What dosimeter should I use for personnel monitoring?
What dosimeter should I use for personnel monitoring?
Table comparing some common dosimeters used for personnel dose assessment.
| Attribute |
Film |
TLD |
OSL |
EPD |
| Radiation detected | x, γ, ß, n | x, γ, ß, n | x, γ, ß | x, γ, ß |
| Sensitive medium | Crystalline AgBr in gelatinous matrix on plastic substrate. Grain size and density vary for neutron track film vs. ß-γ film. | Crystalline thermoluminescent material, e.g., LIF (Mg, Ti), LiF(Mg, Cu, P), CaSO4 (Dy or Tm), Li2B4O7 (Cu) | Crystalline optiluminescent material, e.g., Al2O3(C) | Usually silicon diode, some use small G-M tube. |
| Dose range | 100 µSv - 5 Sv | 100 µSv - 10 Sv
(10 µSv possible) | 10 µSv - 10 Sv | 1 µSv - 10 Sv |
Energy range
(x and gamma) | 5 keV - 3 MeV | 5 keV - 6 MeV | 5 keV - 10 MeV | 50 keV - 6 MeV |
| Advantages | Relatively inexpensive; long-term visual record; provides visual image of exposure pattern. | Rugged; environmentally stable; good range; relatively rapid processing (in-house); allows infrequent readout (three months and up to one year for some); can be reused multiple times; Li phosphors have good tissue equivalence. | High sensitivity, multiple rereads possible; rapid readout; some dose imaging possible; rugged; environmentally stable; allows infrequent processing (up to one year); can be reused multiple times. | Very high sensitivity; real-time response; can display rate and integral dose; preset alarm; can provide time history of dose; can offer remote readout and computer manipulation. |
| Disadvantages | Subject to environmental influences (temp. and humidity); requires frequent processing; processing usually requires outside vendor and is relatively slow; requires filtration to account for energy dependence; fast neutrons below about 700 keV are not measured; insensitive to beta radiation below a few hundred keV. | Cannot be reread; requires capital expenditure (for in-house processing); the Ca phosphors require filtration to account for energy dependence; neutron sensitivity of albedo dosimeters decreases sharply with increasing energy. | Requires large capital expenditure (for in-house processing); vendor-supplied dosimetry likely more expensive than other vendor-supplied dosimetry. | May be subject to EM interference; may require considerable capital expenditure. |
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