携带式数字显示射线探测器—辐射仪
个人核辐射检测仪器
个人射线报警器
环境辐射探测器
放射源探测器
能够装进口袋的射线报警器
辐射仪内容表
辐射仪的特点
是市场上最小、最易使用、高可靠性的GM射线探测电子仪器；
品质高、价实惠、易使用的进口仪器。
液晶显示每分钟的剂量率
显示总照射剂量
理想、小巧、轻便
监查射线现场泄漏与核污染
声光报警
监查环境中的氡污染
可设置报警限度
检查
建筑材料 的放射性
检查
垃圾 与 废料 射线危害
在工厂与实验室中作为个人射线辐射追踪器
检查地下水中的镭射线污染
在反应堆附近检测空气和水是否受放射性污染
检查个人珠宝首饰是否有放射性危害
检查古陶瓷假牙的放射性水平
检查餐具与玻璃器皿的放射性
超平均辐射时有报警信号输出
9V电池（通万用表电池）可连续使用几个月
价格实惠使用简便
在工厂，医院，垃圾处理站，油田，环境检测站等场所，
辐射仪都能给您提供即时的辐射水平数据。它采用充气探头，设计紧凑，适合测量alpha射线，beta射线，gamma射线与X射线。报警限度在出厂时已按国家的有关要求设置。仪器使用9V碱性电池能连续工作２个月以上，并且具有声光报警。重１２５克（包括耐用的ABS外壳，电池，不锈钢夹子，电池），大小为105mm
x 61mm x 22mm 。
辐射仪技术指标
可探测：X-射线.Gamma射线和beta射线
测量范围：0 - 999 mR/hr
GM管 ：0.50英寸. 2.0 - 3.0 mg / 平方厘米的云母窗口
对Cs-137 (660 keV) 的灵敏度：1095 cpm 每
mR/hr
对Co-60灵敏度：1095 cpm 每mR/hr
屏蔽时的最大本底计数 ：< 10 cpm
死时间 ：< 100 毫秒
使用温度：-20 至 55 C
最大高度（海拔）：10,000 英尺
体积 ：61 mm x 105 mm x 22 mm (2.4" x
0.85" x 4.15")
重量 ：125 克（含电池）
身边的放射性与放射性的危害
我们所有的人在日常生活中每天都受到来自地球天然放射性物质、身体内的放射性同位素、太阳和星球等所发出的核辐射射线的照射。这些辐射照射大多数是不可避免的。然而象来自铀矿废料、地下水中溶解的放射性元素（镭盐、氡）、从远处核电站核武器制造工厂和射性废物掩埋场飘过来的放射性粉尘与空气的核辐射射线的照射等，是我们要考虑避免的。放射性元素是不稳定的，它能放出破坏细胞遗传因素的高能带电粒子。有时受损细胞不能自行修复而死掉，有时受损细胞繁殖不受控制而生癌。生物体受到的损害和遗传密码变化的程度取决于射线的能量、原子序数的大小、以及距辐射源的距离。
Nuclear particles are
forcefully ejected by unstable atomic elements, each with its own preferred
method of releasing the overabundance of energy contained in its nucleus. It
first must vibrate itself into the proper pattern. If you were to shake a coin
out of a piggy bank you would succeed only when the coin and the slot were
aligned and moving in the right direction. Although no one can predict when an
individual unstable nucleus of the radioactive atom will give up its excess
energy, the time it takes for half of a large number of these atoms to decay can
be predicted with statistical accuracy. This is know as the half life of the
radioactive element. After ten half life periods have passed, less than a tenth
of one percent of the radiation will remain. Some half-life times are long
enough to require the radioactive source to be isolated from public exposure for
decades, centuries or even millennia.
ALPHA 射线
The excess energy contained in the atom is released in one of a few basic particles and energetic waves. The Greek alphabet is used to name the particles (in the order of their discovery). The alpha particle is the heaviest. It is produced when the heaviest elements decay. The alpha particle contains two neutrons and two protons and leaves the nucleus at around a tenth the speed of light. Its energy is transferred within a short distance to the surrounding media. However, its short flight knocks about 450,0 00 electrons out of the surrounding atoms. The alpha particle emitter will not penetrate the outer layer of our skin, but is dangerous if inhaled or swallowed. The delicate internal workings of the living cell forming the lining of the lungs or internal organs, most certainly will be changed (mutated) or killed outright by the energetic alpha particle. The number of lung cancer cases among uranium miners from inhaled and ingested alpha sources is much higher than those of the public at large. Radon, the gas produced by the decay of radium-226, also emits alpha particles, which poses a hazard to lungs and airways when inhaled. Homes built in areas with high ground radioactivity should be tested for radon buildup in enclosed basement spaces.
BETA 射线
The beta particle is an energetic electron given off by the nucleus of unstable isotopes to restore an energy balance. The Rad*Scanner can detect most energetic beta particles through the case. Weaker beta particles can be detected through the tube window. Although the beta particle is around 8000 times smaller than the alpha particle, it is capable of penetrating much deeper into living matter. Each encounter with a living cell, and there may be many before the beta energy is dissipated, is likely to dam age some of the chemical links between the living molecules of the cell or cause some permanent genetic change in the cell nucleus. If the damage occurs within the generative cells of the ovaries or testes, the damage may be passed to new generations. The normal background radiation level must contribute to the mutation of the gene pool. Most mutations are undesirable with a very few leading to "improvements". Any increase in the background level of radiation should be considered harmful.
GAMMA 射线
The next "particle" is the very high energy "X-ray" called the gamma ray. It is an energetic photon or light wave in the same electromagnetic family as light and x-rays, but is much more energetic and harmful. It is capable of damaging living cells as it slows down by transferring its energy to surrounding cell components. The Rad*Scanner detects energetic gamma rays through the case walls. Gamma ray sources are used to find flaws in pipes and vessels and to check the integrity of welds in steel.
你日常生活中经常接触到的一些射线辐射
夜光手表、老式挂钟和罗盘的含镭数码盘，特别是２０世纪初出产的产品，能放出大量的alpha 射线和gamma 射线，用仪器计数，其计数率超过正常手表的１０倍２０倍甚至更多。一个五十年代生产的台式闹钟，距离其表面１英尺，并且隔一层玻璃，测量的射线竟高达每分钟４０个计数。喜欢珠宝、无盖夜光表和旧胸针饰物等是很危险的，因为含放射性物质的油漆会脱落，容易吸入或吃进身体里面。
从６０年代中开始制造的夜光表用氚（H3,是半衰期为１２年的氢的放射性同位素）或Pm-147(2.64年半衰期的人造放射性同位素)。两种元素都能隔着表盖放射出很多beta和gamma射线。
用煤油汽化的煤汽灯其灯纱含有放射性物质钍。用过的灯纱容易变成粉末，容易进入体内，造成更大的危害。而且，Thorium oxide coated gas lamp
mantles used in ornamental gas lanterns and gas burning camping lamps are
radioactive. The thorium oxide is chosen because it can be raised to white heat
without decomposing. However, the mantle does become extremely fragile and will
powder into a fine ash which can potentially be inhaled or ingested. Thorium is
a natural alpha emitter with the potential for increasing lung tumors. Thorium
disintegrates to produce radon-220, an alpha particle emitting radioactive gas.
Other uses of thorium include improving alloys of tungsten and magnesium.
Thoriated tungsten welding rods are partly vaporized in the arc welding process.
Filaments in electronic tubes and television picture tubes have be coated in
thorium oxides to produce electrons more easily.
Cerium oxide, a powdery
pink glass and jewelry polishing compound, while not radioactive in itself, is
extracted from monazite sands containing thorium oxide. Trace amounts of thorium
oxide remain with the extracted cerium oxide. Thorium oxide is a potent alpha
particle emitter that poses a serious threat to internal organs if inhaled or
ingested.
Most smoke detectors
contain about 1 microcurie of Americium 241, an alpha emitter deposited on a
thin piece of metal foil surrounded by a metal shield. The alpha particles
cannot escape unless the smoke detector is taken apart or vaporized in a fire,
but some gamma rays are emitted. The Rad*Scanner reads about 30 counts per
minute higher than the background average when place on top off a smoke alarm.
The half-life of Am-241 is 458 years and certainly will outlast the useful life
of the smoke detector.
Antistatic brushes for
photographic use in removing dust from film negatives contain Polonium 210, an
alpha emitter that will vaporize appreciably at 55 degrees C (130 degrees F), a
temperature that is reached easily on the dashboard of an automobile on a hot
summer day. This could be another inhalation danger, if the manufacturing method
does not adequately contain the Polonium.
The fluorescent lamp
starters, the small cylindrical package mounted in some types of lighting
fixtures, contains a glass, gas-filled bulb with less than 15 nanocuries of
krypton 85, a beta and gamma emitting radioactive gas with a 10.4 year half
life. The purpose of the krypton is to ionize the other gases in the starter
tube to assist the lamp starting on a cold morning. Actual amounts must be
smaller. The Rad*Scanner has not detected any increase in count levels around
these devices.
Pottery glazes and art
glass, some ceramic glazed jewelry and cloisonné enameled jewelry contain high
percentages of uranium oxides to produce bright yellows and oranges. Fiesta Red
china dishes by Fiestaware produced through 1971 emit gamma and beta. Acidic
foods left in contact with this chinaware will dissolve small amounts of these
radioactive elements which will be ingested. Enameled jewelry made with these
glazes and worn next to the skin is hazardous.
Some gemstones, notably
natural zircons, are radioactive. Additionally, some topaz, beryl and tourmaline
stones were treated with neutrons from atomic reactors to deepen or change their
color. This treatment left some stones hot enough to be of concern, about 0.2
milliroentgens per hour. Some artificial diamonds are made from metal oxides,
such as yttrium oxide stabilized with thorium oxide, a radioactive compound.
Some porcelain teeth,
artificially colored with uranium containing metal oxides to improve the
reflective appearance, can expose the mouth to 1000 millirem per year for each
cap. This is two and a half times the average whole body yearly exposure from
all natural sources and medical X-rays.
Radon, a gaseous breakdown
product of radium, can build up in enclosed spaces such as basements. A potent
alpha emitter, radon is believed to cause as many as 30,000 lung cancer deaths
each year in the United States, alone. The United States Environmental
Protection Agency has mandated some very sophisticated procedures for measuring
trace amounts of radon gas at the levels likely to be found in enclosed spaces.
A known volume of air is forced through a filter and the filter is checked for
radioactive radon breakdown products. If above average count level within
enclosed interior spaces such as basements and ground floor level closets are
detected by the Rad*Scanner, additional approved tests for radon should be done.
Potassium-40, a strong
beta emitter with a long half life of over 1.3 billion years, makes up only a
small proportion (less than 0.02%) of naturally occurring potassium salts. The
long half-life means relatively few atoms of potassium-40 decay at a time. The
total radioactivity is about 1/1000 of an equal weight of uranium salts.
Potassium salt deposits in some places has a higher concentration of
potassium-40. Since potassium is indispensable for life of plants and animals,
we will find it in almost all foods. Some brands of "salt substitute" made
mainly from potassium salts might be marginally more radioactive than others,
depending on the source of the ingredients.
During normal operation,
nuclear power reactor losses from buildup of gasses and easily vaporized
elements are continuously released in small amounts: tritium, iodine, cesium,
krypton and xenon. Of these, the tritium can oxidize to form radioactive water
and organic compounds. Radioactive iodine concentrates in the thyroid gland and
contributes to thyroid malfunctions and tumors. Cesium compounds settle in the
bones. Radioactive krypton and xenon are inert gases that do not readily form
compounds, but are slightly soluble in body fat and decay to form elements that
settle in bone tissue.
天然放射性矿物
Among the representative list of minerals that are radioactive, a number are listed below. These are concentrated enough to be of interest to mining companies. In addition, many areas have dissolved radioactive salts in sub-surface water greatly in excess of environmentally safe limits and must be treated and filtered to specifically remove this hazard.
In some areas of the USA,
mining companies use chemical solutions pumped into the ground to wash out
uranium salts. In the USA alone, a quarter of the drinking water supplies
contain 2000 picocuries per liter of radon gas. Five percent of the domestic
water supplies have radon levels above 10,000 picocuries per liter. Water pumped
from private wells should be tested for radioactivity.
In the process of oil
exploration and recovery, uranium and radium bearing formations are drilled
through and the fluids used to cool and lubricate the drilling bits can be
contaminated. This drilling fluid or "mud" often was left to dry in an open pit.
Insoluble radium compounds can build up or "plate up" to alarming levels on the
pipe.
Over three billion cubic
feet of mine wastes from the uranium and thorium extraction still await proper
disposal. These waste heaps remain about 85% as radioactive as the original ore
from the radioactive breakdown products of uranium and thorium. Thousands of
tons of ore were transported for processing to areas near major population
centers, like Niagara, NY, Salt Lake City, Utah, Cincinnati, Ohio and Chicago,
IL. In some cases, the mining wastes were used to make concrete for buildings
and roads. These m ounds of milling wastes are persistent sources of soluble
radium salts and radon gas.
Some radioactive minerals
collected are:
Autunite, Ca(UO2)2 (PO4)2
. 10-12 H2O, Hydrated calcium uranium phosphate formed as mixed yellow or green
tetragonal platelets that fluoresce bright yellow-green. Cornwall,England; Mount
Pine, North Carolina; Western Colorado; Marysville, Utah; near Spokane,
Washington. Mount Painter, Australia; Autun, France. Novacekite, Mg rich form of
Autunite.
Brannerite, UTi2O6, A
uranium titanate with rare earth and iron oxides varying the composition in
rounded black or brown pebbles and triclinic crystals. Found in W. Custer
County, Idaho; Elliot Lake District, Ontario,Canada; Transvaal, S. Africa.
Carnotite, K2(UO2)2(VO4)2 .
3H2O, A potassium uranium vanadate in sandy or powdery bright yellow masses.
Found in Arizona, Colorado, Nevada, New Mexico, Pennsylvania, Utah in USA;
Elliot Lake, Ontario, Canada; Radium Hill, Australia; Katanga; Mexico.
Monazite, (Ce, La, Yt,
Th)(PO4), Mixed rare earth and thorium phosphates in white, yellow to brown
monoclinic prismatic waxy looking crystals. Found in granite and gneiss
worldwide.
Thorianite, ThO2, Thorium
dioxide in dark grey to black cubic crystals. Found in Easton, Pennsyvania;
Betroka, Madagascar; Balagoda, Sri Lanka. Uranothoranite is a thorium rich
mineral found with thoranite.
Thorite, ThSiO4, Thorium
silicate in yellow-brown to black, tetragonal or pyramidal crystals or masses.
Found in Champlain, New York; Esmark, Norway.
Torbernite, Cu(UO2)2(PO4)2
. 12H2O, A copper uranium phosphate in greenish tabular crystals or scales.
Found in Cornwall, England; New Mexico, Hannibal Mine, S. Dakota; the La Sal
Mountains of Utah, USA; Mount Painter, Australia; Schneeberg, Germany.
Tyuyamunite,
Ca(UO2)2(VO4)2 . 10H2O, A hydrous calcium uranium vanadate in greenish yellow
scales or masses. Found in Montrose County, Colorado, Garfield County, Utah,
USA; Turkestan, USSR.
Uraninite, UO2, Uranium
dioxide in greenish or grayish brown or black cubic crystals or masses also
known as pitchblende or cleveite.
Uranophane or uranotile ,
Ca(UO2)2(Si2O7 . 6H2O, A hydrated calcium uranium silicate in yellow needle-like
crystals or crystaline masses. Found in Mitchell County, N. Carolina, USA;
Silesia, Czechoslovakia; Saxony, Germany.
Zircon, the semi-precious
stone, can be radioactive, even to the extent that it changes crystal structure
over a long period of time.
概念与定义解释
Atomic number - The number of protons in the
nucleus of the atom. Since the protons are positively charged, enough negatively
charged electrons are collected around the nucleus to neutralize or charge
balance the atom. These protons and electrons give the atom its unique chemical
nature.
Atomic mass - The sum of the weights of both the neutrons and the protons in
the atom.
Electron - A small negatively charged particle that surrounds the nucleus
with a mass about 1/1800 that of the proton . Beta particles are energetic
electrons ejected from a radioactive nucleus.
Element - the most basic physical substance composed of all the same type of
atoms. Each atom will have the same number of protons. The number of neutrons
can differ.
Isotope - Atoms with the same number of protons, but differing in the number
of neutrons present in the nucleus. Most elements have more than one isotope.
Neutron - An electrically neutral particle found in the nucleus with a mass
almost that of the proton. In the fission process, neutrons are liberated.
Nucleus - The densely packed kernel of the atom containing protons and
neutrons. The diameter of the nucleus is 100,000 to 200,000 smaller than the
whole atom.
Photon - The smallest unit of light. The photon is often described as a
electromagnetic wave or wave packet. Light photons from red to blue in the
visible spectrum have increasing energy. X-rays and gamma rays are energetic
photons with thousands to millions of times the energy of light photons.
Proton - An electrically positive particle found in the nucleus of the atom.
Each proton is balanced by the charge of an electron surrounding the nucleus.
The electrically neutral atom has the same number of negative electrons as
positive protons.
射线测量的单位
The curie is the number of
particles per second from 1 gram of Radium = 3.7 x 10 E10 counts/second = 37
billion cps. = 37 billion Becquerel.
1 Becquerel (Bq) = 1 count
per second = 1 event per second
1 microcurie = 1 uCi =
37,000 Bq = 37,000 cps.
1 microcurie = 2.22 x
10E6 disintegrations / minute = 2,220,000 cpm.
1 nanocurie = 1 billionth
of a curie = 2,220 disintegrations / minute.
1 picocurie = 2.2
disintegrations / min.
Dosage units:
Gray (Gy) = 1 Joule/kg
Sievert (Sv) = Gray x QF,
where QF is a "quality factor" based on the type of particle.
QF for electrons, positrons, and xrays = 1 QF = 3 to 10 for neutrons,
protons dependent upon the energy transferred by these heavier particles.
QF = 20 for alpha
particles and fission fragments.
The Sievert is a measure
of biological effect.
Converting older units:
1 rad = 1 centigray = 10
milligrays ( 1 rad = 1cGy = 10 mGy )
1 rem = 1 centisievert =
10 millisieverts ( 1 rem = 1cSv = 10 mSv )
1 mrad = 10 uGy
Nominal background
radiation absorbed dose of 100 mrad/year = 1 mGy/yr.
Nominal background
radiation dose biological equivalent of 100mrem/year = 1mSv/yr.
Occupational whole body
limit is 5 rem/yr = 50 mSv/yr. ( Recently proposed that levels be reduced to 2
rem/yr.)
2.5 mrem/hr or 25 uSv/hr
is maximum average working level in industry.
Exposure rate from
Naturally Occurring Radioactive Material (NORM) ; an empirically derived
conversion factor for Ra-226 decay series: 1.82 microR/ hour = 1 picoCurie/gram.
个人剂量限值
在放射实践中，不产生过高的个体照射量，保证任何人的危险度不超过某一数值，即必须保证个人所受的放射性剂量不超过规定的相应限值。ICRP规定工作人员全身均匀照射的年剂量当量限制为50毫希沃特*（mSv），广大居民的年剂量当量限值为1mSv(0.1rem)。我国放射卫生防护基本标准中，对工作人在民年剂量当量限值，采用了ICRP推荐规定的限值，为防止随机效应，规定放射性工作人员受到全身均匀照射时的年剂量当量不应超过50mSv(5rem)，公众中个人受照射的年剂量当量应低于5mSv(0.5rem)。当长期持续受放射性照射时，公众中个人在一生中每年全身受照射的年剂量当量限值不应高于1mSv(0.1rem)，且以上这些限制不包括天然本底照射和医疗照射。
个人剂量限制是强制性的，必须严格遵守。各种民政部下规定的个人剂量限值是不可接受的剂量范围的下界，而不是可以允许接受的剂量上限。即使个人所受剂量没有超过规定的相应的剂量当量限值，仍然必须按照最优化原则考虑是否要进一步降低剂量。所规定的个人剂量限值不能作为达到满意防护的标准或设计指标，只能作为以最优化原则控制照射的一种约束条件而已. 更详细的资料请参考国家环保局(点击进入)列的标准。