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Underground Astrophysics at Surface Facilities: the Atomki case Zs. Fülöp ATOMKI, Debrecen, Hungary LUNA Collaboration Germany, Hungary, Italy, UK When time, money, manpower matter: A network of satellite overground labs is needed Atomki, Debrecen, Hungary Looking for mountains… Before accelerator: deccelerator • 27Al(α,n)30P • First nuclear reaction in Debrecen • CO2 pressure → α-energy Before accelerator: deccelerator excitation function determined with activation method LUNA history: overground contribution • • • • Same experimental approach at higher energies Different experimental approach at higher energies Feasibility studies (target properties) Auxiliary experiments (half-lives, stopping power) Atomki: 7% of Hungary’s RI --- 20% of physics RI Strategic Research Infrastructures All validated by the NEKIFUT (Hungarian ESFRI) committee Atomki facilities: • Atomki Accelerator Centre • Atomki Environmental Laboratory • Atomki Nuclear and Astrophysics Laboratory New Tandetron Laboratory 17O(p,)18F • Advanced hydrogen burning key reaction • Preliminary results: poster prize at EuNPC, 2015 9 Target preparation and analysis • evaporation, Atomic Layer Deposition • in situ SNMS-XPS-SPM + µIBA Low energy 3He(α,γ)7Be activation Activation vs. in beam approach: – – – – – Partly independent (irradiation + off-line γ) Inherent 4π cross section (no angular effects) Off-line part can be repeated (long half-life) Well-known background (no beam induced bg) No summing problems – Cannot reach “low” energy A good tool to investigate systematic errors !!! Complementary Measurements at ATOMKI Catcher purity investigation overground: possible DH2+ or DD+ parasitic beam along with 6Li or 10B impurity in beam stop: •6Li(p,)7Be: = 7.7nb @ EDH2+=233 keV •6Li(d,n)7Be: = 1.08mb @ EDH2+=233 keV •10B(p,)7Be: = 5.75b @ EDH2+=233 keV beam and beam stop purity is crucial OFHC catcher purity • Irradiations by 700 keV p and d at ATOMKI • Analysis of residual activity • 6Li(d,n)7Be cross section → subPPM 6Li concentration 7Be custom reference source production • Irradiation of LiF targets at ATOMKI • 7Li(p,n)7Be, Ep=2.5 MeV • Thin backings • Protective layer • 50 cps gamma Reference activity: • ISO 9001 ATOMKI • LNGS Production of 7Be at Atomki via the 7Li(p,n)7Be nuclear reaction Proton beam Ep = 10.5 MeV; Ip = 18 A magnetically deflected and rotated Irradiation time: tirr = 105 h Li-target Produced activity: A = 7x109 Bq Thickness: d = 2.5 mm Vacuum window foil 21 µm DURATHERM Copper backing He-gas in He-gas out Water in Water out Target cooling: Bombarded surface: He-gas jet (pHe=1.6 bar; T 300 K) Back side of the Cu backing: Water stream Recent upgrades at the vertical isotope production beam line New hardware for the control and for the vacuum systems New control software New target cooling systems and pneumatics New target unit for 7Be production New electronics for beam rotating LUNA members from Atomki • • • • • Z. Elekes Zs. Fülöp Gy. Gyürky E. Somorjai (prof. emeritus) T. Szücs