ENTRY C3073 20250624 C307300000001 SUBENT C3073001 20250624 20251001 C307300100001 BIB 11 40 C307300100002 TITLE First Measurement of 87Rb(alpha,xn) Cross Sections at C307300100003 Weak r-process Energies in Supernova neutrino-driven C307300100004 Ejecta to Investigate Elemental Abundances in C307300100005 Low-metallicity Stars C307300100006 AUTHOR (C.Fougeres,M.L.Avila,A.Psaltis,M.Anastasiou,S.Bae, C307300100007 L.Balliet,K.Bhatt,L.Dienis,H.Jayatissa,V.Karayonchev, C307300100008 P.Mohr,F.Montes,D.Neto,F.De Oliveira Santos,W.-J.Ong, C307300100009 K.E.Rehm,W.Reviol,D.Santiago-Gonzalez,N.Sensharma, C307300100010 R.S.Sidhu,I.A.Tolstukhin) C307300100011 REFERENCE (J,AJ,983,142,2025) C307300100012 #doi:10.3847/1538-4357/adc253 C307300100013 INSTITUTE (1USAANL,2FR BRC,2FR SAC,1USADKE,1USALRL,3KORIBS, C307300100014 1USAMSU,2FR GAN,1USALAS,3HUNDEB,2UK SUR) C307300100015 (1USAUSA) Department of Physics, University of C307300100016 Illinois Chicago, 845 W. Taylor St., Chicago, IL C307300100017 60607, USA C307300100018 FACILITY (LINAC,1USAANL) The Argonne Tandem Linac Accelerator C307300100019 System (ATLAS). C307300100020 INC-SPECT The 87Rb stable beam delivered by the ATLAS had a C307300100021 charge state of 17+, an energy of 4.61(1) MeV/u, and C307300100022 an average intensity of 3.7 x 104 pps. C307300100023 DETECTOR (IOCH,SIBAR) The active target MUlti-Sampling C307300100024 Ionization Chamber (MUSIC). C307300100025 SAMPLE The MUSIC detector was filled with pure 4He gas at C307300100026 555 Torr held by Ti foils of 1.30(5) mg cm-2 C307300100027 thickness at the entrance and exit sides for the beam. C307300100028 METHOD (EDE) With electrically segmented (stripped) C307300100029 detectors in a single direction, the search for C307300100030 (alpha,xn) events may follow in steps: 1) The PID C307300100031 method - a global analysis that looks at energy C307300100032 losses summed over several strips dE - Etotal, similar C307300100033 to the Particle IDentification (PID) with silicon C307300100034 detectors and their variants. The PID method was C307300100035 first employed to identify (alpha,xn) and scattering C307300100036 events, which occurred in each strip of the MUSIC C307300100037 detector. 2) The Traces method - a local analysis C307300100038 that tracks energy loss per strip. Then, the Traces C307300100039 method was used to count (alpha,xn) events. C307300100040 STATUS (APRVD) Approved by C.Fougeres on June 27, 2025. C307300100041 HISTORY (20250624C) BP C307300100042 ENDBIB 40 0 C307300100043 NOCOMMON 0 0 C307300100044 ENDSUBENT 43 0 C307300199999 SUBENT C3073002 20250624 20251001 C307300200001 BIB 4 20 C307300200002 REACTION (((2-HE-4(37-RB-87,N)39-Y-90,,SIG)+ C307300200003 (2-HE-4(37-RB-87,2N)39-Y-89,,SIG))= C307300200004 ((37-RB-87(A,N)39-Y-90,,SIG)+ C307300200005 (37-RB-87(A,2N)39-Y-89,,SIG))) C307300200006 ERR-ANALYS (DATA-ERR) Horizontal (energy) uncertainties of the C307300200007 measured cross sections correspond to the spatial C307300200008 extension of the strip, and vertical uncertainties C307300200009 include both statistical and systematic contributions. C307300200010 (ERR-S) Statistical uncertainties. C307300200011 (ERR-SYS) Systematic uncertainties comprise the C307300200012 impact of independently varying the conditions C307300200013 applied in the analysis to select the 87Rb beam and C307300200014 identify (alpha,xn) events as well as the uncertainty C307300200015 in the gas pressure (1 Torr). C307300200016 CORRECTION To determine the center-of-mass energies deduced from C307300200017 the measurement of the beam energy losses in the C307300200018 MUSIC detector were corrected for the thick-target C307300200019 yield. C307300200020 STATUS (TABLE,,C.Fougeres+,J,AJ,983,142,2025) Table 2 C307300200021 Data were provided by C.Fougeres on June 26, 2025. C307300200022 ENDBIB 20 0 C307300200023 NOCOMMON 0 0 C307300200024 DATA 7 10 C307300200025 EN-CM -EN-RSL +EN-RSL DATA-CM DATA-ERR ERR-S C307300200026 ERR-SYS C307300200027 MEV MEV MEV MB MB PER-CENT C307300200028 PER-CENT C307300200029 8.09 0.39 0.18 0.92 0.31 25.C307300200030 23.6 C307300200031 8.66 0.39 0.18 3.77 0.66 12.3C307300200032 12.4 C307300200033 9.22 0.38 0.19 10.7 1.0 7.24C307300200034 6.18 C307300200035 9.77 0.36 0.21 32.9 2.0 4.08C307300200036 4.62 C307300200037 10.32 0.33 0.22 67.4 3.8 2.81C307300200038 4.87 C307300200039 10.87 0.33 0.22 109. 6. 2.19C307300200040 5.40 C307300200041 11.41 0.32 0.23 192. 8. 1.62C307300200042 4.32 C307300200043 11.94 0.30 0.25 291. 11. 1.28C307300200044 3.71 C307300200045 12.49 0.30 0.24 355. 19. 1.13C307300200046 5.37 C307300200047 13.01 0.28 0.26 420. 17. 1.01C307300200048 3.95 C307300200049 ENDDATA 24 0 C307300200050 ENDSUBENT 49 0 C307300299999 ENDENTRY 2 0 C307399999999