Reduced γ–γ time walk to below 50 ps using the multiplexed-start and multiplexed-stop fast-timing technique with LaBr3(Ce) detectors

Abrupt shape transition at neutron number N=60 : B(E2) values in SrRégis1, Jolie2, Saed-Samii3 et al. 2017Phys. Rev. CSelf Cite342270View full textAdd to dashboardCite

“…This procedure generates two independent fast-timing-array time spectra depending on whether the decay transition of the γ feeder -γ decay cascade provided a stop signal (the delayed time spectrum) or a start signal (antidelayed) as described in more detail in Refs. [16][17][18]. According to the generalized centroid difference (GCD) method and assuming no background contributions, the measurement of the relative time shift between the centroids (first moment of a time distribution) of the delayed and the antidelayed time spectra of a γ -γ cascade provides the centroid difference and corresponds to [17]:…”

“…The mirror symmetry provides additional PRD data, e.g., PRD feeder (E feeder ) = 0, for a precise determination of the PRD(E γ ) curve [18]. Using a standard 152 Eu source and the neutron-capture reaction 48 Ti(n,γ ) 49 Ti, the PRD curve of the fast-timing array including the electronics setup has been determined for the energy region of 0.04-6.8 MeV [16].…”

Measurement of picosecond lifetimes in neutron-rich Xe isotopes

“…[31] to determine the g factors proved to be incorrect. With the new values of τ 2 + determined in this work, the following g factors are obtained: g( 140 Xe; 2 + ) = 0.56 (19) and g( 142 Xe; 2 + ) = 0.49 (9). These values are currently not reproduced by theory calculations (see Refs.…”

“…A detailed description of the PRD calibration procedure is given in Ref. [19]. The derived prompt response differences were fitted with the function:…”

“…To obtain the lifetime of the state, several analysis steps need to be done: (i) build the delayed (γ 1 → start and γ 2 → stop) and antidelayed (γ 2 → start and γ 1 → stop) time distributions by posing gates in the LaBr 3 (Ce) spectra, including the necessary amount of HPGe gates in order to ensure that the right nucleus is selected and determine the centroid difference of the two distributions; (ii) using the same reference γ 2 line, build delayed and antidelayed time distributions with a second LaBr 3 (Ce) gate on energies in the background around γ 1 ; (iii) fit the centroid differences of the time distributions between the reference line and the background energies and determine the centroid difference of the background at the energy of γ 1 by interpolation; (iv) determine the peak-to-background ratio ; (v) determine the prompt response difference of the γ -γ cascade using Eq. (8) via the transformation PRD = PRD(E γ 1 ) − PRD(E γ 2 ) [19].…”