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Search for low spin states at high excitation energies in 20 Ne with the p,t reaction iThemba LABS &...
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Transcript of Search for low spin states at high excitation energies in 20 Ne with the p,t reaction iThemba LABS &...
![Page 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.](https://reader033.fdocuments.net/reader033/viewer/2022042707/5a4d1b687f8b9ab0599b20c2/html5/thumbnails/1.jpg)
Search for low spin states at high excitation energies in 20Ne
with the p,t reactioniThemba LABS & Stellenbosch University
Energy Postgraduate Conference 2013
![Page 2: Search for low spin states at high excitation energies in 20 Ne with the p,t reaction iThemba LABS & Stellenbosch University Energy Postgraduate Conference.](https://reader033.fdocuments.net/reader033/viewer/2022042707/5a4d1b687f8b9ab0599b20c2/html5/thumbnails/2.jpg)
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. 8Be, 12C • Want to find 5 alpha cluster state in 20Ne
• To use 22Ne(p,t)20Ne reaction with K600 magnetic spectrometer
![Page 3: Search for low spin states at high excitation energies in 20 Ne with the p,t reaction iThemba LABS & Stellenbosch University Energy Postgraduate Conference.](https://reader033.fdocuments.net/reader033/viewer/2022042707/5a4d1b687f8b9ab0599b20c2/html5/thumbnails/3.jpg)
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
![Page 4: Search for low spin states at high excitation energies in 20 Ne with the p,t reaction iThemba LABS & Stellenbosch University Energy Postgraduate Conference.](https://reader033.fdocuments.net/reader033/viewer/2022042707/5a4d1b687f8b9ab0599b20c2/html5/thumbnails/4.jpg)
Experimental tool: The K600 spectrometerK600 contains:1 Quadrupole, 2 dipoles, H- and K-coil (focussing magnets)Best (p,p') resolution: 25 keVBest (α,α') resolution: ~50 keV (for 200 MeV beams)
![Page 5: Search for low spin states at high excitation energies in 20 Ne with the p,t reaction iThemba LABS & Stellenbosch University Energy Postgraduate Conference.](https://reader033.fdocuments.net/reader033/viewer/2022042707/5a4d1b687f8b9ab0599b20c2/html5/thumbnails/5.jpg)
Experimental tool: The 22Ne gas targetCell enclosed between two 6 micron Aramid windows containing gas• Entrance area: 1⨯3 cm2
• Target 1 cm thick• Gas target was used before with K600 during experiment in 2009...
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Preliminary data22Ne(p,t)20Ne at 0°Red – 33.5 MeV Green – 36 MeV Orange – 41 MeV Blue – 46 MeV Magenta – 52 MeVBlack – Aramid background
Excitation energy [MeV]
Counts/10 keV
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Preliminary data
Excitation energy [MeV]
Counts/10 keV
Candidate isobaric analogue states
22Ne(p,t)20Ne at 0°Blue – 33.5 MeV Red – 36 MeV Black – Aramid background
5-alpha prediction - PRC 69 024309 (2004)
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Preliminary data
Angular distribution of known states
Angular distribution of Isobaric Analogue candidates
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Interpretation of the new states
Prediction from Werner Richter's IMME calculation for strong isobaric analogue candidates:
Calculations for T=2 states20.59 MeV 20Ne - 3.856 MeV 20O 21.168 MeV 20Ne – 4.435 MeV 20O21.796 MeV 20Ne – 5.063 MeV 20O
Known in 20O 3.570 MeV 4+ 20O4.072 MeV 2+ 20O4.456 MeV 0+ 20O 4.850 MeV 4+ 20O5.002 MeV 20O5.234 MeV 2+ 20O
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Interpretation of the new statesPrediction by Alex Brown using NuShellX and Fresco:
Experimental cross sections from present measurement at θLAB=0∘: