Radioactive decay is the process by which an

Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting ionizing particles or radiation. The emission is spontaneous in that the nucleus decnt nuclide, transforming to an atom of ays without collision with another particle. This decay, or loss of energy, results in an atom of one type, called the parea different type, named the daughter nuclide, 14 C ------- 15 N

RADIOACTIVE DECAY • Atom (nuclei) yang mempunyai rasio proton – neutron berada di luar Belt of stability secara langsung akan mengalami radioactive decay secara Spontan • Tipe Decay tergantung dimana posisi atom berada relative terhadap band of stability • Radioactive particle are emitted with different kinetic energy - Energy change is related to the change in binding energy from reactant to product

BAND STABILITY AND RADIOACTIVE DECAY

Mode of decay Participating particles Daughter nucleus Decays with emission of nucleons: Alpha decay Proton emission Neutron emission Double proton emission Spontaneous fission Cluster decay An alpha particle (A = 4, Z = 2) emitted from nucleus A proton ejected from nucleus A neutron ejected from nucleus Two protons ejected from nucleus simultaneously Nucleus disintegrates into two or more smaller nuclei and other particles Nucleus emits a specific type of smaller nucleus (A 1, Z 1) smaller than, or larger than, an alpha particle (A − 4, Z − 2) (A − 1, Z − 1) (A − 1, Z) (A − 2, Z − 2) — (A − A 1, Z − Z 1) + (A 1, Z 1) Different modes of beta decay: A nucleus emits an electron and an (A, Z + 1) electron antineutrino A nucleus emits a positron and a electron Positron emission (β+ decay) (A, Z − 1) neutrino A nucleus captures an orbiting electron and emits a neutrino – the daughter Electron capture (A, Z − 1) nucleus is left in an excited and unstable state A nucleus emits two electrons and two Double beta decay (A, Z + 2) antineutrinos A nucleus absorbs two orbital electrons and emits two neutrinos – the daughter Double electron capture (A, Z − 2) nucleus is left in an excited and unstable state A nucleus absorbs one orbital electron, Electron capture with positron emission (A, Z − 2) emits one positron and two neutrinos A nucleus emits two positrons and two Double positron emission (A, Z − 2) neutrinos Transitions between states of the same nucleus: Excited nucleus releases a high-energy Isomeric transition (A, Z) photon (gamma ray) Excited nucleus transfers energy to an Internal conversion orbital electron and it is ejected from the (A atom β− decay

CONTOH NATURAL DECAY An example is the natural decay chain of 238 U which is as follows: decays, through alpha-emission, with a half-life of 4. 5 billion years to thorium-234 which decays, through beta-emission, with a half-life of 24 days to protactinium-234 which decays, through beta-emission, with a half-life of 1. 2 minutes to uranium-234 which decays, through alpha-emission, with a half-life of 240 thousand years to thorium -230 which decays, through alpha-emission, with a half-life of 77 thousand years to radium 226 which decays, through alpha-emission, with a half-life of 1. 6 thousand years to radon 222 which decays, through alpha-emission, with a half-life of 3. 8 days to polonium-218 which decays, through alpha-emission, with a half-life of 3. 1 minutes to lead-214 which decays, through beta-emission, with a half-life of 27 minutes to bismuth-214 which decays, through beta-emission, with a half-life of 20 minutes to polonium-214 which decays, through alpha-emission, with a half-life of 160 microseconds to lead-210 which decays, through beta-emission, with a half-life of 22 years to bismuth-210 which decays, through beta-emission, with a half-life of 5 days to polonium-210 which decays, through alpha-emission, with a half-life of 140 days to lead-206, which is a stable nuclide.

Nuclear Stability and Radioactive Decay Beta decay 14 C 6 40 K 19 14 N + 0 b + n Decrease # of neutrons by 1 7 -1 40 Ca + 0 b + n Increase # of protons by 1 -1 20 1 n 0 1 p + 0 b + n 1 -1 Positron decay 11 C 11 B + 0 b + n +1 Increase # of neutrons by 1 38 K 38 Ar + 0 b + n Decrease # of protons by 1 6 19 5 18 +1 1 p 1 n and 1 n + 0 b + n 0 +1 n have A = 0 and Z = 0

Nuclear Stability and Radioactive Decay Electron capture decay 37 Ar + 0 e 55 Fe + 18 26 37 Cl -1 0 e + n 55 Mn 25 -1 Increase # of neutrons by 1 17 + n Decrease # of protons by 1 1 Alpha decay 1 p + 0 e -1 1 n +n 0 Decrease # of neutrons by 2 212 Po 84 4 He 2 + 208 Pb 82 Decrease # of protons by 2 Spontaneous fission 252 Cf 98 HITUNG PERUBAHAN ENERGI BINDING PADA PROSES DECAY DIATAS ? 2125 In + 21 n 49 0 23. 2

HALF-LIFE • • HALF-LIFE is the time that it takes for 1/2 a sample to decompose. The rate of a nuclear transformation depends only on the “reactant” concentration.

HALF-LIFE Decay of 20. 0 mg of 15 O. What remains after 3 half-lives? After 5 half-lives?

263 Sg ----> 259 Rf + 4 He

Terjadi pada Solar Energi dan Proses terjadinya alam semesta Terjadi pada proses bom nuklir dan reaktor nuklir kini

KINETICS OF RADIOACTIVE DECAY For each duration (half-life), one half of the substance decomposes. For example: Ra-234 has a half-life of 3. 6 days If you start with 50 grams of Ra-234 After 3. 6 days > 25 grams After 7. 2 days > 12. 5 grams After 10. 8 days > 6. 25 grams

The probability of decay (−d. N/N) is proportional to dt: The solution to this first-order differential equation is the following function: Dimana, The half life is related to the decay constant as follows:

Kinetics of Radioactive Decay N daughter DN rate = - rate = l. N Dt - DN Dt = l. N ln. N = ln. N 0 - lt N = N 0 e(-lt) N = the number of atoms at time t N 0 = the number of atoms at time t = 0 l is the decay constant (sometimes called k) l = Ln 2 t½ k= 23. 3

ACTIVITY CALCULATION N = N 0 e(-lt) UNTUK HALF LIFE 2, 303 Log 0, 5/1 = -λ t½ λ = 0, 693/t½ A = A 0 e(-l t ) ECERCISE : Hitung sisa aktifitas Tritium setela tersimpan 26 tahun dari aktifitas semula 15 Ci, t 1/2 tritium = 12, 34 th

A sample of C 14, whose half life is 5730 years, has a decay rate of 14 disintegration per minute (dpm) per gram of natural C. An artifact is found to have radioactivity of 4 dpm per gram of its present C, how old is the artifact? Using the above equation, we have: Where: years

Kinetics of Radioactive Decay ln[N] = ln[N]0 - lt ln [N] [N] = [N]0 exp(-lt) 23. 3

QUANTITATIVE ASPECT OF RADIACTIVE DECAY 238 U Arithmetically, melalui term half life kemudian dapat dihitung perubahan jumlah/aktivitas zat radioaktive selama waktu tertentu • Graphycally, Mengunakan grafik semilog antara Aktivita radioaktiv Vs waktu • Radioactive Equilibrium - Ratio Nomor atom pada proses reaksi decay zat radioaktive seperti dibawah ini, 238 U λu 234 Th λTh 234 Pa NTh / NU = λ U / λ Th N Th / N U = t½ Th / t½ U • - Hal yang sama untuk atome decay dengan nomor atom yang kostan , Ratio Massa ebanding dengan ratio half life nya, Massa X / Massa Y = t½ X . A X / t½ Y . A Y Dari perhitungan ratio nomor atom dan massa ada decay reaction maka dapat dihitung ratio dari ratio nomor atom dan mass dari hasil decay tersebut

Nuclear Reaction

Balancing Nuclear Equations 1. Conserve mass number (A). The sum of protons plus neutrons in the products must equal the sum of protons plus neutrons in the reactants. 235 U + 1 n 92 0 138 Cs 55 + 96 Rb 37 +2 1 n 0 235 + 1 = 138 + 96 + 2 x 1 2. Conserve atomic number (Z) or nuclear charge. The sum of nuclear charges in the products must equal the sum of nuclear charges in the reactants. 235 U + 1 n 92 0 138 Cs 55 92 + 0 = 55 + 37 + 2 x 0 + 96 Rb 37 +2 1 n 0 23. 1

NUCLEAR REACTIONS • Alpha emission Note that mass number (A) goes down by 4 and atomic number (Z) goes down by 2. Nucleons (nuclear particles… protons and neutrons) are rearranged but conserved

NUCLEAR REACTIONS • Beta emission Note that mass number (A) is unchanged and atomic number (Z) goes up by 1.

OTHER TYPES OF NUCLEAR REACTIONS Positron (0+1 b): a positive electron 207 Electron capture: the capture of an electron Electron capture: 207

ARTIFICIAL NUCLEAR REACTIONS New elements or new isotopes of known elements are produced by bombarding an atom with a subatomic particle such as a proton or neutron -- or even a much heavier particle such as 4 He and 11 B. Reactions using neutrons are called g reactions because a g ray is usually emitted. Radioisotopes used in medicine are often made by g reactions.

NUCLEAR BOMBARDMENT REACTIONS Cyclotron or accelerator Nuclear reactor

ARTIFICIAL TRANSMUTATION TROUGH ACCELERATOR

CROSS SECTION Is the probability that a bombarding particle (neutron) will produce a nuclear reaction Cross section Unit is Barn (1 barn = 1024 cm-2) Formula ; N = Φ x σ x n. X Where, N = Total number of reaction Φ = Flux neutron σ = nuclear cross section

NUCLEAR CROSS SECTION

ARTIFICIAL NUCLEAR REACTIONS Example of a g reaction is production of radioactive 31 P for use in studies of P uptake in the body. 31 P + 1 n ---> 32 P + g 15 0 15

TRANSURANIUM ELEMENTS Elements beyond 92 (transuranium) made starting with an g reaction 238 U + 1 n ---> 239 U + g 92 0 92 239 U 92 ---> 23993 Np + 0 -1 b 23993 Np ---> 23994 Pu + 0 -1 b

NUCLEAR FISSION

NUCLEAR FISSION Fission is the splitting of atoms These are usually very large, so that they are not as stable Fission chain has three general steps: 1. Initiation. Reaction of a single atom starts the chain (e. g. , 235 U + neutron) 2. Propagation. 236 U fission releases neutrons that initiate other fissions 3. ______EXCERCISE , REACTION FISSION RANTAI URANIUM.

Nuclear Fission 235 U + 1 n 90 Sr + 143 Xe + 31 n + Energy 92 0 38 54 0 Energy = [mass 235 U + mass n – (mass 90 Sr + mass 143 Xe + 3 x mass n )] x c 2 Energy = 3. 3 x 10 -11 J per 235 U = 2. 0 x 1013 J per mole 235 U Combustion of 1 ton of coal = 5 x 107 J 23. 5

REPRESENTATION OF A FISSION PROCESS.

Nuclear Fission Nuclear chain reaction is a self-sustaining sequence of nuclear fission reactions. The minimum mass of fissionable material required to generate a self-sustaining nuclear chain reaction is the critical mass. Non-critical Critical 23. 5

DIAGRAM OF A NUCLEAR POWER PLANT

a neutron moderator is a medium that reduces the speed of fast neutrons, thereby turning them into thermal neutrons capable of sustaining a nuclear chain reaction involving uranium-235.

A control rod is a rod made of chemical elements capable of absorbing many neutrons without fissioning themselves. They are used in nuclear reactors to control the rate of fission of uranium and plutonium. Because these elements have different capture cross sections for neutrons of varying energies, the compositions of the control rods must be designed for the neutron spectrum of the reactor it is supposed to control. Light water reactors (BWR, PWR) and heavy water reactors (HWR) operate with "thermal" neutrons, whereas breeder reactors operate with "fast" neutrons. A coolant is a fluid which flows through a device to prevent its overheating, transferring the heat produced by the device to other devices that use or dissipate it. An ideal coolant has high thermal capacity, low viscosity, is low-cost, non-toxic, and chemically inert, neither causing nor promoting corrosion of the cooling system. Some applications also require the coolant to be an electrical insulator. Silver-indium-cadmium alloys, generally 80% Ag, 15% In, and 5% Cd, are a common control rod material for pressurized water reactors. The somewhat different energy absorption regions of the materials make the alloy an excellent neutron absorber. It has good mechanical strength and can be easily fabricated. It has to be encased in stainless steel to prevent corrosion in hot water.

NUCLEAR FISSION & POWER Currently about 103 nuclear power plants in the U. S. and about 435 worldwide. 17% of the world’s energy comes from nuclear.

NUCLEAR FUSION Fusion small nuclei combine 2 H + 3 H 4 He + 1 n + 1 2 0 Occurs in the sun and other stars Energy

Nuclear Fusion Reaction 1 Energy Released 2 H + 2 H 3 H + 1 H 1 1 1 2 H + 3 H 4 He + 1 n 1 1 2 6 Li + 2 H 2 4 He 3 1 0 6. 3 x 10 -13 J 2. 8 x 10 -12 J 3. 6 x 10 -12 J 2 Tokamak magnetic plasma confinement 23. 6

NUCLEAR FUSION Fusion Excessive heat can not be contained Attempts at “cold” fusion have FAILED. “Hot” fusion is difficult to contain

RADIATION CHEMISTRY Mempelajari efek kimia yang di timbulkan oleh radiasi pengion bila ia diserap oleh materi RADIASI : Emisi dan propagasi energi dalam udara dan suatu materi RADIASI PENGION : Dapat mengionkan dan mengeksitasi target (Partikel bermuatan/ion /elektron, Gel elektromagnetik/gamma and sinar x, neutron) IONISASI : Pelepasan elektron dari orbital suatu atom/molekul netral - elektron yang terikan paling lemah - terbentuk ion positif dan elektron bebas - hanya bisa ditimbulkan oleh radiasi pengion EKSITASI : Perpindahan elektron ke orbital lebih tinggi dalam suatu atom/molekul netral menjadi atom/molekul mempunyai energi berlebih - kembali ke tingkat semula dengan disertai emisi cahaya atau - terjadi pemutusan ikatan yang lemah menghasilkan radikal bebas IRADIASI : Paparan terhadap radiasi pengion (berdaya tembus)

Spektrum elektromagnetik Radiasi pengion Radiasi non-pengion Matahari/p Pemancar /lampu emanas UV Matahari/bola Tabung pijar Pemancar/microwave oven sinar X Matahari/ radio isotop

SUMBER RADIASI RADIOISOTOPE ALAM DAN BUATAN----- FOTON DAN PARTIKEL MESIN PEMERCEPAT (ACCELERATOR) PATIKEL----- BERKAS ELEKTRON, BERKAS ION REAKTOR NUKLIR ----- BERKAS NETRON KARAKTERISASI RADIASI PENGION : DAYA TEMBUS DAN LET Radiation pengion mempunyai daya tembus, tergantung pada jenis radiasi, energi foton/partikel dan kerapatan target LET = Linier Energy Transer defined as the linier (distance) rate at which energy is lost by radiation traversing a material medium in unit kev/µ

Radiasi Sinar Gamma terhadap Materi DNA Sel Mikroba Patogen terkena radiasi menjadi tidak mampu berreplikasi dan mati

Daya tembus Sinar gamma > sinar x > partikel beta > partikel alpha Partikel alpha > partikel beta > sinar x > sinar gamma L E T

Linear energy transfer (LET) is a measure of the energy transferred to material as an ionizing particle travels through it. Typically, this measure is used to quantify the effects of ionizing radiation on biological specimens or electronic devices. Linear energy transfer is closely related to stopping power. Whereas stopping power, the energy loss per unit distance, d. E / dx

PROPERTIES OF NUCLEAR RADIATIONS ENERGY RANGE TYPE OF RADIATIONS LET VALUE IN WATER (kev/µ) 4 Me. V – 9 Me. V Alpha 5 Me. V 140 0, 5 Me. V – 2 Me. V Beta 2 Me. V 0, 2 0, 1 Me. V - 2 Me. V Gamma 1, 25 Me. V 0, 3 - X- Rays 200 Ke. V 3

INTERACTION PARTICLE WITH MATTER PARTIKEL ALPHA - Daya tembus di udara antara 2, 5 – 9 cm sedangkan untuk aluminium antara 0, 02 mm – 0, 006 mm - Electrostatic interaction dgn orbital electron menghasilkan ionisasi dan ion pair (ion positive dan ejected electron) PARTIKEL BETA - Daya tembus 500 kali partikel alpha pada energi yang sama - Production of ion pair - Interaction of fast moving of beta particle produced electromagnetic radiation (X-ray and gamma ray) near positive field of nucleus disertai efect bremsstrahlung (slowing down radiation)

Partikel pengion IONISASI EKSITASI e- ionisasi α e- elektron ee- e- Partikel pengeksitasi e- REAKSI INTI 4 Be 9 + 2 He 4 ------ 6 C 13 + 1 H 1

INTERAKSI PARTIKEL BETA -Ionisasi -Eksitasi -Bremstrahlung e- ß Sinar x eee- e- e. Elektron dg energi Berkurang /Bremsstraslung

Gamma Rays -Photoelectric absorption, gamma photon expends all of its energy to eject an orbital electron from inner shell (beta particle), energi foton < 1 Me. V seluruhnya diserap oleh target -Comfton effect, only part of the original gamma energy is used to eject a bound electron, and partly as gamma scattered (energy gamma about 1 - 5 Me. V) -Pair Production, interaksi menghasilkan pasangan elektron-positron (energy gamma about 5 Me. V), konversi foton oleh medan magnet inti menjadi elektron dan positron--- akan mengionisasi. Elektron dan

TUNGSTEN TARGET ATOM Z = 74 K-shell: 69. 5 ke. V L-shell: 12 ke. V M-shell: 3 ke. V N-shell: 1 ke. V O-shell: 0. 1 ke. V Denise Moore, Sinclair Community College

BREMSSTRAHLUNG RADIATION PRODUCTION The projectile electron interacts with the nuclear force field of the target tungsten atom The electron (-) is attracted to the nucleus (+) The electron DOES NOT interact with the orbital shell electrons of the atom Always produced = 100% of time http: //www. internaldosimetry. com/courses/ introdosimetry/images/Particles. Brem. JPG

BREMSSTRAHLUNG RADIATION PRODUCTION As the electron gets close to the nucleus, it slows down (brems = braking) and changes direction The loss of kinetic energy (from slowing down) appears in the form of an x-ray The closer the electron gets to the nucleus the more it slows down, changes direction, and the greater the energy of the resultant x-ray The energy of the x-ray can be anywhere from almost 0 (zero) to the level of the k. Vp

X- AND GAMMA-RAY INTERACTIONS Rayleigh scattering Compton scattering Photoelectric absorption Pair production

RAYLEIGH SCATTERING Incident photon interacts with and excites the total atom as opposed to individual electrons Occurs mainly with very low energy diagnostic x-rays, as used in mammography (15 to 30 ke. V) Less than 5% of interactions in soft tissue above 70 ke. V; at most only 12% at ~30 ke. V

RAYLEIGH SCATTERING

COMPTON SCATTERING Predominant interaction in the diagnostic energy range with soft tissue Most likely to occur between photons and outer (“valence”) shell electrons Electron ejected from the atom; photon scattered with reduction in energy Binding energy comparatively small and can be ignored

Dowd, S. B. Practical Radiation Protection and Applied Radiobiology

COMPTON SCATTERING

COMPTON SCATTER PROBABILITIES As incident photon energy increases, scattered photons and electrons are scattered more toward the forward direction These photons are much more likely to be detected by the image receptor, reducing image contrast Probability of interaction increases as incident photon energy increases; probability also depends on electron density Number of electrons/gram fairly constant in tissue; probability of Compton scatter/unit mass independent of Z

RELATIVE COMPTON SCATTER PROBABILITIES

COMPTON SCATTERING Laws of conservation of energy and momentum place limits on both scattering angle and energy transfer Maximal energy transfer to the Compton electron occurs with a 180 -degree photon backscatter Scattering angle for ejected electron cannot exceed 90 degrees Energy of the scattered electron is usually absorbed near the scattering site

COMPTON SCATTERING Incident photon energy must be substantially greater than the electron’s binding energy before a Compton interaction is likely to take place Probability of a Compton interaction increases with increasing incident photon energy Probability also depends on electron density (number of electrons/g density) With exception of hydrogen, total number of electrons/g fairly constant in tissue Probability of Compton scatter per unit mass nearly independent of Z

PHOTOELECTRIC ABSORPTION All of the incident photon energy is transferred to an electron, which is ejected from the atom Kinetic energy of ejected photoelectron (Ec) is equal to incident photon energy (E 0) minus the binding energy of the orbital electron (Eb) Ec = Eo - Eb

Dowd, S. B. Practical Radiation Protection and Applied Radiobiology

PHOTOELECTRIC ABSORPTION (I-131)

PHOTOELECTRIC ABSORPTION Incident photon energy must be greater than or equal to the binding energy of the ejected photon Atom is ionized, with an inner shell vacancy Electron cascade from outer to inner shells Characteristic x-rays or Auger electrons Probability of characteristic x-ray emission decreases as Z decreases Does not occur frequently for diagnostic energy photon interactions in soft tissue

PHOTOELECTRIC ABSORPTION (I-131)

PHOTOELECTRIC ABSORPTION Probability of photoelectric absorption per unit mass is approximately proportional to No additional nonprimary photons to degrade the image Energy dependence explains, in part, why image contrast decreases with higher x-ray energies

PHOTOELECTRIC ABSORPTION Although probability of photoelectric effect decreases with increasing photon energy, there is an exception Graph of probability of photoelectric effect, as a function of photon energy, exhibits sharp discontinuities called absorption edges Photon energy corresponding to an absorption edge is the binding energy of electrons in a particular shell or subshell

PHOTOELECTRIC MASS ATTENUATION COEFFICIENTS

PHOTOELECTRIC ABSORPTION At photon energies below 50 ke. V, photoelectric effect plays an important role in imaging soft tissue Process can be used to amplify differences in attenuation between tissues with slightly different atomic numbers, improving image contrast Photoelectric process predominates when lower energy photons interact with high Z materials (screen phosphors, radiographic constrast agents, bone)

PERCENTAGE OF COMPTON AND PHOTOELECTRIC CONTRIBUTIONS

PAIR PRODUCTION Can only occur when the energy of the photon exceeds 1. 02 Me. V Photon interacts with electric field of the nucleus; energy transformed into an electronpositron pair Of no consequence in diagnostic x-ray imaging because of high energies required

PAIR PRODUCTION

ABSORPTION OF GAMMA RADIATION Attenuation of gamma –rays in a material is exponential, I = Io e-µx Io adalah Intensitas awal I adalah intensitas gamma setelah melalui material µ adalah koefisien absorption X adalah ketebalan material X 1/2 = 0. 693/µ

UNITS Counts per minute Curie (unit) , Bq Gray (unit) Rad (unit) Rem (unit) röntgen (unit) Sverdrup (unit) (a unit of volume transport with the same symbol Sv as Sievert) Background radiation Relative Biological Effectiveness Radiation poisoning Linear Energy Transfer

CPM AND DPM Counts per minute (cpm) is a measure of radioactivity. It is the number of atoms in a given quantity of radioactive material that are detected to have decayed in one minute. Disintegrations per minute (dpm) is also a measure of radioactivity. It is the number of atoms in a given quantity of radioactive material that decay in one minute. Dpm is similar to cpm, however the efficiency of the radiation detector CPM ~ DPM = Ef Det x CPM

UNIT RADIOACTIVITY AND DOSE One Bq is activity of a quantity of radioactive material in which one nucleus decay per second SI unit untuk Radioactivity is, Bacquerel = Bq adalah unit terkecil 1 Bq = 1 radioactive decay per second (S-1)= dis/s 1 Bq = 60 dpm Satuan Lama adalah Curie = Ci , 1 Ci = 3. 7 x 1010 Bq = 37 GBq Bq dapat dalam bentuk sbb - k. Bq , MBq, GBq, TBq and PBq Hitung : 0, 25 Ci = ……dpm ?

Pada pengukuran zat radioaktive dgn alat ukur akan terukur unit cps (count per second) or cpm (count per minute) dalam bentuk digital. Konversi cps ke absolute activity (Bq) adalah : Bq = cps x detektor effesiensi Unit of absorbed radiation dose (SI) due to ionization radiation (X-ray) is called Gray (Gy)

Absorbed dose (also known as total ionizing dose, TID) is a measure of the energy deposited in a medium by ionizing radiation. It is equal to the energy deposited per unit mass of medium, and so has the unit J/kg, which is given the special name Gray (Gy). 1 Gy of alpha radiation would be much more biologically damaging than 1 Gy of photon radiation

ABSORBED DOSE Absorbed dose ; SI , Gray (Gy, k. Gy, etc) Definition : One gray is the absorption of one joule of energy, in the form of ionizing radiation, by one kilogram of matter 1 Gy = 1 J/kg Absorbed dose = Gray (Gy), mengukur

ABSORBED DOSE Absorbed dose is the amount of energy absorbed into matter. The working SI unit is a gray (Gy), while the traditional unit is rad (rad) 1 rad = 62. 4 x 106 Me. V per gram 1 gray = 100 erg per gram 1 rad = 0. 01 gray (Gy) = 100 rad In the United States, radiation absorbed dose, dose equivalent, and exposure are often measured and stated in the older units

Rongent as radiation exposure equal to the ionization radiation will produce one esu of electricity in one cc of dry air at o. C and standard atmosfer 1 Gy ≈ 115 R The röntgen was occasionally used to measure exposure to radiation in other forms than X-rays or gamma rays 1 R = 2. 58× 10− 4 C/kg (from 1 esu ≈ 3. 33564 × 10− 10 C and the standard atmosphere air density of ~1. 293 kg/m³)

The rad (radiation absorbed dose) is a unit of absorbed radiation dose A dose of 1 rad means the absorption of 100 ergs of radiation energy per gram of absorbing material 1 Gy = 100 rad 1 roentgen (R) = 258 microcoulomb/kg (µC/kg)

When ionising radiation is used to treat cancer, the doctor will usually prescribe the radiotherapy treatment in Gy. When risk from ionising radiation is being discussed, a related unit, the sievert is used.

EQUIVALENT DOSE The equivalent dose (HT) is a measure of the radiation dose to tissue where an attempt has been made to allow for the different relative biological effects of different types of ionizing radiation Equivalent dose adalah absorbed dose + biology effect = Rongent Equivalent Man (REM) Equivalent dose (HTR) = Absorbed dose (Gy) x radiation weighting factor (Wr) Equivalent dose (SI) ---- Sievert (Sv) unit Sievert (sv) (biasanya untuk X-ray) 100 REM = 1 Sv = 1 J/kg = Gy

DOSE EQUIVALENT Dose equivalent is the absorbed dose into biological matter taking into account the interaction of the type of radiation and its associated linear energy transfer through specific tissues. The working SI unit is the sievert (Sv), while the traditional unit is roentgen equivalent man (rem). 1 Sv = 1 rads x quality factor x any other modifying factors 1 rem = 1 gray x quality factor x any other modifying factors 1 Sv =100 roentgen equivalent man (rem) 1 rem = 0. 01 Sv = 10 m. Sv

The dose equivalent is a measure of biological effect for whole body irradiation. The dose equivalent is equal to the product of the absorbed dose and the Quality Factor The millisievert is commonly used to measure the effective dose in diagnostic medical procedures (e. g. , X-rays, nuclear medicine, positron emission tomography, and computed tomography). The natural background effective dose rate varies considerably from place to place, but typically is around 2. 4 m. Sv/year that quantity of X rays which when absorbed

This variation in effect is attributed to the Linear Energy Transfer [LET] of the type of radiation, creating a different relative biological effectiveness for each type of radiation under consideration the RBE [Q] for electron and photon radiation is 1, for neutron radiation it is 10, and for alpha radiation it is 20 unit of the equivalent dose is the rem (Röntgen equivalent man); 1 Sv is equal to 100 rem, for a quality factor Q=1

Q VALUES Here are some quality factor values: [ Photons, all energies : Q = 1 Electrons all energies : Q = 1 Neutrons, energy < 10 ke. V : Q = 5 10 ke. V < energy < 100 ke. V : Q = 10 100 ke. V < energy < 2 Me. V : Q = 20 2 Me. V < energy < 20 Me. V : Q = 10 energy > 20 Me. V : Q = 5 Protons, energy > 2 Me. V : Q = 5 Alpha particles and other atomic nuclei : Q = 20

OTHER USEFUL CONVERSIONS Dose rate criteria (outside storage area): 2. 5 Sv/hr = 0. 25 mrem/hr CNSC Dose Limits (non-Nuclear Energy Worker): Whole body = 1 m. Sv/yr = 100 mrem/yr Skin, Hands, Feet = 50 m. Sv/yr = 5 rem/yr

N VALUES Here are some N values for organs and tissues: [2] Gonads: N = 0. 20 Bone marrow, colon, lung, stomach: N = 0. 12 Bladder, brain, breast, kidney, liver, muscles, oesophagus, pancreas, small intestine, spleen, thyroid, uterus: N = 0. 05 Bone surface, skin: N = 0. 01

And for other organisms, relative to humans: Viruses, bacteria, protozoans: N ≈ 0. 03 – 0. 0003 Insects: N ≈ 0. 1 – 0. 002 Molluscs: N ≈ 0. 06 – 0. 006 Plants: N ≈ 2 – 0. 02 Fish: N ≈ 0. 75 – 0. 03 Amphibians: N ≈ 0. 4 – 0. 14 Reptiles: N ≈ 1 – 0. 075 Birds: N ≈ 0. 6 – 0. 15 Humans: N = 1

EFFECTIVE DOSE Radiation source Comments m. Sv/yr mrem/yr Natural sources indoor radon due to seepage of 2. 0 222 Rn from ground radionuclides primarily 40 K and 238 U progeny in body 200 0. 39 39 terrestrial radiation due to gamma-ray 0. 28 emitters in ground 28 cosmic rays roughly doubles for 2000 m gain in elevation 0. 27 27 cosmogenic especially 14 C 0. 01 1 3. 0 300 total (rounded)

Medical sources Diagnostic xrays excludes dental examinations 0. 39 39 Medical treatments radionuclides used in diagnosis (only) 0. 14 14 total 0. 53 53 Other consumer products primarily drinking water, building materials 0. 1 10 occupational averaged over entire US population 0. 01 1 nuclear fuel cycle does not include potential reactor accidents 0. 0005 0. 05 3. 6 360 TOTAL (rounded)

JUDUL MAKALAH Proses Big bang dan pembentukan alam Radioaktive decay untuk dating (penanggalan) umur batuan (C-14 dan K/Ar) Irradiasi gamma untuk sterilisasi produk kesehatan dan makanan Reaktor nuklir untuk PLTN Teknik radiotracer untuk Industri Teknik radiasi untuk pertanian

Proses pemisahan (enrichment) bahan bakar U 235 dan U 238

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