Timothy Baldwin

TIARA: A large solid angle silicon array for direct reaction studies with radioactive beams

A compact, quasi-4pi position sensitive silicon array, TIARA, designed to study direct reactions induced by radioactive beams in inverse kinematics is described here. The Transfer and Inelastic All-angle Reaction Array (TIARA) consists of 8 resistive-strip silicon detectors forming an octagonal barrel around the target and a set of double-sided silicon-strip annular detectors positioned at each end of the barrel. The detector was coupled to the gamma-ray array EXOGAM and the spectrometer VAMOS at the GANIL Laboratory to demonstrate the potential of such an apparatus with radioactive beams. The 14N(d,p)15N reaction, well known in normal kinematics, has been carried out in inverse kinematics for that purpose. The observation of the 15N ground state and excited states at 7.16 and 7.86 MeV is presented here as well as the comparison of the measured proton angular distributions with DWBA calculations. Transferred l-values are in very good agreement with both theoretical calculations and previous experimental results obtained in normal kinematics.

Migration of Nuclear Shell Gaps Studied in the d(Ne-24, p gamma)Ne-25 Reaction

The transfer of neutrons onto 24Ne has been measured using a reaccelerated radioactive beam of 24Ne to study the (d,p) reaction in inverse kinematics. The unusual raising of the first 3/2+ level in 25Ne and its significance in terms of the migration of the neutron magic number from N=20 to N=16 is put on a firm footing by confirmation of this states identity. The raised 3/2+ level is observed simultaneously with the intruder negative parity 7/2- and 3/2- levels, providing evidence for the reduction in the N=20 gap. The coincident gamma-ray decays allowed the assignment of spins as well as the transferred orbital angular momentum. The excitation energy of the 3/2+ state shows that the established USD shell model breaks down well within the sd model space and requires a revised treatment of the proton-neutron monopole interaction.

{alpha}-decaying states in {sup 10,12}Be populated in the {sup 10}Be({sup 14}C,{sup 10,12}Be) reaction

A search has been made for the {sup 6}He+{sup 6}He and {alpha} + {sup 8}He decay of the molecular rotational band in {sup 12}Be using the {sup 10}Be({sup 14}C,{sup 12}Be*){sup 12}C reaction at 88.5 MeV. Although the {alpha} + {sup 6}He decay of {sup 10}Be was observed in the data set there is no evidence for the breakup of {sup 12}Be. The cross-section upper limits for the {sup 10}Be({sup 14}C,{sup 6}He {sup 6}He){sup 12}C and {sup 10}Be({sup 14}C,{alpha} {sup 8}He){sup 12}C reactions are 50 and 300 nb respectively.

Decay studies for states in {sup 9}Be up to 11 MeV: Insights into the n+{sup 8}Be and {alpha}+{sup 5}He cluster structure

An experiment was performed to study the

Decay path measurements for the 2.429 MeV state in {sup 9}Be: Implications for the astrophysical {alpha}+{alpha}+n reaction

^{9}\mathrm{Be}

Studies of the Single Particle Structure of Exotic Nuclei using Transfer Reactions

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Decay path measurements for the 2.429-MeV state in Be-9: Implications for the astrophysical alpha + alpha + n reaction

^{6}\mathrm{Li}

Decay studies for states in 9 Be up to 11 MeV: Insights into the n + 8 Be and α + 5 He cluster stucture

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First excited 1/2(+) state in B-9

^{6}\mathrm{Li}

Single particle structure of exotic nuclei with transfer reactions

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