ENTRY C2402 20190710 C186C240200000001 SUBENT C2402001 20190710 C186C240200100001 BIB 11 39 C240200100002 TITLE Nuclear Transformations Produced in Copper by C240200100003 Alpha-Particle Bombardment C240200100004 AUTHOR (W.B.Mann) C240200100005 REFERENCE (J,PR,52,405,1937) C240200100006 #doi:10.1103/PhysRev.52.405 C240200100007 INSTITUTE (1USABRK) C240200100008 FACILITY (CYCLO,1USABRK) The cyclotron in the Radiation C240200100009 Laboratory at the University of California. C240200100010 SAMPLE 0.0001 in. thick copper foils. C240200100011 DETECTOR Cloud or Wilson chamber. C240200100012 METHOD (ACTIV) Measurements were made for the purpose of C240200100013 determining the excitation function of copper. A C240200100014 preliminary experiment was made in which a pile of C240200100015 ten copper foils, each 0.0001 in. thick, were exposed C240200100016 so that the alpha-particle beam fell normally on the C240200100017 first foil. Only the first five foils were found to C240200100018 be active. A second experiment was performed with C240200100019 five 0.0001 in. copper foils and the activities were C240200100020 followed on an electroscope for 35 hours. The C240200100021 stopping power of the foils was determined by C240200100022 observing visually the decrease in range of the C240200100023 alpha-particle beam in air on introducing the five C240200100024 foils into its path. The range was found to be C240200100025 decreased by 5 cm and, accordingly, it was assumed C240200100026 that each foil was equivalent to 1 cm of air. The C240200100027 range of the beam in air was 11.5 cm. C240200100028 CORRECTION The results for the short and long periods were C240200100029 corrected to infinite bombardment (after twenty C240200100030 minutes bombardment the first foil showed initial C240200100031 activities of 1.5 and 0.165 electroscope divisions C240200100032 per second for the short and long periods, C240200100033 respectively). C240200100034 COMMENT Compiler's comment: the original mean alpha particle C240200100035 range in cm of air was converted to energy using the C240200100036 classical assumption of 1 MeV per cm. It is C240200100037 reproducing 11 MeV cyclotron energy well. This C240200100038 article represents one of the first activation C240200100039 experiments associated with Professor J.R. Oppenheimer.C240200100040 HISTORY (20190710C) BP C240200100041 ENDBIB 39 0 C240200100042 NOCOMMON 0 0 C240200100043 ENDSUBENT 42 0 C240200199999 SUBENT C2402002 20190710 C186C240200200001 BIB 3 3 C240200200002 REACTION (29-CU-0(A,X)31-GA-68,,SIG,,REL) C240200200003 DECAY-DATA (31-GA-68,1.1HR,B+) C240200200004 STATUS (CURVE) Fig. 5, page 407. C240200200005 ENDBIB 3 0 C240200200006 NOCOMMON 0 0 C240200200007 DATA 2 5 C240200200008 EN DATA C240200200009 MEV ARB-UNITS C240200200010 6.999 0.346 C240200200011 8.004 1.114 C240200200012 8.983 2.711 C240200200013 10.007 5.115 C240200200014 10.997 7.727 C240200200015 ENDDATA 7 0 C240200200016 ENDSUBENT 15 0 C240200299999 SUBENT C2402003 20190710 C186C240200300001 BIB 3 3 C240200300002 REACTION (29-CU-0(A,X)31-GA-66,,SIG,,REL) C240200300003 DECAY-DATA (31-GA-66,9.2HR,B+) C240200300004 STATUS (CURVE) Fig. 5, page 407. C240200300005 ENDBIB 3 0 C240200300006 NOCOMMON 0 0 C240200300007 DATA 2 4 C240200300008 EN DATA C240200300009 MEV ARB-UNITS C240200300010 8.005 0.399 C240200300011 8.997 1.790 C240200300012 9.998 4.032 C240200300013 10.999 6.644 C240200300014 ENDDATA 6 0 C240200300015 ENDSUBENT 14 0 C240200399999 ENDENTRY 3 0 C240299999999