TY - JOUR

T1 - NON-SPIN-FLIP (HE-3, T) CHARGE-EXCHANGE AND ISOBARIC ANALOG STATES OF ACTINIDE NUCLEI STUDIED AT THETA=0-DEGREES, E(HE-3)=76 MEV AND 200 MEV

AU - JANECKE, J

AU - BECCHETTI, FD

AU - VANDENBERG, AM

AU - BERG, GPA

AU - GREENFIELD, MB

AU - HARAKEH, MN

AU - HOFSTEE, MA

AU - NADASEN, A

AU - ROBERTS, DA

AU - SAWAFTA, R

AU - SCHIPPERS, JM

AU - STEPHENSON, EJ

AU - STEWART, DP

AU - VANDERWERF, SY

PY - 1991/4/22

Y1 - 1991/4/22

N2 - The (He-3, t) charge-exchange reaction has been studied at theta = 0-degree-C and bombarding energies of E(He-3) = 76.5 MeV and 200 MeV. Spectra were measured using magnetic analysis for target nuclei of C-12, C-13, O-16, F-19, Si-28, Si-29, Si-30, Zr-90, Sn-117, Sn-120, (nat)Ta, (nat)W, Au-197, Pb-208, Th-230, Th-232, U-234, U-236, U-238 and Pu-244. The measurements at 76.5 MeV concentrated on the isobaric analog states of several actinide nuclei, particularly on their widths and the branching ratios for proton decay. Cross sections, Q-values and total widths were determined for the transitions to the isobaric analog states. Coulomb displacement energies derived from the measured Q-values display the influence of deformed nuclear shapes. Escape widths GAMMA-up and spreding widths GAMMA-down of the isobaric analog states in five actinide nuclei were deduced from the measured proton-decay branching ratios. They were found to be in agreement with predictions which postulate isospin mixing via the Coulomb force with the (T0-1)-component of the isovector giant monopole resonance. The measurements at 200 MeV were concerned with transitions to isobaric analog states in both light and heavy nuclei, including several actinide nuclei, but Gamow-Teller resonances and transitions to numerous other states were also observed. The measured cross sections for several transitions to isobaric analog states from Si-30 to Pb-208 were used to extract the effective interaction V(tau) for non-spin-flip (He-3, t) charge exchange at E(He-3) almost-equal-to 200 MeV. The interaction strength V(tau) decreases by a factor 0.6 when compared to previously measured values for the energy range E(He-3) = 65 to 90 MeV. An angular distribution from theta(t) = 0-degree to 16-degrees for the transition to the isobaric analog state in Sb-120 measured at E(He-3) = 200 MeV was found to be in very good agreement with microscopic calculations.

AB - The (He-3, t) charge-exchange reaction has been studied at theta = 0-degree-C and bombarding energies of E(He-3) = 76.5 MeV and 200 MeV. Spectra were measured using magnetic analysis for target nuclei of C-12, C-13, O-16, F-19, Si-28, Si-29, Si-30, Zr-90, Sn-117, Sn-120, (nat)Ta, (nat)W, Au-197, Pb-208, Th-230, Th-232, U-234, U-236, U-238 and Pu-244. The measurements at 76.5 MeV concentrated on the isobaric analog states of several actinide nuclei, particularly on their widths and the branching ratios for proton decay. Cross sections, Q-values and total widths were determined for the transitions to the isobaric analog states. Coulomb displacement energies derived from the measured Q-values display the influence of deformed nuclear shapes. Escape widths GAMMA-up and spreding widths GAMMA-down of the isobaric analog states in five actinide nuclei were deduced from the measured proton-decay branching ratios. They were found to be in agreement with predictions which postulate isospin mixing via the Coulomb force with the (T0-1)-component of the isovector giant monopole resonance. The measurements at 200 MeV were concerned with transitions to isobaric analog states in both light and heavy nuclei, including several actinide nuclei, but Gamow-Teller resonances and transitions to numerous other states were also observed. The measured cross sections for several transitions to isobaric analog states from Si-30 to Pb-208 were used to extract the effective interaction V(tau) for non-spin-flip (He-3, t) charge exchange at E(He-3) almost-equal-to 200 MeV. The interaction strength V(tau) decreases by a factor 0.6 when compared to previously measured values for the energy range E(He-3) = 65 to 90 MeV. An angular distribution from theta(t) = 0-degree to 16-degrees for the transition to the isobaric analog state in Sb-120 measured at E(He-3) = 200 MeV was found to be in very good agreement with microscopic calculations.

KW - C-12, O-16, AL-27, SI-28, TA, TH-230, TH-232, U-234, U-236, U-238,

KW - (HE-3,T), E=76.5 MEV C-12, C-13, O-16, F-19, SI-28, ZR-90, SN-117,

KW - SN-120, TA, W, AU-197, PB-208, TH-230, TH-232, U-234, U-238, PU-244,

KW - (HE-3,T), E=200 MEV

KW - MEASURED SIGMA (ET) THETA=0-DEGREES

KW - SN-120 (HE-3,T), E=200 MEV

KW - MEASURED SIGMA(THETA-T) FOR ISOBARIC ANALOG STATE (IAS),

KW - THETA-T=0-DEGREES TO 16-DEGREES

KW - TH-230, TH-232, U-234, U-236, U-238 (HE-3,TP), E=76.5 MEV

KW - MEASURED PROTON DECAY FROM IAS, THETA(ET, EP, THETA-T,

KW - THETA-P) FOR THETA-T=0-DEGREES, THETA-P=+120-DEGREES, +150-

KW - DEGREES, -150-DEGREES

KW - DEDUCED Q-VALUES FOR TRANSITIONS TO IAS, NB-90, SB-117, SN-120,

KW - W-181, RE-184, HG-197, PB-208, PA-230, PA-232, NP-234, NP-236,

KW - NP-238, AM-244, COULOMB DISPLACEMENT ENERGIES, TOTAL WIDTHS

KW - GAMMA, ESCAPE WIDTHS GAMMA-UP, SPREADING WIDTHS GAMMA-DOWN

KW - OF IAS, PB-208, PA-230, PA-232, NP-234, NP-236, NP-238, AM-244

KW - EFFECTIVE INTERACTION V-TAU FOR NON-SPIN-FLIP CHARGE EXCHANGE

KW - TRANSITIONS TO IAS, P-30, NB-90, SN-120, PB-208

KW - ENRICHED AND LONG-LIVED RADIOACTIVE TARGETS

KW - MAGNETIC SPECTROMETERS

KW - ISOVECTOR GIANT-RESONANCES

KW - COULOMB DISPLACEMENT ENERGIES

KW - MONOPOLE RESONANCE

KW - INTERMEDIATE ENERGIES

KW - = 0-DEGREES

KW - DECAY

KW - DEPENDENCE

KW - MODEL

KW - LIGHT

KW - PROBABILITY

M3 - Article

VL - 526

SP - 1

EP - 35

JO - Nuclear Physics A

JF - Nuclear Physics A

SN - 0375-9474

IS - 1

ER -