Physics at the Dripline and the LISA spectrometer
Probing the limit of nuclear existence for heavy proton rich nuclei.
The NPG and the Universities of Liverpool and Surrey were awarded an EPSRC grant in 2006 entitled "Probing the limit of nuclear existence for heavy proton rich nuclei”.
The goal of the project is to perform a series of experimental and theoretical studies in extremely proton rich nuclei close to and beyond the proton drip line. This line is defined by nuclei with such a large excess of protons compared with stable isobars that no more protons can be bound to them and they can decay towards stability by proton emission. Investigations in this work will focus on nuclei close to the proton drip line, approaching the intersection of the N=82 and Z=82 shell closures (see Fig. 1).By exploring nuclei at this distant shore of the nuclear landscape, the deviations from the behaviour expected from predictions of nuclear models designed for and fitted to the properties of more stable nuclei should be at their greatest and therefore revealed most clearly.
Many of the nuclei shown in Fig. 1 lie at or beyond the proton drip line and are ideally suited for probing these effects experimentally by virtue of their a, proton or isomer decay properties. Indeed, this is the heaviest region in which in-beam spectroscopic measurements have been performed on nuclei beyond the proton drip line. We will exploit the powerful and highly selective techniques of recoil decay tagging, isomer decay tagging and decay spectroscopy to achieve our goals.
In addition, we will build a new detection system of silicon detectors called LISA (Light Ion Spectrometer Array), which will be used to detect prompt charged particles, such as protons and alpha particles. LISA will facilitate the discovery of new ephemeral proton emitting isotopes and will also be used as a channel selection device in other parts of the programme to provide a quantum leap in sensitivity. LISA will augment the arsenal of spectrometers at Jyväskylä (GREAT+RITU+JUROGAM+SaGe) to provide a unique facility for the spectroscopy of heavy nuclei.
LISA will be a compact silicon detector array around the target as shown in Fig 2.
| LISA @ Liverpool | |||
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| Photos | Photos - JYFL, 22 June 2009 | Videos | CAD gallerie |
| Commissioning - JYFL, 11 Nov 2009 | Simulations | ||
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