Study Of The Key Reaction ¹⁴O??,p?¹⁷F In X-ray Bursts Using A Gas Thick-target Technique

X-ray bursts are the most frequently observed thermonuclear explosions in nature.The ¹⁴O?a,p?¹⁷F reaction plays a critical role in burst models.According to the theoretical study of X-ray bursts,¹⁴O?a,p?¹⁷F reaction is an important reaction in the?p-process.The sensitivity of reaction rates has a prominent impact on the X-ray burst light curve.However,the reliable and precise reaction rates are very difficult to be obtained because of the large discrepancy between different measurements.So far,the ¹⁴O?a,p?¹⁷F reaction rate used in XRB models is based on an old experimental data.To obtain more precise reaction rate,the experimental study of ¹H(¹⁷F,a)¹⁴O,which is the inverse of the ¹⁴O?a,p?¹⁷F reaction,has been carried out.The key reaction ¹⁴O??,p?¹⁷F was investigated by measuring the cross section of¹H(¹⁷F,a)¹⁴O using thick-target technique in this thesis.The experiment was performed using the CNS radioactive ion beam separator?CRIB?,located at the Center for Nuclear Study?CNS?the University of Tokyo.The secondary 3.64 MeV/u ¹⁷F beam was produced via the transfer reaction of ²H(¹⁶O,n)¹⁷F with the energy 6.64 MeV/u.The ¹⁷F beam was separated and purified by CRIB and bombarded a thick hydrogen gas target.The energy spectra of the recoilingaparticles were measured by three?35?E-E silicon telescopes at different angles?3°,10°and 18°?.Further background measurement was conducted at RIBLL1?Radioactive Ion Beam Line in Lanzhou?.The reaction cross sections of ¹⁷F?p,a?¹⁴O have been derived in the energy range E_c.m.=2.7-3.4 MeV via the kinematics reconstruction.The results indicate that our experimental data are consistent with the previous ones in the energy region of E_c.m.>3 MeV.In the energy region of E_c.m.<3 MeV,our results are inconsistent with the previous ones and tend to support the theoretical prediction of destructive interference between the direct and resonant reaction.The cross section of ¹⁴O??,p₀?¹⁷F has been determined from detailed balance,and the astrophysical reaction rates have been calculated based on the known cross section data.The present reaction rates and the resonant ones were in a good agreement.