Crystal Nal

To present a quantitative example of the energy conversions involved in scintillation detection, we trace the results of the interaction of a single 1.17-MeV 7 ray from 60Co with a thallium-activated sodium iodide crystal [Nal(TI)] ... 

Figure 10.10. A typical scintillation detector. (Well crystal Nal)...

The most commonly used commercial scintillation detector has a thallium-doped sodium iodide crystal, Nal(Tl), as the scintillating material. A single crystal of Nal containing a small amount of T1 in the crystal lattice is coupled to a PMT, shown in Fig. 8.25. When an X-ray photon enters the crystal, it causes the interaction... 

LiF (crystal) LiF (layer) NaBr (crystal) NaBr (layer) NaCl (crystal) NaCl (layer) NaF (crystal) NaF (layer) Nal (crystal) Nal (layer) RbCl (layer) Oxides... 

Iodide ion (I ) Alkyl chlorides and bromides are converted to alkyl iodides by treatment with sodium iodide in acetone Nal is soluble in acetone but NaCI and NaBr are insoluble and crystallize from the reaction mixture making the reac tion irreversible... 

Sodium iodide [7681-82-5] Nal, mol wt 149.92, mp 662°C, 84.66% I, forms colorless cubic crystals, which are soluble in water, ethanol, methanol, and acetone. It is used in photography, for the production of organic chemicals, and as an expectorant in cough medicines. Nal is separated by addition of sodium hydroxide or sodium carbonate to an acidic iodide solution (see also Expectorants, antitussives, and related agents). 

Sodium iodide [7681-82-5] Nal, occurs as colorless crystals or as a white crystalline solid. It has a salty and slightly bitter taste. In moist air, it gradually absorbs as much as 5% water, which causes caking or even Hquefaction (dehquescence). The soHd slowly becomes brown when exposed to air because some iodide is oxidized to iodine. Water solutions are neutral or slightly alkaline and gradually become brown for the same reason. Aqueous solutions are stabilized with respect to oxidation by raisiag the pH to 8—9.5 (see Iodine and iodine compounds). 

Sodium iodide [7681-82-5] M 149.9, m 660 , b 1304 , d 3.67. Crystd from water/ethanol soln and dried for 12h under vacuum, at 70 . Alternatively, dissolved in acetone, filtered and cooled to -20°, the resulting yellow crystals being filtered off and heated in a vacuum oven at 70 for 6h to remove acetone. The Nal was then crystd from very dilute NaOH, dried under vacuum, and stored in a vacuum desiccator [Verdin Trans Faraday Soc 57 484 1961]. 

NC samples were irradiated for 3 min and TNT and HMX for 1 min at a 14 MeV neutron flux of approx 108n/cmasec, Simultaneous counting was performed by means of a matched dual 7.6x7.6cm flat Nal crystal detector assembly in conjunction with a Kaman Nuclear programmed timer system for automatic sample transfer, A one-min count time was usually sufficient to exceed 10 counts. The signal from each de-... 

The lr Mossbauer experiments are usually carried out in transmission geometry with both source and absorber kept at liquid helium temperature and a Ge(Li) diode or a 3 mm Nal(Tl) crystal used to detect the 73 keV y-rays. The absorbers typically contain 50-500 mg cm of natural iridium, which contains 62.7% of the Mossbauer isotope lr. The isomer shifts are generally given with respect to iridium metal (the isomer shift between Os/Os and Ir metal is (0.540 0.004) mm s at 4.2 K ([268]). 

Whole organs and tissues Animal placed, backbone down in lucite box and positioned 33 cm from Nal(TI) crystal. Livers and other tissues were counted between two Nal(TI) crystals. Gamma-ray spectrometry No data No data Lloyd et al. 1970... 

Robertson [ 57 ] has measured the adsorption of zinc, caesium, strontium, antimony, indium, iron, silver, copper, cobalt, rubidium, scandium, and uranium onto glass and polyethylene containers. Radioactive forms of these elements were added to samples of seawater, the samples were adjusted to the original pH of 8.0, and aliquots were poured into polyethylene bottles, Pyrex-glass bottles and polyethylene bottles contained 1 ml concentrated hydrochloric acid to bring the pH to about 1.5. Adsorption on the containers was observed for storage periods of up to 75 d with the use of a Nal(Tl) well crystal. Negligible adsorption on all containers was registered for zinc, caesium, strontium, and... 

We expect forces in ionic compounds to increase as sizes of ions become smaller and as ionic charges become greater. As the forces between ions become stronger, a higher temperature is required to melt the crystal. In the series of compounds NaF, NaCl, NaBr, and Nal, the anions are progressively larger, and thus the ionic forces become weaker. We... 

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