JOURNAL OF CHEMICAL EDUCATION
ARTIFICIAL RADIOACTIVITY PRODUCED IN A HIGH-SCHOOL LABORATORY ROBERT A. GOUNDRY Kenmore Senior High School, Kenmore, New York and the emanations could be detected with a Geiger THE AIM of the experiment to he described was to devise a method of producing artificial radioactivity and counter (constructed in a home laboratory). To determine what actually occurred when the transmutations with equipment available in high-school chromium was bombarded by alpha particles, an analyphysics and chemistry laboratories. A source of L'bullets" necessary to produce artificial sis was necessary. The chromium was dissolved in radioactivity or transmutations was obtained by bom- hydrochloric acid along with the product of bombardbarding lithium; in the form of lithium chloride, with ment. The resulting chlorides were then precipitated protons, thus securing relatively high energy alpha by ammonium hydroxide, filtered, and ignited in an particles. The alpha particles were used in turn to electric furnace. Hydrochloric acid added to the rebombard various elements to bring ahout artificial sulting oxides dissolved the product of bombardment. radioactivity. Protons were obtained by ionizing hy- The insoluble chromium oxide was filtered and a portion drogen gas a t low pressures with an incandescent fila- of the filtrate tested for iron with potassium thiocyament and accelerated by means of a demonstration nate. The test for iron showed positive. The remaining iron was then precipitated by ammonium hydroxide, static generator. The proton accelerator consisted of the outer tube of filtered, and the residue tested for radioactivity with a Liebig condenser with an incandescent filament sealed film and blueprint paper. The tests showed positive. Original samples of chromium were tested for radiointo the tube a few inches from one end. Sealed in each end was a metal plate with leads connecting to the activity and iron in the same manner as a control. A11 static generator. The negative plate contained the such tests showed negative. It appears from the information gathered that the lithium chloride and desired target. A glass tube was also sealed in one end, through which,the hydrogen was following reactions occurred within the accelerator: introduced (see Figure 1). aLi' + 91 ~He4+ 1He4 Dried hydrogen was allowed to enter the accelerator r r C P %He4 + &eS5 on1 through the glass tube and displace all the air in the &eFe" -+ K + 7 accelerator. After displacement of the air the glass tube was sealed off and a vacuum pump, connected a t A, set into operation. When the hydrogen was a t sufficiently -reduced pressure the filament was turned on and the static generator started. Proper polarity was insured by charging the generator with a lowvoltage (400 v.) power supply. The apparatus was allowed to operate from 20 to 30 minutes. In the original experiment chromium was used as a target. After bombardment the target was removed and tested for radioactivity. It caused sensitive vhotographic film and blueprint paper to appear light struck k-isuw 1. proton A ~ ~ I
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