Commissioning of a new photon detection system for charge radii measurements of neutron-deficient Ca

POSTER

Abstract

Calcium is unique for its possession of two stable isotopes of ``doubly magic" nuclei at proton and neutron numbers $(Z, N) = (20, 20)$ and $(20, 28)$. Recent charge radii measurements of neutron-rich calcium isotopes yielded an upward trend beyond current theoretical predictions [R. F. G. Ruiz et al., Nat. Phys. 12, 594 (2016)]. At the BECOLA facility at NSCL/MSU, Ca charge radii measurements will be extended to the neutron-deficient regime using collinear laser spectroscopy. A new photon detection system with an ellipsoidal reflector and a compound parabolic concentrator has been commissioned for the experiment. The system increases the signal-to-noise ratio by reducing background, which is critical for the low production rates of the Ca experiment. Details of the system and results of the characterization tests will be discussed.

*Work supported in part by NSF Grant PHY-15-65546, U.S. DOE grant DE-NA0002924 and by the Deutsche Forschungsgemeinschaft Grant SFB 1245

Authors

  • J. Watkins

    • NSCL, MSU/University of Washington

  • D. Garand

    • NSCL, MSU

  • A. J. Miller

    • NSCL/Dept. of Phys., MSU
    • NSCL/Dep. of Phys. and Astron., MSU

  • Kei Minamisono

    • NSCL/Dept. of Phys., MSU
    • NSCL/Dep. Phys. Astronomy, MSU

  • N. Everett

    • NSCL/Dept. of Phys., MSU

  • R. C. Powel

    • NSCL/Dept. of Phys., MSU

  • B. Maa\ss

    • TU Darmstadt

  • W. N{\"o}rtersh{\"a}user

    • TU Darmstadt

  • C. Kalman

    • NSCL/Dept. of Chem., MSU

  • J. Lantis

    • NSCL/Dept. of Chem., MSU

  • C. Kujawa

    • Dept. of Chem., Augustana University

  • P. Mantica

    • FRIB/Dept. of Chem., MSU