Lifetime measurement of the260 g.s. At SAMURAI

• Storck, S.
• Caesar, C.
• Kahlbow, J.
• Panin, V.
• Ahn, D. S.
• Atar, L.
• Aumann, T.
• Baba, H.
• Boretzky, K.
• Chae, H.
• Chiga, N.
• Choi, S.
• Cortés, M. L.
• Cortina-Gil, D.
• Deshayes, Q.
• Doornenbal, P.
• Elekes, Z.
• Fukuda, N.
• Gaparic, I.
• Hahn, K. I.
• Halász, Z.
• Hirayama, A.
• Inabe, N.
• Isobe, T.
• Kobayashi, T.
• Körper, D.
• Kondo, Y.
• Kubota, Y.
• Kuti, I.
• Lehr, C.
• Marques, M.
• Matsumoto, M.
• Murakami, T.
• Murray, I.
• Nakamura, T.
• Nilsson, T.
• Otsu, H.
• Paschalis, S. https://orcid.org/0000-0002-9113-3778
• Parlog, M.
• Petri, M. https://orcid.org/0000-0002-3740-6106
• Rossi, D.
• Saito, A.
• Sasano, M.
• Scheit, H.
• Schrock, P.
• Shimizu, Y.
• Simon, H.
• Sohler, D.
• Sorlin, O.
• Stuhl, L.
• Suzuki, H.
• Syndikus, I. (is753@york.ac.uk)
• Takeda, H.
• Törnqvist, H.
• Togano, Y.
• Tomai, T.
• Uesaka, T.
• Yamada, H.
• Yang, Z.
• Yasuda, M.
• Yoneda, K. I.

Funding Information: The incoming beam is identified using the ionization chamber (ICB) and tracked with the drift chambers (BDC 1 & 2 ). The time-of-flight measurement is initiated by the plastic scintillators SBT 1 & 2. The target was surrounded by three 300 µm thick single-area silicon detectors. Those are necessary to identify the incoming beam particles directly in front of the target and the fragments after the proton removal reaction to select the isotope of interest. One silicon detector was installed in front of the target stack and two behind. The target in which the reaction happened can already be identified in the ∆ν-spectrum, which makes it unnecessary to measure the energy loss between the individual target sheets. The silicon detectors act as targets themselves and therefore contribute to the background as indicated by the gray peaks in Fig. 4. The background originating from the silicon detectors can not easily be determined by an empty target run since the energy loss from the target would be missing and the peaks of the individual silicon detectors would overlap in the ∆ν-spectrum. However, the background contributions can be determined from a reference measurement with the 26F secondary beam where 25O is produced from proton removal but no lifetime is expected (τ < 10−21s) and thus a flat spectrum. The secondary beam 24O, with 210 MeV/u and a rate of ∼ 1000 cps, is very sharp in energy and and high intensity 48Ca primary beam and the BigRIPS team for their efforts in preparing the secondary beams. This work has been supported by DFG grant no. SFB 1245, BMBF contract 05P15RDFN1 and GSI-TU Darmstadt cooperation agreement. Publisher Copyright: © 2020 Institute of Physics Publishing. All rights reserved.

• Published: 23 December 2020

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