d accompanylly, gamma
ays do not
ugh air and
gamma rays.
Electromagnetic radiations of nigh photon energy originating in atomic nuclei a
ing many nuclear reactions (e.9., fission, radioactivity, and neutron capture). Physic
rays are identical with X-rays of high energy; the only essential difference is that Xoriginate from atomic nuclei of high energy. Gamma rays can travel great distances thr
can penetrate considerable thickness of material, although they can neither be seen nor
felt by human
beings except at very high intensities, which cause an itching and tingling sensation o
They can produce harmful effects even at a long distance from their source (The Effects
the skin.
f Nuclear
Weapons, 3rd edition}.
Geiger-Mueller counter. A gas discharge pulse counter for ionizing radiation.
Ton-chamber-type survey meter.
GMT.
ray
See also AN/
R-39 and
Greenwich Mean Time.
{Gy).
A recently introduced ICRP term; 1 Gy equals 100 rad.
ground zero (GZ). The point on the surface of land or water at, or vertically below or abov
of the burst of a nuctear weapon.
the center
gunk.
A viscous commercial preparation that is soluble both in water and petroleum derivativ s.
It acts
as a wetting agent in removing grease and particulate matter from metal and other nonpor us surfaces.
H-13,
U.S. Army helicopter developed for close support with landing-skid-mounted armament.
for Enewetak airlift.
H-19,
Large utility helicopter manufactured by Sikorsky Aircraft Division of United Aircraft Corporation,
Used in CASTLE for Enewetak airlift.
H-hour.
Time zero, or time of detonatian.
When used in connection with planning operations
cific hour on which the operation event commences.
HE.
t is the spe-
See D-day.
half-life. The time required for a radioactive material ta lose half of its radioactivity
Each radionuclide has a unique half-life.
HASL, NYKOPO.
sed in CASTLE
d
Atomic Energy Commission's Health and Safety Laboratory, New York Operations 0
to decay.
ice.
High explosive.
high-altitude burst. Defined, somewhat arbitrarily, as a detonation in or above the stratosp
distribution of the energy of the explosion between blast and thermal radiation changes
with increasing altitude.
re. The
preciably
HMNZS. His (Her) Majesty's New Zealand Ship.
HMR.
Marine Helicopter Transport Squadron.
hodegraph, A common hodograph in meteorology represents the speed and direction of winds at dafferent altitude increments.
hot; hot spot. Commonly used colloquial term meaning a spot or area relatively more radioact ife than some
adjacent area.
HRS-2.
IBDA.
ICRP.
Helicopter manufactured by Sikorsky Aircraft.
Used in CASTLE for Bikini airlift.
Indirect Bomb Damage Assessment. A revised target analysis based on new data such as agtual weapon
yield, burst height, and ground zero obtained by means other than direct assessment.
International Commission on Radiological Protection.
initial radiation.
Also known as prompt radiation.
Electromagnetic radiations of high energ y
Bmitted from
inc ludes
by the
neutrons and gamma rays given off almost instantaneously, as weil as the gamma rays emitt
fission products and other radioactive species in the rising cloud.
Initial radiations f m ground
or near-ground bursts activate both Earth materials and device debris to create contamina fon.
both the firebal! and the radioactive cloud within the first minute after a detonation.
inverse square law. The decrease in radiation intensity with distance from a single-point sou rpe is inproportional to the square of the distance removed.
477