[Bubble] more competition

[Ugalde, Claudio]

Yes, I believe years ago we put numbers and as usual, the problem is always the 4He targets. Luminosity-wise , implanted targets will blister as low as 20 uA even with the best cooling and He ions will diffuse out fast. Then gas targets: even Jensa, presumably the thickest ever built, is many orders of magnitude thinner than ours. 

Their cosmic background is very promising. Their beam+target backgrounds are just the same. One really needs a recoil separator to improve things. 

However, it is wonderful to hear that their lab became a reality. 

Claudio

> On Oct 22, 2018, at 6:29 AM, Jay Benesch <benesch at jlab.org> wrote:
> 
> https://urldefense.proofpoint.com/v2/url?u=https-3A__arxiv.org_abs_1810.08201&d=DwIGaQ&c=lz9TcOasaINaaC3U7FbMev2lsutwpI4--09aP8Lu18s&r=QIqmw5JVs6zZFqfrz-7aQA&m=EbtCkFicPzmN1dNznknFV39l2PPpbBKkKwPXz-S3l5A&s=R_8UOmlPYt-c6vkKl9-5frBxXiPzGA03rbSlCO9Zv30&e= 
> 
> The new Felsenkeller 5 MV underground accelerator
> Daniel Bemmerer, Thomas E. Cowan, Toralf Döring, Marcel Grieger, Sebastian Hammer, Thomas Hensel, Lisa Hübinger, Arnd R. Junghans, Felix Ludwig, Stefan E. Müller, Stefan Reinicke, Bernd Rimarzig, Konrad Schmidt, Ronald Schwengner, Klaus Stöckel, Tamás Szücs, Steffen Turkat, Andreas Wagner, Louis Wagner, Kai Zuber
> (Submitted on 18 Oct 2018)
> 
>    The field of nuclear astrophysics is devoted to the study of the creation of the chemical elements. By nature, it is deeply intertwined with the physics of the Sun. The nuclear reactions of the proton-proton cycle of hydrogen burning, including the 3He({\alpha},{\gamma})7Be reaction, provide the necessary nuclear energy to prevent the gravitational collapse of the Sun and give rise to the by now well-studied pp, 7Be, and 8B solar neutrinos. The not yet measured flux of 13N, 15O, and 17F neutrinos from the carbon-nitrogen-oxygen cycle is affected in rate by the 14N(p,{\gamma})15O reaction and in emission profile by the 12C(p,{\gamma})13N reaction. The nucleosynthetic output of the subsequent phase in stellar evolution, helium burning, is controlled by the 12C({\alpha},{\gamma})16O reaction.
>    In order to properly interpret the existing and upcoming solar neutrino data, precise nuclear physics information is needed. For nuclear reactions between light, stable nuclei, the best available technique are experiments with small ion accelerators in underground, low-background settings. The pioneering work in this regard has been done by the LUNA collaboration at Gran Sasso/Italy, using a 0.4 MV accelerator.
>    The present contribution reports on a higher-energy, 5.0 MV, underground accelerator in the Felsenkeller underground site in Dresden/Germany. Results from {\gamma}-ray, neutron, and muon background measurements in the Felsenkeller underground site in Dresden, Germany, show that the background conditions are satisfactory for nuclear astrophysics purposes. The accelerator is in the commissioning phase and will provide intense, up to 50{\mu}A, beams of 1H+, 4He+ , and 12C+ ions, enabling research on astrophysically relevant nuclear reactions with unprecedented sensitivity.
> 
> Comments:    Submitted to the Proceedings of the 5th International Solar Neutrino Conference, Dresden/Germany, 11-14 June 2018, to appear on World Scientific
> Subjects:    Accelerator Physics (physics.acc-ph); Nuclear Experiment (nucl-ex); Instrumentation and Detectors (physics.ins-det)
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