4/2003 Rev 2 II.3.6 – slide 1 of 18 Part IIQuantities and Measurements Module 3Principles of Radiation Detection and Measurement Session 6Photographic Emulsions Session II.3.6 IAEA Post Graduate Educational Course Radiation Protection and Safe Use of Radiation Sources

4/2003 Rev 2 II.3.6 – slide 2 of 18 Overview  In this Session we will discuss photographic emulsions and their use as radiation dosimeters.

4/2003 Rev 2 II.3.6 – slide 3 of 18 A film badge is a passive dosimeter It can measure deep, eye and skin dose depending on the filtration used It can also indicate the energy of the radiation to which it was exposed Film Badge

4/2003 Rev 2 II.3.6 – slide 4 of 18 Common Passive Personal Dosimeters Film Badge  Cheap  Permanent record  Energy correction required Thermoluminescent Dosimeter (TLD)  Re-useable  Easily automated  More sensitive than film

4/2003 Rev 2 II.3.6 – slide 5 of 18 Typical Processed Dosimetry Film  Film holder has many different absorbers (filters)  Differential reading and appropriate calibration allows assessment of radiation quality (type and energy) and dose

4/2003 Rev 2 II.3.6 – slide 6 of 18  Film dosimeters (commonly known as film badges) consist of a piece of photographic film in a holder  The holder is fitted with a range of filters which allows us to distinguish between beta, x-ray, gamma and thermal neutron radiations and also allows determination of the personal dose equivalent for H p (10), H p (0.07) and H p (3) Film Dosimeter

4/2003 Rev 2 II.3.6 – slide 7 of 18  By determining the degree of blackening (optical density) on the developed film and comparing it with calibrated films that have been exposed to known doses, it is possible to ascertain both the total dose received by the wearer and also the contribution to total dose by each type of radiation  The various filters used in film badges to ascertain whole body H p (10), skin H p (0.07) and eye H p (3) doses are shown in the following Figure and Table Film Dosimeter

4/2003 Rev 2 II.3.6 – slide 8 of 18 Film Dosimeter

4/2003 Rev 2 II.3.6 – slide 9 of 18 Filter MaterialApplication Open Windowbeta and very soft x-rays Plastic (50 mg cm -2 )  and x-ray dose and energy* Plastic (300 mg cm -2 )  and x-ray dose and energy* Dural (0.040”)  and x-ray dose and energy* Sn + Pb (0.028” 0.012”)  and x-ray dose and energy* Cd + Pb (0.028” 0.012”)slow neutrons** Lead (0.012”)edge shielding + Indium (0.4 g)neutron accident monitoring * quantitative determination of ** by gamma emitted after capture by cadmium + to prevent overlap of film blackening due to angled incident radiation Film Dosimeter

4/2003 Rev 2 II.3.6 – slide 10 of 18  Film badges are particularly useful for measuring doses to individuals as information on both the type and energy of the radiation received can often be determined  Also, the presence of surface contamination on the holder can be ascertained by an irregular darkening of the film  Another advantage of this type of dosimeter is that the films can be kept as a permanent record of an individual’s dose Film Dosimeter

4/2003 Rev 2 II.3.6 – slide 11 of 18  This means that they can be reassessed at a later date if necessary  Undesirable features of the film badge are their adverse effects to light and heat  They also require dark room facilities (with associated development chemicals) and significant manual handling during assessment  Another major disadvantage is that the films cannot be reused and, although they are cheap, they are in limited supply Film Dosimeter

4/2003 Rev 2 II.3.6 – slide 12 of 18 Film Dosimeter

4/2003 Rev 2 II.3.6 – slide 13 of 18 Film Properties

4/2003 Rev 2 II.3.6 – slide 14 of 18 Film Properties

4/2003 Rev 2 II.3.6 – slide 15 of 18 The density on the film results from three basic sources:  Base  Fog  Exposure Film Properties

4/2003 Rev 2 II.3.6 – slide 16 of 18 DOSIMETER FILM Black = exposed White = not exposed How was this film badge exposed? Pb Filter Exposed Personnel Dosimeter Al Filter

4/2003 Rev 2 II.3.6 – slide 17 of 18 openwindow Shallow to deep ratio = H p (10) H p (0.07) 0° 45  90° Orientation Effects

4/2003 Rev 2 II.3.6 – slide 18 of 18 Where to Get More Information  Cember, H., Introduction to Health Physics, 3 rd Edition, McGraw-Hill, New York (2000)  Firestone, R.B., Baglin, C.M., Frank-Chu, S.Y., Eds., Table of Isotopes (8 th Edition, 1999 update), Wiley, New York (1999)  International Atomic Energy Agency, The Safe Use of Radiation Sources, Training Course Series No. 6, IAEA, Vienna (1995)