Mallaburn, MJ, Singh, BS Nara, Cullen, DM, Hodge, D, Taylor, MJ, Giles, MM, Barber, L, Nita, CR, Mihai, RE, Mihai, C et al (show 31 more authors)
(2019)
A time-of-flight correction procedure for fast-timing data of recoils with varying implantation positions at a spectrometer focal plane.
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 933.
pp. 18-29.
Abstract
Fast-timing measurements at the focal plane of a separator can suffer from poor timing resolution. This is due to the variations in time-of-flight (ToF) for photons travelling to a given detector, which arise from the changes in the implantation positions of the recoil nuclei emitting the γ rays of interest. In order to minimise these effects on timing measurements, a procedure is presented that improves fast-timing data by performing ToF corrections on an event-by-event basis. This method was used to correct data collected with an array of eight LaBr3 detectors, which detected γ rays from spatially distributed 138Gd recoil-implants at the focal plane of the Recoil-Ion-Transport-Unit (RITU) spectrometer. The Generalised Centroid Difference (GCD) method was used to extract a lifetime from data in conjunction with a new procedure to calibrate the time walk. The lifetime of the first 2+ state in 138Gd, populated by the decay of the Kπ=8− isomeric state, was measured to be 229(24) ps using the ToF-corrected data, which is consistent within three standard deviations to the literature value. The results together with Monte-Carlo simulations show that the ToF correction procedure reduced the uncertainty in the measured lifetimes by 3 % in the case of the spatially distributed nuclei at the focal plane of RITU. However, ∼12 % has been estimated for a similar experiment when using a larger focal plane i.e. the Super-FRS at the FAIR facility.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Gd-138, Nuclear-state lifetimes, Fast-timing, Distributed source, Generalised-centroid-difference method, LaBr3 detectors |
| Depositing User: | Symplectic Admin |
| Date Deposited: | 04 Dec 2019 14:56 |
| Last Modified: | 19 Jan 2023 00:17 |
| DOI: | 10.1016/j.nima.2019.04.019 |
| Open Access URL: | https://doi.org/10.1016/j.nima.2019.04.019 |
| Related URLs: | |
| URI: | https://livrepository.liverpool.ac.uk/id/eprint/3064798 |
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