNkg) under a
constant beam current. The "36 pNkg isoexposure rate limit curve"
defines the combinations of CRT anode voltages and beam currents
that produce a constant rate, in this case 36 pAikg, of X-radiation
emission from the CRT. Usually, such limit curves represent the
worst case conditions for X-radiation emission from the CRT.
Pertinent parameters to be reported are the registration reference
points and limit curve slope factors.

Throughout this document the terms ''CRT high-voltage" and
"anode voltage" mean the overall acceleration of the electron beam
from cathode to final anode.

Two limit curves should be developed, one for the entire CRT and
one for the anode contact. The following instruction for the
preparation of the X-radiation characteristic curves is recommended
to insure uniformity throughout the CRT industry.

NOTE—TO conform with the International System of Units (SI)
dimensions, the unit for radiation exposure of "pA4g" (picoamperes
per kilogram) has replaced "mWh". The SI equivalent of 0.5 mWh is
36 piükg. The relationship between the two measurements scales
is:

1 mWh = 72 pNkg