1. Search for low spin states at high excitation energies in 20 Ne with the p,t reaction iThemba LABS & Stellenbosch University Energy Postgraduate Conference 2013

2. Alpha clustering in n-alpha nuclei Threshold rule: n-alpha cluster state expected above n-alpha breakup threshold in all n- alpha nuclei e.g. 8 Be, 12 C Want to find 5 alpha cluster state in 20 Ne To use 22 Ne(p,t) 20 Ne reaction with K600 magnetic spectrometer

3. For 4 weekends from April to July 2012: Proton beam delivered from SPC1 through K line to SSC Accelerated to 60 MeV by SSC Steered through X, P1, P2 and S lines to K600 vault The iThemba LABS cyclotron

4. Experimental tool: The K600 spectrometer K600 contains: 1 Quadrupole, 2 dipoles, H- and K-coil (focussing magnets) Best (p,p') resolution: 25 keV Best ( α, α ') resolution: ~50 keV (for 200 MeV beams)

5. Experimental tool: The 22 Ne gas target Cell enclosed between two 6 micron Aramid windows containing gas Entrance area: 13 cm 2 Target 1 cm thick Gas target was used before with K600 during experiment in 2009...

6. Preliminary data 22 Ne(p,t) 20 Ne at 0 ° Red – 33.5 MeV Green – 36 MeV Orange – 41 MeV Blue – 46 MeV Magenta – 52 MeV Black – Aramid background Excitation energy [MeV] Counts/ 10 keV

7. Preliminary data Excitation energy [MeV] Counts/ 10 keV Candidate isobaric analogue states 22 Ne(p,t) 20 Ne at 0 ° Blue – 33.5 MeV Red – 36 MeV Black – Aramid background 5-alpha prediction - PRC 69 024309 (2004)

8. Preliminary data Angular distribution of known states Angular distribution of Isobaric Analogue candidates

9. Interpretation of the new states Prediction from Werner Richter's IMME calculation for strong isobaric analogue candidates: Calculations for T=2 states 20.59 MeV 20 Ne - 3.856 MeV 20 O 21.168 MeV 20 Ne – 4.435 MeV 20 O 21.796 MeV 20 Ne – 5.063 MeV 20 O Known in 20 O 3.570 MeV 4 + 20 O 4.072 MeV 2 + 20 O 4.456 MeV 0 + 20 O 4.850 MeV 4 + 20 O 5.002 MeV 20 O 5.234 MeV 2 + 20 O

10. Interpretation of the new states Prediction by Alex Brown using NuShellX and Fresco: Experimental cross sections from present measurement at θ LAB =0 ∘ :