ENTRY C2534 20200607 C196C253400000001 SUBENT C2534001 20200607 C196C253400100001 BIB 7 13 C253400100002 TITLE Search of Superheavy Elements Produced in the 136Xe + C253400100003 238U Reaction and an Upper Limit Cross Section for C253400100004 the natGd(136Xe,X)212Pb Reaction C253400100005 AUTHOR (R.J.Otto,A.Ghiorso,D.Lee,R.E.Leber,S.Yashita, C253400100006 G.T.Seaborg) C253400100007 REFERENCE (J,RCA,24,3,1977) C253400100008 #doi:10.1524/ract.1977.24.1.3 C253400100009 (R,LBL-7104,1977) Same as Radiochim.Acta 24,3,1977 C253400100010 INSTITUTE (1USABRK) C253400100011 FACILITY (LINAC,1USABRK) The heavy ion linear accelerator C253400100012 (HILAC). C253400100013 METHOD (ACTIV) C253400100014 HISTORY (20200607C) BP C253400100015 ENDBIB 13 0 C253400100016 COMMON 2 3 C253400100017 EN EN-ERR C253400100018 MEV MEV C253400100019 1150.0 50.0 C253400100020 ENDCOMMON 3 0 C253400100021 ENDSUBENT 20 0 C253400199999 SUBENT C2534002 20200607 C196C253400200001 BIB 6 24 C253400200002 REACTION (92-U-238(54-XE-136,X)86-RN-211,,SIG) C253400200003 SAMPLE The target was a 19-mm disc of natural uranium, C253400200004 0.25-mm thick. The range of 136Xe from the surface of C253400200005 2 the target to the reaction barrier was taken to be C253400200006 17 mg/cm2 for all of the Xe + U experiments. C253400200007 DETECTOR (SIBAR) A 300-mm area gold surface barrier detector. C253400200008 METHOD (CHSEP,ASPEC) Following the experiment the target was C253400200009 dissolved in a 10 ml solution of 2 M HCl containing 1 C253400200010 ml of 30% H2O2. The solution was prefiltered to C253400200011 remove undissolved carbon deposits that formed on the C253400200012 surface of the target during the irradiation. The C253400200013 sample was briefly counted for alpha particle C253400200014 activity to check the thickness of the precipitate. C253400200015 These samples were pulse height analyzed continuously C253400200016 for spontaneous fission and alpha events for C253400200017 approximately 200 days. The noble gas fraction was C253400200018 obtained following irradiations of 0. 25-mm x 16-mm C253400200019 diameter natural uranium metal targets. After the C253400200020 heavy-ion irradiations the targets were placed in a C253400200021 sidearm flask which was connected with Tygon tubing C253400200022 to a calcium sulfate trying tube followed by a cold C253400200023 activated charcoal trap. C253400200024 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. C253400200025 STATUS (TABLE) Page 4, Radiochim.Acta 24,3,1977 C253400200026 ENDBIB 24 0 C253400200027 NOCOMMON 0 0 C253400200028 DATA 2 1 C253400200029 DATA DATA-ERR C253400200030 MB MB C253400200031 0.7 0.2 C253400200032 ENDDATA 3 0 C253400200033 ENDSUBENT 32 0 C253400299999 SUBENT C2534003 20200607 C196C253400300001 BIB 5 16 C253400300002 REACTION (64-GD-160(54-XE-136,X)82-PB-212,,SIG) C253400300003 SAMPLE Six pieces of 99.9% pure natural gadolinium metal C253400300004 (21.9% 160Gd) were milled and fitted to make a C253400300005 collimator with a 0.035-mm diameter aperture. C253400300006 METHOD (CHSEP,ASPEC) Three of the six gadolinium pieces were C253400300007 placed in a nitric acid solution and the active C253400300008 surface was dissolved. A search was made for 8.78 MeV C253400300009 alpha particles from the 212Po daughter of 10.2 hr C253400300010 212Pb. No alpha particle events were observed with C253400300011 energies above 7.45 MeV in over 16 hours of counting. C253400300012 This corresponds to an upper limit cross section of C253400300013 2x10**-34 cm2 for the production of 212Pb in the C253400300014 136Xe + natGd reaction, and 1 x l0**-33 cm2 136Xe + C253400300015 160Gd. for the Xe + Gd react1on. C253400300016 DECAY-DATA (82-PB-212,10.2HR,B-) C253400300017 STATUS (TABLE) Page 6, Radiochim.Acta 24,3,1977 C253400300018 ENDBIB 16 0 C253400300019 NOCOMMON 0 0 C253400300020 DATA 1 1 C253400300021 DATA-MAX C253400300022 NB C253400300023 1.0 C253400300024 ENDDATA 3 0 C253400300025 ENDSUBENT 24 0 C253400399999 SUBENT C2534004 20200607 C196C253400400001 BIB 5 16 C253400400002 REACTION (64-GD-0(54-XE-136,X)82-PB-212,,SIG) C253400400003 SAMPLE Six pieces of 99.9% pure natural gadolinium metal C253400400004 (21.9% 160Gd) were milled and fitted to make a C253400400005 collimator with a 0.035-mm diameter aperture. C253400400006 METHOD (CHSEP,ASPEC) Three of the six gadolinium pieces were C253400400007 placed in a nitric acid solution and the active C253400400008 surface was dissolved. A search was made for 8.78 MeV C253400400009 alpha particles from the 212Po daughter of 10.2 hr C253400400010 212Pb. No alpha particle events were observed with C253400400011 energies above 7.45 MeV in over 16 hours of counting. C253400400012 This corresponds to an upper limit cross section of C253400400013 2x10**-34 cm2 for the production of 212Pb in the C253400400014 136Xe + natGd reaction, and 1 x l0**-33 cm2 136Xe + C253400400015 160Gd. for the Xe + Gd react1on. C253400400016 DECAY-DATA (82-PB-212,10.2HR,B-) C253400400017 STATUS (TABLE) Page 6, Radiochim.Acta 24,3,1977 C253400400018 ENDBIB 16 0 C253400400019 NOCOMMON 0 0 C253400400020 DATA 1 1 C253400400021 DATA-MAX C253400400022 NB C253400400023 0.2 C253400400024 ENDDATA 3 0 C253400400025 ENDSUBENT 24 0 C253400499999 SUBENT C2534005 20200607 C196C253400500001 BIB 3 18 C253400500002 REACTION (92-U-238(54-XE-136,X)110-DS-290,,SIG) C253400500003 ANALYSIS By making a comparison of the 136Xe + 160Gd and 136Xe C253400500004 + 238U reaction to make 212Pb and 290Ds, respectively, C253400500005 it can be seen that both reactions require the C253400500006 transfer of 18 protons and 34 + n neutrons. Since C253400500007 both irradiations were thick target experiments and C253400500008 include projectile energies from 1150 MeV to the C253400500009 barrier, there would have been transfer product C253400500010 nuclei heavier than the target from both reactions C253400500011 having the same excitation energies and corresponding C253400500012 to the same number of protons and neutrons C253400500013 transferred. Based on this result an argument is C253400500014 given that the upper limit cross section for the C253400500015 production of 290Ds in the 136Xe + 238U reaction is C253400500016 4xl0**-36 cm2. C253400500017 STATUS (DEP,C2534002) C253400500018 (DEP,C2534003) C253400500019 (TABLE) Page 6, Radiochim.Acta 24,3,1977 C253400500020 ENDBIB 18 0 C253400500021 NOCOMMON 0 0 C253400500022 DATA 1 1 C253400500023 DATA-MAX C253400500024 PB C253400500025 4.0 C253400500026 ENDDATA 3 0 C253400500027 ENDSUBENT 26 0 C253400599999 ENDENTRY 5 0 C253499999999