22 May 2007 Cosener's House 1 Alex Murphy Nuclear astrophysics Dark Matter The Future of Nuclear Astrophysics in the UK

22 May 2007 Cosener's House 2 Outline Who we are What we do The Future: Three examples Other projects/programmes Summary

22 May 2007 Cosener's House 3 Who we are… In virtually every nuclear physics proposal, at some point there are the words …is of Astrophysical relevance… Significant contributions from many nuclear physicists It is highly multidisciplinary and interdisciplinary Specialist groups in the UK are: Edinburgh & York ~6 Academic Staff, +RA.s, +Students

22 May 2007 Cosener's House 4 What we do… Aims of Nuclear Astrophysics An understanding of the origin & evolution of the elements An understanding of the mechanisms driving astrophysical phenomena Timeliness Remarkable observations from new telescopes. New experimental facilities and techniques Our role is to provide the key nuclear inputs that are needed

22 May 2007 Cosener's House 5 abundance Mass number Fe The 11 Greatest Unanswered Questions of Physics National Academy of Science Report, Committee for the Physics of the Universe, 2002 How were the elements from iron to uranium made? These are important questions! Abundance curve of the elements

22 May 2007 Cosener's House 6 Our Science Objectives: How were the elements from iron to uranium made? What leads to the abundances observed in novae? What governs other explosive phenomena? What is the role of nuclear physics in stellar evolution? Crab Nebula SN 1054 Artists conception Chandra observation

22 May 2007 Cosener's House 7 World Context: Europe: FAIR, REX-ISOLDE upgrade, SPIRAL-II, Eurisol US: Facility for Rare Isotope Beams Canada: ISAC-II Japan: BigRIPS China: HIRFL (Lanzhou) … The desire to understand astrophysical phenomena is a major motivation for significant investment in new facilities around the world. The UK has a strong track record and is well placed to play a major role in these activities

22 May 2007 Cosener's House 8 The Future: Three examples… AIDA TACTIC

22 May 2007 Cosener's House 9 Advanced Implantation Detector Array (AIDA) Scientific Motivation: The r-process Collaboration: The University of Edinburgh (lead) The University of Liverpool CCLRC DL & RAL Project Manager: Tom Davinson Further information: Technical Specification:

22 May 2007 Cosener's House 10 AIDA: Science Case [Fe/H] < -3.0 Unique r-process What is its site? How does it operate? Recent Observations of Metal Poor Stars

22 May 2007 Cosener's House Cd R – abundances Details of nuclear properties R-process studies Z N neutrons protons Key sources of uncertainty are the properties of highly neutron rich nuclei

22 May 2007 Cosener's House 12 GSI today Future facility FAIR

22 May 2007 Cosener's House 13 AIDA Concept R-process nuclei implanted into multi-plane, highly segmented DSSD array Observe subsequent decays: p, 2p, p, n … Measure half lives, branching ratios, decay energies … Tag interesting events for coincident gamma and neutron detector arrays Long half-lives, requiring high segmentation 4096 channels & Application Specific Integrated Circuits Significant advance on present technology

22 May 2007 Cosener's House 14 Scientific Motivation: Direct measurements of low energy nuclear astrophysical reactions using radioactive beams Collaboration: The University of York (lead) TRIUMF, Canada (ACTAR-EURONS) Project leader: Alison Laird Further information: TRIUMF Annular Chamber for Tracking and Identification of Charged particles (TACTIC)

22 May 2007 Cosener's House 15 Why TACTIC? Allows exploration of previously impossible-to-access reactions Gas targets Low energies Tracking Particle ID Direct measurements Large solid angle / High efficiency Radiation Hard Can be complemented with -ray array Optimised for 8 Li(,n) : But much much more too! Opens up many new scientific possibilities Radical, adventurous project for UK nuclear physics

22 May 2007 Cosener's House 16 Schematic design of TACTIC detector GEM readout Design: Completed

22 May 2007 Cosener's House 17 Construction: Almost complete In-beam testing: Aug 2007 TACTIC: Status

22 May 2007 Cosener's House 18 Experimental Low Energy Nuclear Astrophysics ( ELENA) Scientific Motivation: Direct measurements nuclear astrophysical reactions at the Gamow energy Proposer: The University of Edinburgh Marialuisa Aliotta Technical Specification: Contact: Marialuisa Aliotta

22 May 2007 Cosener's House 19 ELENA Motivation Cosmic ray induced backgrounds hamper rare event searches Key astrophysical important reactions would be much better studied in a cosmic ray free environment There exists an underground science laboratory in the UK at Boulby Proposal An underground low energy accelerator for nuclear astrophysics

22 May 2007 Cosener's House 20 a working potash and salt mine Cleveland - North East England the deepest mine in Britain (850m to 1.3km deep) Middlesborough Whitby Staithes York Sylvanite courtesy: S. Paling Boulby Mine

22 May 2007 Cosener's House 21 Map of excavations Mine Shafts Dark Matter Research Areas Underground science established 1km

22 May 2007 Cosener's House 22 Requirements for an underground lab... Low Backgrounds Deep (to shield from cosmic rays) Low background rock/lab (and/or adequate shielding) Plenty of Laboratory space Easy access for equipment Good infrastructure + facilities 2805 mwe attenuates CR by ~10 6 Salt is low in Uranium & Thorium Virtually unlimited potential for expansion Via mine shaft (4m lengths) + Transport underground JIF laboratory, CPL Support Why is Boulby Special?

22 May 2007 Cosener's House 23 Advantage of salt mine: extremely low background at E < 2-3 MeV Why is Boulby Special? Gran Sasso Boulby

22 May 2007 Cosener's House 24 What will be involved? 3 MV single-ended machine (e.g. NEC, Pelletron) ECR source (e.g. for high intensity (~500 A) 12 C beam at high charge states) Beam-lines + detection systems (gamma, neutron, charged particles) Ion (charge state)Particles per second H+H+ 5.0x10 14 He + 5.0x10 13 He x10 13 Xe x10 12 Kr x10 11 Ar x10 11 Ne x10 12 Fe x10 11 (estimated) Ni x10 11 (estimated)

22 May 2007 Cosener's House 25 Is there a role for ELENA? Only other comparison is LUNA at the Gran Sasso … a 400 kV machine Limited to acceleration of H and He beams Only direct kinematics studies are possible beam-induced background on target impurities a problem Reactions producing neutrons are not allowed Space limited Key studies: Carbon burning in advanced stages of stellar evolution Neutron sources for s-process Ne, Na, Mg and Al nucleosynthesis in AGB stars

22 May 2007 Cosener's House 26 ELENA Statement of Interest has been submitted to STFC Background level ~ factor lower than at GS No space constraints (no interference with other experiments) Existing support and safety facilities Opportunities for involvement at various level Workshop planned in Edinburgh July 2007

22 May 2007 Cosener's House 27 Not enough time to mention…

22 May 2007 Cosener's House 28 TIGRESS-SHARC York contribution to TIGRESS Light ion transfer reactions E.g. 59,60 Fe(d,p) to determine supernova (n, ) rates New silicon barrel and Bragg detector

22 May 2007 Cosener's House 29 ERAWAST See next months Nuclear Physics News. Aim is to make use of long lived radionuclides that have built up from irradiation of the PSI beam dumps E.g. 44 Ti (t ½ = 60 yr) 44 Ti(,p), relevant to 44Ti abundance in SNe Rate is needed to allow comparison of -ray observation of 44 Ti with core collapse models Unique diagnostic of the collapse mechanism Exotic Radionuclides from Accelerator Waste for Science and Technology

22 May 2007 Cosener's House 30 Ongoing programmes of research Louvain-la-Neuve Pioneering radioactive nuclear beams. LEDA – Pioneering large segmented Si Measuring nuclear properties relevant to novae & XRBs

22 May 2007 Cosener's House 31 Ongoing programmes of research TRIUMF TUDA

22 May 2007 Cosener's House 32 Other ongoing/planned activities Plus, unique needs of certain experiments require activity at other locations, e.g. ANL REX-ISOLDE GANIL Orsay ORNL ANU …

22 May 2007 Cosener's House 33 Summary Exciting Science New Ideas New Scientific Opportunities Use of Many Experimental Techniques

22 May 2007 Cosener's House 34 Extra slides

22 May 2007 Cosener's House 35

22 May 2007 Cosener's House 36

22 May 2007 Cosener's House 37

22 May 2007 Cosener's House 38

22 May 2007 Cosener's House 39

22 May 2007 Cosener's House 40 25,26 Al(p, ) 26,27 Si reactions influence predicted flux of the cosmic γ-ray emitter 26 Al

22 May 2007 Cosener's House C 13 N 14 N 15 O 14 O 15 N 13 C 16 O 17 O 18 O unstable stable HCNO 23 Mg 21 Mg 22 Mg 25 Al 24 Al 24 Mg 25 Mg 26 Al 26 Mg 27 Al 27 Si 28 Si rp-process onset 17 F 18 F 18 Ne 20 Ne 19 Ne 21 Na 22 Na 20 Na 19 F 21 Ne 22 Ne 23 Na HCNO breakout NeNa cycle (, ) (p, ) ( + ) (p, ) (,p) some key reactions: 14 O(,p) 17 F 18 Ne(,p) 21 Na 21 Na(p, ) 22 Mg 15 O(, ) 19 Ne 19 Ne(p, ) 20 Na 20 Na(p, ) 21 Mg 18 F(p, ) 15 O 26 Al(p, ) 27 Si

22 May 2007 Cosener's House 42 T 1/2 =1.7s 3 flow T~3*10 8 K gm.cm -2 Hot CNO Cycle Key unknown reaction rates are dominated by resonance reactions 17 F(p, Ne, 14 O( p) 17 F, 18 F(p, Experiments require intense radioactive beams ~1 MeV/u

22 May 2007 Cosener's House 43 breakout processing beyond CNO cycle after breakout via: T O(, ) 19 Ne 18 Ne(,p) 21 Na T flow For X-ray bursters a similar scenario prevails although in this case material accretes onto the surface of a neutron star rather than a white dwarf Consequently higher T and can result in breakout from the hot CNO cycles

22 May 2007 Cosener's House C+ 12 C importance: evolution of massive stars Gamow region: 1 – 3 MeV min. measured E: 2.1 MeV (by -ray spectroscopy) passive lead & concrete shielding Major improvements expected for measurements underground! Crab Nebula SN 1054 Aguilera et al. PRC 73 (2006) Spillane et al PRL 98 (2007) channel p channel 12 C( 12 C, ) 20 Ne and 12 C( 12 C,p) 23 Na channels

22 May 2007 Cosener's House C(,n) 16 O Contributions from sub-threshold states? Mainly hampered by cosmic background good case for underground investigation importance: s-process in AGB stars Gamow region: keV min. measured E: 270 keV M. Heil, PhD Thesis - Karlsruhe, 2002

22 May 2007 Cosener's House 46 Similar considerations apply also to 22 Ne(, ) 25 Mg reaction Jaeger PRL 87 (2001) Ne(,n) 25 Mg importance: s-process in AGB stars Gamow region: keV min. measured E: ~550 keV mainly hampered by cosmic background good case for underground investigation reaction rate still uncertain by orders of magnitude uncertain nucleosynthesis predictions Karakas et al ApJ 643 (2006) 471

22 May 2007 Cosener's House 47 Abundances of Ne, Na, Mg, Al, … in AGB stars and nova ejecta affected by many (p, ) and (p, ) reactions Iliadis et al. ApJ S134 (2001) 151; S142 (2002) 105; Izzard et al A&A (2007) submitted !! new measurements underground are very much needed !!

22 May 2007 Cosener's House 48 M.S. Smith and K.E. Rehm, Ann. Rev. Nucl. Part. Sci, 51 (2001) The vast majority of reactions encountered in these processes involve UNSTABLE species The Playground