ENTRY C2651 20210713 C205C265100000001 SUBENT C2651001 20210713 C205C265100100001 BIB 10 60 C265100100002 TITLE Experiments on Antiprotons: Cross Sections of Complex C265100100003 Nuclei C265100100004 AUTHOR (L.E.Agnew,O.Chamberlain,D.V.Keller,R.Mermod, C265100100005 E.H.Rogers,H.M.Steiner,C.Wiegand) C265100100006 REFERENCE (J,PR,108,1545,1957) C265100100007 #doi:10.1103/PhysRev.108.1545 C265100100008 INSTITUTE (1USABRK,1USAUCX) C265100100009 FACILITY (SYNCH,1USABRK) Bevatron, a weak-focusing proton C265100100010 synchrotron. C265100100011 INC-SPECT The Bevatron beam incident upon the antiproton C265100100012 production target was in the energy range 5.8 to 6.3 C265100100013 GeV. The internal beam intensity was from 2*10**10 to C265100100014 3*10**10 protons per pulse, one pulse every 6 seconds. C265100100015 The production targets used were C or (CH2)n. C265100100016 DETECTOR (SCIN,CEREN) The velocity was determined by the use C265100100017 of Cherenkov counters that discriminated against pions C265100100018 but were sensitive to antiprotons. These counters C265100100019 consisted of liquid styrene radiators (index of C265100100020 refraction 1.543) viewed by one RCA-6810 C265100100021 photomultiplier tube. The annihilation events were C265100100022 separately detected in Counter C*, which was a C265100100023 Cherenkov counter containing methyl alcohol (index of C265100100024 refraction 1.33). C265100100025 METHOD (ASEP,COINC) The mass spectrograph, which gave a C265100100026 signal whenever an antiproton passed through it. The C265100100027 spectrograph contained several improvements that C265100100028 greatly increased the luminosity of the apparatus. C265100100029 This was accomplished by increasing the aperture of C265100100030 the spectroscope and, also, by accepting a momentum C265100100031 interval of 3% instead of only 1% as before. This C265100100032 relaxation of the momentum definition made the mass C265100100033 determination less precise, but once antiprotons had C265100100034 been identified, we could afford this uncertainty. C265100100035 Nuclear-emulsion studies of annihilations of C265100100036 antiprotons have shown that nearly all annihilations C265100100037 give rise to fast charged pions (fast enough to give C265100100038 detectable light in methyl alcohol) or neutral pions C265100100039 (whose gamma rays frequently are converted within C265100100040 Counter C* and give detectable Cherenkov radiation). C265100100041 Each antiproton indicated by the mass spectrograph C265100100042 was considered an annihilation if it was accompanied C265100100043 by a pulse in the C* counter, irrespective of whether C265100100044 counts were registered by other counters. If no pulse C265100100045 was seen in the C* counter, then the presence or C265100100046 absence of pulses in other counters indicated whether C265100100047 the antiproton in question passed through without C265100100048 scattering (actually, scattered to an angle smaller C265100100049 than 14.3 degrees), or scattered to an angle between C265100100050 14.3 and 20.5 degrees, or scattered to an angle C265100100051 greater than 20.5 degrees. C265100100052 ERR-ANALYS (ERR-S) The statistical errors in the determination C265100100053 of the cross sections are given by the formula dsigma C265100100054 thetac = (1/N)*[(1/(I thetac))-(1/(I0)) ]**0.5, C265100100055 where N is the thickness of the absorber in the slots C265100100056 in nuclei per square centimeter, I0 the number of C265100100057 incident particles, I thetac is the number of C265100100058 pass-through particles with a cutoff angle thetac. C265100100059 Some other systematic error will be shown by further C265100100060 experiments. C265100100061 HISTORY (20210713C) BP C265100100062 ENDBIB 60 0 C265100100063 NOCOMMON 0 0 C265100100064 ENDSUBENT 63 0 C265100199999 SUBENT C2651002 20210713 C205C265100200001 BIB 2 4 C265100200002 REACTION 1((8-O-0(AP,X)1-PN-0,,SIG)+(8-O-0(AP,X)1-PP-0,,SIG)+ C265100200003 (8-O-0(AP,X)0-P0-0,,SIG)) Annihilation cross section. C265100200004 2(8-O-0(AP,NON),,SIG) C265100200005 STATUS (TABLE) Table IV, page 550. C265100200006 ENDBIB 4 0 C265100200007 NOCOMMON 0 0 C265100200008 DATA 5 1 C265100200009 EN DATA 1ERR-S 1DATA 2ERR-S 2 C265100200010 MEV MB MB MB MB C265100200011 457.0 453.0 9.0 590.0 12.0 C265100200012 ENDDATA 3 0 C265100200013 ENDSUBENT 12 0 C265100299999 SUBENT C2651003 20210713 C205C265100300001 BIB 2 2 C265100300002 REACTION (8-O-0(P,NON),,SIG) C265100300003 STATUS (TABLE) Table IV, page 550. C265100300004 ENDBIB 2 0 C265100300005 NOCOMMON 0 0 C265100300006 DATA 3 1 C265100300007 EN DATA ERR-S C265100300008 MEV MB MB C265100300009 457.0 340.0 4.0 C265100300010 ENDDATA 3 0 C265100300011 ENDSUBENT 10 0 C265100399999 SUBENT C2651004 20210713 C205C265100400001 BIB 3 6 C265100400002 REACTION 1((29-CU-0(AP,X)1-PN-0,,SIG)+(29-CU-0(AP,X)1-PP-0,,SIG)+C265100400003 (29-CU-0(AP,X)0-P0-0,,SIG)) Annihilation cross section.C265100400004 2(29-CU-0(AP,NON),,SIG) C265100400005 SAMPLE Cu, 67 g/cm2 or 0.644*10**24 atoms/cm2. Mid-target C265100400006 beam energy 411 MeV. C265100400007 STATUS (TABLE) Table IV, page 550. C265100400008 ENDBIB 6 0 C265100400009 NOCOMMON 0 0 C265100400010 DATA 5 1 C265100400011 EN DATA 1ERR-S 1DATA 2ERR-S 2 C265100400012 MEV MB MB MB MB C265100400013 411.0 1040.0 61.0 1260.0 91.0 C265100400014 ENDDATA 3 0 C265100400015 ENDSUBENT 14 0 C265100499999 SUBENT C2651005 20210713 C205C265100500001 BIB 3 4 C265100500002 REACTION (29-CU-0(P,NON),,SIG) C265100500003 SAMPLE Cu, 67 g/cm2 or 0.644*10**24 atoms/cm2. Mid-target C265100500004 beam energy 411 MeV. C265100500005 STATUS (TABLE) Table IV, page 550. C265100500006 ENDBIB 4 0 C265100500007 NOCOMMON 0 0 C265100500008 DATA 3 1 C265100500009 EN DATA ERR-S C265100500010 MEV MB MB C265100500011 411.0 880.0 10.0 C265100500012 ENDDATA 3 0 C265100500013 ENDSUBENT 12 0 C265100599999 SUBENT C2651006 20210713 C205C265100600001 BIB 3 6 C265100600002 REACTION 1((47-AG-0(AP,X)1-PN-0,,SIG)+(47-AG-0(AP,X)1-PP-0,,SIG)+C265100600003 (47-AG-0(AP,X)0-P0-0,,SIG)) Annihilation cross section.C265100600004 2(47-AG-0(AP,NON),,SIG) C265100600005 SAMPLE Ag, 53 g/cm2 or 0.296*10**24 atoms/cm2. Mid-target C265100600006 beam energy 431 MeV. C265100600007 STATUS (TABLE) Table IV, page 550. C265100600008 ENDBIB 6 0 C265100600009 NOCOMMON 0 0 C265100600010 DATA 5 1 C265100600011 EN DATA 1ERR-S 1DATA 2ERR-S 2 C265100600012 MEV MB MB MB MB C265100600013 421.0 1500.0 157.0 1635.0 188.0 C265100600014 ENDDATA 3 0 C265100600015 ENDSUBENT 14 0 C265100699999 SUBENT C2651007 20210713 C205C265100700001 BIB 3 4 C265100700002 REACTION (47-AG-0(P,NON),,SIG) C265100700003 SAMPLE Ag, 53 g/cm2 or 0.296*10**24 atoms/cm2. Mid-target C265100700004 beam energy 431 MeV. C265100700005 STATUS (TABLE) Table IV, page 550. C265100700006 ENDBIB 4 0 C265100700007 NOCOMMON 0 0 C265100700008 DATA 3 1 C265100700009 EN DATA ERR-S C265100700010 MEV MB MB C265100700011 431.0 1170.0 12.0 C265100700012 ENDDATA 3 0 C265100700013 ENDSUBENT 12 0 C265100799999 SUBENT C2651008 20210713 C205C265100800001 BIB 3 6 C265100800002 REACTION 1((82-PB-0(AP,X)1-PN-0,,SIG)+(82-PB-0(AP,X)1-PP-0,,SIG)+C265100800003 (82-PB-0(AP,X)0-P0-0,,SIG)) Annihilation cross section.C265100800004 2(82-PB-0(AP,NON),,SIG) C265100800005 SAMPLE Pb, 58 g/cm2 or 0.1678*10**24 atoms/cm2. Mid-target C265100800006 beam energy 436 MeV. C265100800007 STATUS (TABLE) Table IV, page 550. C265100800008 ENDBIB 6 0 C265100800009 NOCOMMON 0 0 C265100800010 DATA 5 1 C265100800011 EN DATA 1ERR-S 1DATA 2ERR-S 2 C265100800012 MEV MB MB MB MB C265100800013 436.0 2010.0 182.0 3005.0 275.0 C265100800014 ENDDATA 3 0 C265100800015 ENDSUBENT 14 0 C265100899999 SUBENT C2651009 20210713 C205C265100900001 BIB 3 4 C265100900002 REACTION (82-PB-0(P,NON),,SIG) C265100900003 SAMPLE Pb, 58 g/cm2 or 0.1678*10**24 atoms/cm2. Mid-target C265100900004 beam energy 436 MeV. C265100900005 STATUS (TABLE) Table IV, page 550. C265100900006 ENDBIB 4 0 C265100900007 NOCOMMON 0 0 C265100900008 DATA 3 1 C265100900009 EN DATA ERR-S C265100900010 MEV MB MB C265100900011 436.0 1845.0 40.0 C265100900012 ENDDATA 3 0 C265100900013 ENDSUBENT 12 0 C265100999999 ENDENTRY 9 0 C265199999999