Abstract
We review major experiments and results obtained by the on-line low temperature nuclear orientation method at the NICOLE facility at ISOLDE, CERN since the year 2000 and highlight their general physical impact. This versatile facility, providing a large degree of controlled nuclear polarization, was used for a long-standing study of magnetic moments at shell closures in the region Z = 28, N = 28–50 but also for dedicated studies in the deformed region around A ∼ 180. Another physics program was conducted to test symmetry in the weak sector and constrain weak coupling beyond V–A. Those two programs were supported by careful measurements of the involved solid state physics parameters to attain the full sensitivity of the technique and provide interesting interdisciplinary results. Future plans for this facility include the challenging idea of measuring the beta–gamma–neutron angular distributions from polarized beta delayed neutron emitters, further test of fundamental symmetries and obtaining nuclear structure data used in medical applications. The facility will also continue to contribute to both the nuclear structure and fundamental symmetry test programs.
Highlights
A facility for ‘Nuclear Implantation into Cold On-Line Equipment’ (NICOLE) was installed at the on-line isotope separator ISOLDE 3 at CERN in 1988
The angular distribution is determined by nuclear parameters such as ground state spin, electromagnetic moments and the multipolarity of emitted radiation, as well as by the solid state properties of the implant in the host lattice, including the hyperfine field, the electric field gradient and the spin-lattice relaxation time
The detection of an irregular E2 admixture to the regular, mixed M2/E3 multipolarity of the 501 keV transition, deduced from the forward–backward asymmetry of its angular distribution, reported in earlier nuclear orientation studies, has for decades stood as the prime evidence for parity mixing in nuclear states
Summary
A facility for ‘Nuclear Implantation into Cold On-Line Equipment’ (NICOLE) was installed at the on-line isotope separator ISOLDE 3 at CERN in 1988. The main purpose of the NICOLE facility is to implant the unique ISOLDE mass separated short-lived radioactive isotopes into a pre-cooled ferromagnetic foil. The implanted nuclei, cooled to milliKelvin (mK) temperatures in a sufficiently strong hyperfine field in the ferromagnetic foil, become polarized and emit radiation with an anisotropic spatial angular distribution with respect to the axis of the applied field. The angular distribution is determined by nuclear parameters such as ground state spin, electromagnetic moments and the multipolarity of emitted radiation, as well as by the solid state properties of the implant in the host lattice, including the hyperfine field, the electric field gradient and the spin-lattice relaxation time.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have