Abstract
The TIGRESS Integrated Plunger device (TIP) has been developed for recoil distance method (RDM) lifetime measurements using the TIGRESS array of HPGe γ-ray detectors at TRIUMF's ISAC-II facility. A commissioning experiment was conducted utilizing a 250 MeV 84Kr beam at ≈2×108 particles per second. The 84Kr beam was Coulomb excited to the 21+ state on a movable 27Al target. A thin Cu foil fixed downstream from the target was used as a degrader. Excited nuclei emerged from the target and decayed by γ-ray emission at a distance determined by their velocity and the lifetime of the 21+ state. The ratio of decays which occur between the target and degrader to those occurring after traversing the degrader changes as a function of the target–degrader separation distance. Gamma-ray spectra at 13 target–degrader separation distances were measured and compared to simulated lineshapes to extract the lifetime. The result of τ=5.541±0.013(stat.)±0.063(sys.) ps is shorter than the literature value of 5.84±0.18 ps with a reduction in uncertainty by a factor of approximately two. The TIP plunger device, experimental technique, analysis tools, and result are discussed.
Original language | English (US) |
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Pages (from-to) | 69-83 |
Number of pages | 15 |
Journal | Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment |
Volume | 882 |
DOIs | |
State | Published - Feb 21 2018 |
Funding
The authors would like to acknowledge the support of the ISAC Operations Group and Detector Group at TRIUMF , and the Simon Fraser University Electronics and Machine Shops . The Coulex angular correlation work benefited from many discussions with Dr. Ching-Yen Wu; the authors are grateful for his input and advice. This work was supported by the Natural Sciences and Engineering Research Council of Canada award SAPIN/371656-2015 . This work has been supported by the Natural Sciences and Engineering Research Council of Canada , The Canada Foundation for Innovation , and the British Columbia Knowledge Development Fund . TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada.
Keywords
- Coulomb excitation
- CsI(Tl) pulse shape analysis
- Doppler-shift lifetime methods
- Gamma-ray spectroscopy
- Monte Carlo analysis
ASJC Scopus subject areas
- Nuclear and High Energy Physics
- Instrumentation