Understanding Neutron Radiography Post Exam Reading VIII-Part 2a of 2A

More documents

Recommendations

Info

Visualization of Geiger Muller Gas Magnification Event- Townsend Avalanches Visualization of the spread of Townsend avalanches by means of UV photons. This mechanism allows a single ionising event to ionise all the gas surrounding the anode by triggering multiple avalanches. Charlie Chong/ Fion Zhang
Properties Extension of the gas avalanche increases the gas amplification factors so that 10 9 to 10 10 ion pairs are formed in the discharge. This results in an output pulse large enough (0.25 to 10 V) to require no sophisticated electronic amplification circuitry for readout. At this voltage, the size of all pulses, regardless of the nature of the ionization, is the same. When operated in the geiger-müller region, a counter cannot distinguish among the several types of radiation and therefore is not useful for spectroscopy or for the detection of one energy event in the presence of another. An external shield is often used to filter out alpha and beta particles in the presence of gamma energies. Note: The amplification factor: 10 9 to 10 10 ion pairs are formed in the discharge for single ionization of multiple events avalanches Charlie Chong/ Fion Zhang
Page 1 and 2:
Understanding Neutron Radiography R
Page 3 and 4:
Spallation Source Charlie Chong/ Fi
Page 5 and 6:
Spallation Source Charlie Chong/ Fi
Page 7 and 8:
Charlie Chong/ Fion Zhang
Page 9 and 10:
3. Techniques/Calibrations • Bloc
Page 11 and 12:
Charlie Chong/ Fion Zhang Fion Zhan
Page 13 and 14:
Gamma- Radiography TABLE 1. Charact
Page 15 and 16:
Page 17 and 18:
Charlie Chong/ Fion Zhang http://gr
Page 19 and 20:
Whole Chapter 5 Radiation Measureme
Page 21 and 22:
Radiation Detection Systems Some fo
Page 23 and 24:
PART 2. Ion Chambers and Proportion
Page 25 and 26:
FIGURE 1. Ion pair (showing ejected
Page 27 and 28:
FIGURE 2. Basic ionization chamber
Page 29 and 30:
Photoelectric Absorption An atom co
Page 31 and 32:
Compton Scatter Collision of a phot
Page 33 and 34:
Pair Production Note pair productio
Page 35 and 36:
Linear Energy Transfer [LET] LET is
Page 37 and 38:
Simulation of various radiation ene
Page 39 and 40:
Sources of Attenuation The attenuat
Page 41 and 42:
Page 43 and 44:
Charlie Chong/ Fion Zhang http://ra
Page 45 and 46:
The electron that is removed is the
Page 47 and 48:
Photoelectric effect ABSORBED Charl
Page 49 and 50:
Compton effect or Compton scatter i
Page 51 and 52:
Page 53 and 54:
The reason at least 1.022 MeV of ph
Page 55 and 56:
Pair Production Charlie Chong/ Fion
Page 57 and 58:
Photoelectric (PE) absorption Photo
Page 59 and 60:
This second applet is similar to th
Page 61 and 62:
Photoelectric effect, or photoelect
Page 63 and 64:
First principle mechanism of ioniza
Page 65 and 66:
Photoelectron Spectroscopy Charlie
Page 67 and 68:
Photoelectron Spectroscopy Charlie
Page 69 and 70:
Thomson scattering (R), also known
Page 71 and 72:
Ion current chambers have a respons
Page 73 and 74:
FIGURE 4. Energy and directional re
Page 75 and 76:
Ionization Chambers Charlie Chong/
Page 77 and 78:
Compton scattering (C) (incoherent
Page 79 and 80:
Output Current Measurements The ion
Page 81 and 82:
Vibrating Reed Electrometers An alt
Page 83 and 84:
Vibrating Reed Electrometers Cary V
Page 85 and 86:
The weak current generated in the c
Page 87 and 88:
Older electrometers Gold-leaf elect
Page 89 and 90:
Charlie Chong/ Fion Zhang Volta Ele
Page 91 and 92:
Gold-leaf electroscope Charlie Chon
Page 93 and 94:
Vibrating reed electrometers Vibrat
Page 95 and 96:
FIGURE 7. Examples of ionization ch
Page 97 and 98: FIGURE 8. Cross section of quartz f
Page 99 and 100: Quartz Fiber Pocket Dosimeter. Char
Page 105 and 106: Manhattan Project Charlie Chong/ Fi
Page 109 and 110: Charlie Chong/ Fion Zhang
Page 113 and 114: WWII Charlie Chong/ Fion Zhang
Page 115 and 116: Ion Chamber Charger & Reader Radiac
Page 119 and 120: Pocket dosimeters tended to be slig
Page 121 and 122: Quartz Fiber Pocket Dosimeter. CDV-
Page 125 and 126: Ion Chamber Charger & Reader Charli
Page 127 and 128: WWII Heroes Charlie Chong/ Fion Zha
Page 129 and 130: FIGURE 8. Cross section of quartz f
Page 131 and 132: FIGURE 10. Energy dependence of res
Page 133 and 134: Proportional Counters If the electr
Page 135 and 136: Townsend Discharges (Avalanches) Th
Page 137 and 138: General description of the phenomen
Page 139 and 140: The avalanche mechanism is shown in
Page 141 and 142: Visualization of Proportional Count
Page 143 and 144: Multiple Gas Amplification due to m
Page 145 and 146: PART 3. Geiger-Müller Counters Ope
Page 147: Visualization of Geiger Muller Gas
Page 151 and 152: Correct counting rate R can be calc
Page 153 and 154: FIGURE 11. Resolving time, dead tim
Page 155 and 156: FIGURE 12. Processing of detector i
Page 157 and 158: Quenching As positive ions are coll
Page 159 and 160: FIGURE 13. Assortment of geiger-mü
Page 161 and 162: Geiger Muller Charlie Chong/ Fion Z
Page 169 and 170: Design Variations Geiger-müller co
Page 171 and 172: FIGURE 14. Dose rate ratio versus e
Page 173 and 174: TABLE 1. Characteristics of three i
Page 175 and 176: Mini Geiger Muller Alarm Meter Char
Page 177 and 178: Mini Geiger Muller Alarm Meter Char
Page 183 and 184: FIGURE 15. Typical energy response
Page 185 and 186: (b) radiation incident on side vers
Page 187 and 188: (d) radiation incident normal to lo
Page 189 and 190: TABLE 3. Common scintillators. Char
Page 191 and 192: FIGURE 16. Energy diagram of scinti
Page 193 and 194: Desirable Scintillator Characterist
Page 195 and 196: Electron multiplication, or gain, i
Page 197 and 198: PMT Charlie Chong/ Fion Zhang
Page 199 and 200:
PMT Charlie Chong/ Fion Zhang
Page 201 and 202:
System Electronics Once the output
Page 203 and 204:
PART 5. Luminescent Dosimetry Therm
Page 205 and 206:
Thermoluminescence Charlie Chong/ F
Page 207 and 208:
Disadvantages include the loss of i
Page 209 and 210:
Thermoluminescent Dosimetric Readou
Page 211 and 212:
FIGURE 20. Typical glow curve. Inte
Page 213 and 214:
TDL Charlie Chong/ Fion Zhang http:
Page 215 and 216:
TDL Charlie Chong/ Fion Zhang http:
Page 217 and 218:
PART 6. Neutron Detection Character
Page 219 and 220:
TABLE 4. Neutron classification. Cl
Page 221 and 222:
Scintillation Scintillators contain
Page 223 and 224:
TABLE 6. Properties of Some Thermal
Page 225 and 226:
Detector The diffused p-n junction
Page 227 and 228:
Surface Barrier Detectors The opera
Page 229 and 230:
TABLE 5. Radiation detector types.
Page 231 and 232:
FIGURE 21. Cross sections: (a) diff
Page 233 and 234:
PART 8. Film Badges One of the most
Page 235 and 236:
The absorption of a single photon o
Page 237 and 238:
Compounds that can be used as photo
Page 240 and 241:
Page 242 and 243:
show all

Understanding Neutron Radiography Post Exam Reading VIII-Part 2a of 2A

Create successful ePaper yourself

Delete template?

Save as template?