Table 3 Modification of the Procedure used for Fission Track Autoradiography of Marchaii’ latands Teeth Samples Step Modification Dehydcation none Infiltration none Embedding and Curing instead of Solution B from Polysciunce Inc. as accelerator, use 2,2' Azobisiso butyrontrile ALBN (0.5% by weight). The methyl methacrylate plus ALBN will be exposed to uv light,overnight-1 day. The new procedure should result in a harder polymer. To provide easy release of the specimen from the mold, a release agent such as silicon grease (20% py wt.) dissolved in methyl methacrylate can be used Co coat the inside of the glass mold. Sectioning Sections as Preparation for a) If Al thin as 250 om will] be attempted. foil were to be used, several pieces of lexan or polyethylene ¢ises snould be placed between the foil and the "teeth sandwich" Irradiation b) A new set-up without the use of Al foil is being planned Instead of the "rabbit" pneumatic tube irradiation Ivrvadiation facility, the “aluminum can' radial set-up will be used; the former has an hf ease ratio of 33 and temperature is greater than or equal to 50°C whereas the latter has a ratio _of 300 and temp. is greater than or equal to 30°C. Irradiation time has to be increased considgrably ince the Former has a neutron flux os 10 “ng/em' sec whereas the latter of 3xlL0 nt/em sec, smaller by a factor of 3. The irradiation time used previously is too short, as observed from the Pu tracks, and may have to be increased 2 &. Thus the new irradiation time may be 8-10 hrs. Etching for long irradiation i dine , grgater than or equal to JO hers at the 3x10 nt/eom sec flux, Billie Oltman of SNL aiyeests Lower temperalure and lon- ger etching time, 44°C, 90 minutes. If 60°C is to be retained, 35 minutes etching time was recommended. He also recommends partial immersion instead of total immersion- etch the side against the teeth specimen only. The set-up used at ANL is 6.25M KOH in a 1500 mL pyrex tray on top of a hot plate with temperature measured by a thermometer. This should improve signal —< an = = 2 \ make to noise ratio and also track counting Jess confusing.