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RADIATION HAZARDS ABOARD A GUIDED MISSILE CRUISER

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WALTER JOHNSON, VICTOR H. KINDSVATTER, CHRISTOPHER C. SHAW · 1959

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1959 Navy report found no known overexposure of personnel to radar microwave radiation aboard the USS Galveston, while x-rays from its klystron tubes reached 10 roentgens per hour.

Plain English Summary

Summary written for general audiences

This 1959 Navy report examined two radiation problems aboard the USS Galveston, a guided missile cruiser carrying two AN/SPG-49 radar fire-control transmitters: high-power microwave radiation from the radar beams and x-rays from klystron tubes. Radar beams reached 10 milliwatts per square centimeter at distances from 92 feet for one track beam to a calculated 265 feet with all beams on, and to date there had been no known overexposure of personnel to microwave radiation. X-ray intensities reached as high as 10 roentgens per hour at the klystron housing, and temporary lead shielding was installed.

Why This Matters

This 1959 Navy report documents measurements rather than health effects. On the USS Galveston, the radar beams reached 10 milliwatts per square centimeter, the level arbitrarily established as the maximum safe level of microwave radiation for human beings for indefinite periods, at distances from 92 to 265 feet, and personnel were not allowed in the after areas when the transmitters were pointed at them. The report states that to date there had been no known overexposure of personnel to microwave radiation, and none of the men had reported signs or symptoms ascribable to the radar.

The x-rays from the klystron tubes were a separate problem. Intensities as high as 10 roentgens per hour were found, eight men had worked in the area for several weeks before the measurements, and none experienced symptoms of radiation sickness, with follow-up eye examinations negative for cataracts six months later.

Finding

Two separate and distinct radiation problems were found to be associated with the operation of this equipment. One has to do with high-power microwave radiation (radar beam), the other with ionizing radiation (x-ray).

In their words

“Two separate and distinct radiation problems were found to be associated with the operation of this equipment. One has to do with high-power microwave radiation (radar beam), the other with ionizing radiation (x-ray).”

Figures from the Original Paper

Diagram extracted from the original research document.

chartPage 4 - AI-described figure: A chart illustrating the electromagnetic spectrum with wave lengths in Angstrom units and energy in electron volts.
p. 4 of the original PDF
Cite This Study
WALTER JOHNSON, VICTOR H. KINDSVATTER, CHRISTOPHER C. SHAW (1959). RADIATION HAZARDS ABOARD A GUIDED MISSILE CRUISER.
Show BibTeX
@article{radiation_hazards_aboard_a_guided_missile_cruiser_g5643,
  author = {WALTER JOHNSON and VICTOR H. KINDSVATTER and CHRISTOPHER C. SHAW},
  title = {RADIATION HAZARDS ABOARD A GUIDED MISSILE CRUISER},
  year = {1959},
  
  
}
No DOI on file for this study.

Quick Questions About This Study

Two separate radiation problems were found: high-power microwave radiation from the radar beams and ionizing radiation (x-rays) from the klystron tubes. The radar beams reached 10 milliwatts per square centimeter at distances up to a calculated 265 feet, and x-ray intensities were as high as 10 roentgens per hour at the rear of the klystron housing.
Levels above 10 milliwatts per square centimeter are considered hazardous, and the high-power AN/SPG-49 radars produced levels above that in front of the lens and in parts of the after section when pointed at them. In experimental animals, high-intensity radar radiation can cause cataract formation, corneal opacity or testicular degeneration, but to date there had been no known overexposure of personnel.
The distances to the 10 milliwatts per square centimeter level were 92 feet for one track beam, 130 feet for two track beams, 162 feet for one acquisition beam and 230 feet for two acquisition beams, with a calculated estimate of 265 feet for all on simultaneously.
For radar, personnel were not allowed in areas where the AN/SPG-49 transmitters could be pointed at them during activation, and crew members working near the transmitters installed small neon lamps inside their caps, which light at about 5 or 6 milliwatts per square centimeter. For x-rays, temporary additional lead shielding was installed on the klystron, and the report recommended controlled areas, monitoring with film badges or pocket dosimeters, and instruction and periodic physical examinations for personnel.
No, to date there had been no known overexposure of personnel to microwave radiation, and none of the men reported signs or symptoms ascribable to the radar. Some personnel were inadvertently exposed to presumably excessive doses of x-ray before commissioning, but without ill effect, with no symptoms of radiation sickness and negative eye examinations for cataracts six months later.