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nuclide : a type of atom whose nucleus has specific numbers of protons and neutrons | https://openstax.org/books/college-physics-2e/pages/31-glossary |
parent : the original state of nucleus before decay | https://openstax.org/books/college-physics-2e/pages/31-glossary |
photomultiplier : a device that converts light into electrical signals | https://openstax.org/books/college-physics-2e/pages/31-glossary |
positron : the particle that results from positive beta decay; also known as an antielectron | https://openstax.org/books/college-physics-2e/pages/31-glossary |
positron decay : type of beta decay in which a proton is converted to a neutron, releasing a positron and a neutrino | https://openstax.org/books/college-physics-2e/pages/31-glossary |
protons : the positively charged nucleons found in a nucleus | https://openstax.org/books/college-physics-2e/pages/31-glossary |
quantum mechanical tunneling : quantum mechanical effect whereby a particle has a nonzero probability to cross through a potential energy barrier despite not having sufficient energy to pass over the barrier; also called barrier penetration | https://openstax.org/books/college-physics-2e/pages/31-glossary |
radiation detector : a device that is used to detect and track the radiation from a radioactive reaction | https://openstax.org/books/college-physics-2e/pages/31-glossary |
radioactive : a substance or object that emits nuclear radiation | https://openstax.org/books/college-physics-2e/pages/31-glossary |
radioactive dating : an application of radioactive decay in which the age of a material is determined by the amount of radioactivity of a particular type that occurs | https://openstax.org/books/college-physics-2e/pages/31-glossary |
radioactivity : the emission of rays from the nuclei of atoms | https://openstax.org/books/college-physics-2e/pages/31-glossary |
radius of a nucleus : the radius of a nucleus isr=r0A1/3r=r0A1/3 | https://openstax.org/books/college-physics-2e/pages/31-glossary |
range of radiation : the distance that the radiation can travel through a material | https://openstax.org/books/college-physics-2e/pages/31-glossary |
rate of decay : the number of radioactive events per unit time | https://openstax.org/books/college-physics-2e/pages/31-glossary |
scintillators : a radiation detection method that records light produced when radiation interacts with materials | https://openstax.org/books/college-physics-2e/pages/31-glossary |
solid-state radiation detectors : semiconductors fabricated to directly convert incident radiation into electrical current | https://openstax.org/books/college-physics-2e/pages/31-glossary |
tunneling : a quantum mechanical process of potential energy barrier penetration | https://openstax.org/books/college-physics-2e/pages/31-glossary |
Some nuclei are radioactiveâthey spontaneously decay destroying some part of their mass and emitting energetic rays, a process called nuclear radioactivity. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Nuclear radiation, like x rays, is ionizing radiation, because energy sufficient to ionize matter is emitted in each decay. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
The range (or distance traveled in a material) of ionizing radiation is directly related to the charge of the emitted particle and its energy, with greater-charge and lower-energy particles having the shortest ranges. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Radiation detectors are based directly or indirectly upon the ionization created by radiation, as are the effects of radiation on living and inert materials. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Radiation detectors are based directly or indirectly upon the ionization created by radiation, as are the effects of radiation on living and inert materials. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Two particles, both called nucleons, are found inside nuclei. The two types of nucleons are protons and neutrons; they are very similar, except that the proton is positively charged while the neutron is neutral. Some of their characteristics are given inTable 31.2and compared with those of the electron. A mass unit con... | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
A nuclide is a specific combination of protons and neutrons, denoted byZAXNor simplyAX,ZAXNor simplyAX,ZZis the number of protons or atomic number, X is the symbol for the element,NNis the number of neutrons, andAAis the mass number or the total number of protons and neutrons,A=N+Z.A=N+Z. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Nuclides having the sameZZbut differentNNare isotopes of the same element. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
The radius of a nucleus,rr, is approximatelyr=r0A1/3,r=r0A1/3,wherer0=1.2 fmr0=1.2 fm. Nuclear volumes are proportional toAA. There are two nuclear forces, the weak and the strong. Systematics in nuclear stability seen on the chart of the nuclides indicate that there are shell closures in nuclei for values ofZZandNNequ... | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
When a parent nucleus decays, it produces a daughter nucleus following rules and conservation laws. There are three major types of nuclear decay, called alphaα,α,betaβ,β,and gammaγγ. Theααdecay equation isZAXNâZâ2Aâ4YNâ2+24He2.ZAXNâZâ2Aâ4YNâ2+24He2. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Nuclear decay releases an amount of energyEErelated to the mass destroyedÎmÎmbyE=(Îm)c2.E=(Îm)c2. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
There are three forms of beta decay. Theβâβâdecay equation isZAXNâZ+1AYNâ1+βâ+ν¯e.ZAXNâZ+1AYNâ1+βâ+ν¯e. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Theβ+β+decay equation isZAXNâZâ1AYN+1+β++νe.ZAXNâZâ1AYN+1+β++νe. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
The electron capture equation isZAXN+eââZâ1AYN+1+νe.ZAXN+eââZâ1AYN+1+νe. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
βâβâis an electron,β+β+is an antielectron or positron,νeνerepresents an electronâs neutrino, andν¯eν¯eis an electronâs antineutrino. In addition to all previously known conservation laws, two new ones ariseâ conservation of electron family number and conservation of the total number of nucleons. T... | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Half-lifet1/2t1/2is the time in which there is a 50% chance that a nucleus will decay. The number of nucleiNNas a function of time isN=N0eâλt,N=N0eâλt,whereN0N0is the number present att=0t=0, andλλis the decay constant, related to the half-life byλ=0.693t1/2.λ=0.693t1/2. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
One of the applications of radioactive decay is radioactive dating, in which the age of a material is determined by the amount of radioactive decay that occurs. The rate of decay is called the activityRR:R=ÎNÎt.R=ÎNÎt. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
The SI unit forRRis the becquerel (Bq), defined by1 Bq=1 decay/s.1 Bq=1 decay/s. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
RRis also expressed in terms of curies (Ci), where1Ci=3.70Ã1010Bq.1Ci=3.70Ã1010Bq. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
The activityRRof a source is related toNNandt1/2t1/2byR=0.693Nt1/2.R=0.693Nt1/2. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
SinceNNhas an exponential behavior as in the equationN=N0eâλtN=N0eâλt, the activity also has an exponential behavior, given byR=R0eâλt,R=R0eâλt,whereR0R0is the activity att=0t=0. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
The binding energy (BE) of a nucleus is the energy needed to separate it into individual protons and neutrons. In terms of atomic masses,BE={[Zm(1H)+Nmn]âm(AX)}c2,BE={[Zm(1H)+Nmn]âm(AX)}c2,wherem1Hm1His the mass of a hydrogen atom,mAXmAXis the atomic mass of the nuclide, andmnmnis the mass of a neutron. Patterns in... | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Tunneling is a quantum mechanical process of potential energy barrier penetration. The concept was first applied to explainααdecay, but tunneling is found to occur in other quantum mechanical systems. | https://openstax.org/books/college-physics-2e/pages/31-section-summary |
Anger camera : a common medical imaging device that uses a scintillator connected to a series of photomultipliers | https://openstax.org/books/college-physics-2e/pages/32-glossary |
break-even : when fusion power produced equals the heating power input | https://openstax.org/books/college-physics-2e/pages/32-glossary |
breeder reactors : reactors that are designed specifically to make plutonium | https://openstax.org/books/college-physics-2e/pages/32-glossary |
breeding : reaction process that produces239Pu | https://openstax.org/books/college-physics-2e/pages/32-glossary |
critical mass : minimum amount necessary for self-sustained fission of a given nuclide | https://openstax.org/books/college-physics-2e/pages/32-glossary |
criticality : condition in which a chain reaction easily becomes self-sustaining | https://openstax.org/books/college-physics-2e/pages/32-glossary |
fission fragments : a daughter nuclei | https://openstax.org/books/college-physics-2e/pages/32-glossary |
food irradiation : treatment of food with ionizing radiation | https://openstax.org/books/college-physics-2e/pages/32-glossary |
free radicals : ions with unstable oxygen- or hydrogen-containing molecules | https://openstax.org/books/college-physics-2e/pages/32-glossary |
gamma camera : another name for an Anger camera | https://openstax.org/books/college-physics-2e/pages/32-glossary |
gray (Gy) : the SI unit for radiation dose which is defined to be1 Gy=1 J/kg=100 rad1 Gy=1 J/kg=100 rad | https://openstax.org/books/college-physics-2e/pages/32-glossary |
high dose : a dose greater than 1 Sv (100 rem) | https://openstax.org/books/college-physics-2e/pages/32-glossary |
hormesis : a term used to describe generally favorable biological responses to low exposures of toxins or radiation | https://openstax.org/books/college-physics-2e/pages/32-glossary |
ignition : when a fusion reaction produces enough energy to be self-sustaining after external energy input is cut off | https://openstax.org/books/college-physics-2e/pages/32-glossary |
inertial confinement : a technique that aims multiple lasers at tiny fuel pellets evaporating and crushing them to high density | https://openstax.org/books/college-physics-2e/pages/32-glossary |
linear hypothesis : assumption that risk is directly proportional to risk from high doses | https://openstax.org/books/college-physics-2e/pages/32-glossary |
liquid drop model : a model of nucleus (only to understand some of its features) in which nucleons in a nucleus act like atoms in a drop | https://openstax.org/books/college-physics-2e/pages/32-glossary |
low dose : a dose less than 100 mSv (10 rem) | https://openstax.org/books/college-physics-2e/pages/32-glossary |
magnetic confinement : a technique in which charged particles are trapped in a small region because of difficulty in crossing magnetic field lines | https://openstax.org/books/college-physics-2e/pages/32-glossary |
moderate dose : a dose from 0.1 Sv to 1 Sv (10 to 100 rem) | https://openstax.org/books/college-physics-2e/pages/32-glossary |
neutron-induced fission : fission that is initiated after the absorption of neutron | https://openstax.org/books/college-physics-2e/pages/32-glossary |
nuclear fission : reaction in which a nucleus splits | https://openstax.org/books/college-physics-2e/pages/32-glossary |
nuclear fusion : a reaction in which two nuclei are combined, or fused, to form a larger nucleus | https://openstax.org/books/college-physics-2e/pages/32-glossary |
positron emission tomography (PET) : tomography technique that usesβ+β+emitters and detects the two annihilationγγrays, aiding in source localization | https://openstax.org/books/college-physics-2e/pages/32-glossary |
proton-proton cycle : the combined reactions1H+1Hâ2H+e++ve,1H+2Hâ3He+γ, and3He+3Heâ4He+1H+1H | https://openstax.org/books/college-physics-2e/pages/32-glossary |
quality factor : same as relative biological effectiveness | https://openstax.org/books/college-physics-2e/pages/32-glossary |
rad : the ionizing energy deposited per kilogram of tissue | https://openstax.org/books/college-physics-2e/pages/32-glossary |
radiolytic products : compounds produced due to chemical reactions of free radicals | https://openstax.org/books/college-physics-2e/pages/32-glossary |
radiopharmaceutical : compound used for medical imaging | https://openstax.org/books/college-physics-2e/pages/32-glossary |
radiotherapy : the use of ionizing radiation to treat ailments | https://openstax.org/books/college-physics-2e/pages/32-glossary |
relative biological effectiveness (RBE) : a number that expresses the relative amount of damage that a fixed amount of ionizing radiation of a given type can inflict on biological tissues | https://openstax.org/books/college-physics-2e/pages/32-glossary |
roentgen equivalent man (rem) : a dose unit more closely related to effects in biological tissue | https://openstax.org/books/college-physics-2e/pages/32-glossary |
shielding : a technique to limit radiation exposure | https://openstax.org/books/college-physics-2e/pages/32-glossary |
sievert : the SI equivalent of the rem | https://openstax.org/books/college-physics-2e/pages/32-glossary |
single-photon-emission computed tomography (SPECT) : tomography performed withγγ-emitting radiopharmaceuticals | https://openstax.org/books/college-physics-2e/pages/32-glossary |
supercriticality : an exponential increase in fissions | https://openstax.org/books/college-physics-2e/pages/32-glossary |
tagged : process of attaching a radioactive substance to a chemical compound | https://openstax.org/books/college-physics-2e/pages/32-glossary |
therapeutic ratio : the ratio of abnormal cells killed to normal cells killed | https://openstax.org/books/college-physics-2e/pages/32-glossary |
Radiopharmaceuticals are compounds that are used for medical imaging and therapeutics. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
The process of attaching a radioactive substance is called tagging. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Table 32.1lists certain diagnostic uses of radiopharmaceuticals including the isotope and activity typically used in diagnostics. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
One common imaging device is the Anger camera, which consists of a lead collimator, radiation detectors, and an analysis computer. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Tomography performed withγγ-emitting radiopharmaceuticals is called SPECT and has the advantages of x-ray CT scans coupled with organ- and function-specific drugs. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
PET is a similar technique that usesβ+β+emitters and detects the two annihilationγγrays, which aid to localize the source. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
The biological effects of ionizing radiation are due to two effects it has on cells: interference with cell reproduction, and destruction of cell function. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
A radiation dose unit called the rad is defined in terms of the ionizing energy deposited per kilogram of tissue:1 rad=0.01 J/kg.1 rad=0.01 J/kg. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
The SI unit for radiation dose is the gray(Gy), which is defined to be1 Gy = 1 J/kg = 100 rad.1 Gy = 1 J/kg = 100 rad. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
To account for the effect of the type of particle creating the ionization, we use the relative biological effectiveness (RBE) or quality factor (QF) given inTable 32.2and define a unit called the roentgen equivalent man (rem) asrem=radÃRBE.rem=radÃRBE. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Particles that have short ranges or create large ionization densities have RBEs greater than unity. The SI equivalent of the rem is the sievert (Sv), defined to beSv=GyÃRBEand 1 Sv=100 rem.Sv=GyÃRBEand 1 Sv=100 rem. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Whole-body, single-exposure doses of 0.1 Sv or less are low doses while those of 0.1 to 1 Sv are moderate, and those over 1 Sv are high doses. Some immediate radiation effects are given inTable 32.4. Effects due to low doses are not observed, but their risk is assumed to be directly proportional to those of high doses,... | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Radiotherapy is the use of ionizing radiation to treat ailments, now limited to cancer therapy. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
The sensitivity of cancer cells to radiation enhances the ratio of cancer cells killed to normal cells killed, which is called the therapeutic ratio. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Doses for various organs are limited by the tolerance of normal tissue for radiation. Treatment is localized in one region of the body and spread out in time. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Food irradiation is the treatment of food with ionizing radiation. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Irradiating food can destroy insects and bacteria by creating free radicals and radiolytic products that can break apart cell membranes. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Food irradiation has produced no observable negative short-term effects for humans, but its long-term effects are unknown. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Nuclear fusion is a reaction in which two nuclei are combined to form a larger nucleus. It releases energy when light nuclei are fused to form medium-mass nuclei. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
Fusion is the source of energy in stars, with the proton-proton cycle,1H+1Hâ2H+e++ve(0.42 MeV)1H+1Hâ2H+e++ve(0.42 MeV)1H+2Hâ3He+γ(5.49 MeV)1H+2Hâ3He+γ(5.49 MeV)3He+3Heâ4He+1H+1H(12.86 MeV)3He+3Heâ4He+1H+1H(12.86 MeV)being the principal sequence of energy-producing reactions in our Sun. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
being the principal sequence of energy-producing reactions in our Sun. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
The overall effect of the proton-proton cycle is2eâ+41Hâ4He+2ve+6γ(26.7 MeV),2eâ+41Hâ4He+2ve+6γ(26.7 MeV),where the 26.7 MeV includes the energy of the positrons emitted and annihilated. | https://openstax.org/books/college-physics-2e/pages/32-section-summary |
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