Underground Astrophysics at Surface Facilities the Atomki case

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 • 27 Al(α, n)30 P • First nuclear reaction in Debrecen • CO 2 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

17 O(p, )18 F • Advanced hydrogen burning key reaction • Preliminary results: poster prize at Eu. NPC, 2015 9

Target preparation and analysis • evaporation, Atomic Layer Deposition • in situ SNMS-XPS-SPM + µIBA

Low energy 3 He(α, γ)7 Be 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 DH 2+ or DD+ parasitic beam along with 6 Li or 10 B impurity in beam stop: = 7. 7 nb @ EDH 2+=233 ke. V • 6 Li(d, n)7 Be: = 1. 08 mb @ E DH 2+=233 ke. V • 10 B(p, )7 Be: = 5. 75 b @ E DH 2+=233 ke. V • 6 Li(p, )7 Be: beam and beam stop purity is crucial

OFHC catcher purity • Irradiations by 700 ke. V p and d at ATOMKI • Analysis of residual activity • 6 Li(d, n)7 Be cross section → sub. PPM 6 Li concentration

7 Be custom reference source production • Irradiation of Li. F targets at ATOMKI • 7 Li(p, n)7 Be, E =2. 5 Me. V p • Thin backings • Protective layer • 50 cps gamma Reference activity: • ISO 9001 ATOMKI • LNGS

Production of 7 Be at Atomki via the 7 Li(p, n)7 Be nuclear reaction Proton beam Ep = 10. 5 Me. V; Ip = 18 A magnetically deflected and rotated Irradiation time: tirr = 105 h Li-target Produced activity: A = 7 x 109 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 (p. He=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 7 Be production New electronics for beam rotating

LUNA members from Atomki • • • Z. Elekes Zs. Fülöp Gy. Gyürky E. Somorjai (prof. emeritus) T. Szücs