NN2012, May 31 th 2012, San Antonio, TX M. Barbui

J fs CD 4 can be used in place of D 2 3 He can be added in different concentrations 1.Most of the laser energy is absorbed by the molecular clusters 2.The electrons escape first and the clusters coulomb explode 3.Some of the ions have enough energy to drive nuclear reactions Expected fusion reactions: D + D  T (1.01 MeV) + p (3.02 MeV) (50%) D + D  3 He (0.82 MeV) + n (2.45 MeV) (50%) cryogenic D + 3 He  4 He (3.6 MeV) + p (14.69 MeV) (100%) D + T  4 He (3.5 MeV) + n (14.1 MeV) (100%) D + 3 He  4 He (3.6 MeV) + p (14.69 MeV) (100%)

 Use the yield of 14.7 MeV protons from the D- 3 He reaction to extract the astrophysical S factor at very low energies.  Since our medium is highly ionized and the electrons move away much faster than the ions we might be able to have a direct measurement of the bare nucleus S factor.  We used the D-D reaction as reference to extract the density of the medium. This reaction has been extensively studied in the last decades. R-matrix calculations of the cross-section of the 4 He system are very stable and are supposed to be correct within a 5% for energies up to 1 MeV [Nucl. Fusion 32(1992)611]

Phase 1  D 2 clusters  D 2 clusters + 4 He Phase 2  D 2 clusters + 3 He  CD 4 clusters + 3 He D ions Temperature KT Yield of 2.45MeV n from D+D->n+ 3 He Yield of 3.02MeV p from D+D->p+T Relative concentration of D and 4 He Check that adding 4 He does not affect the cluster formation D ions Temperature KT Yield of 2.45MeV n from D+D->n+ 3 He Yield of 14.7MeV p from D+ 3 He->p+ 4 He Relative concentration of D and 3 He The experimental yields of 14.7 MeV protons are normalized to the same atomic density of D and 3 He

Proton A Proton B Neutron 4 Neutron 2 Neutron 3 Neutron 1 Laser beam direction Proton C Faraday cup 3 plastic scintillators from UT Cryo-cooled nozzle 3 plastic scintillators from UT

Temperature and the number of the energetic ions 3 MeV 14.7 MeV Faraday cup 4 liquid scintillators NE213 placed at different angles and 6 plastic scintillators placed at 90 degrees Thin (254 um) plastic scintillators BC400. Yield of 3.02 MeV protons Yield of 14.7 MeV protons Yield of 2.45 MeV neutrons

No evidence of angular distribution for 2.45 MeV n or 3 MeV p Same yield for 2.45MeV n and 3 MeV p A different density of D atoms in different shots produce those different lines. Decreasing density

Detection limit for the Faraday cup Temperature estimated from the ratio The ratio of the two yields is independent of the atomic density and shows a smooth behavior Same density effect noticed for the D-D reaction

D-D reactions may happen inside the plasma plume between two energetic D ions coming from the Maxwellian distribution of measured KT or between an energetic D ion and a D at rest outside the plasma plume.  D-D 2*R=5 mm 2*r= mm

D- 3 He reactions happen between energetic D ions coming from the measured Maxwellian distribution and 3 He atoms at rest.  D- 3 He

 Numerical integral with parameterization S(E) from [1] - NACRE database  Numerical integral with parameterization S(E) from [1] - NACRE database /v [1]Nucl. Fusion 32(1992)611

 Numerical integral with parameterization S(E) from [1] - NACRE database /v  Numerical integral with parameterization S(E) from [1] - NACRE database [1]Nucl. Fusion 32(1992)611

Temperature estimated from the ratio Calculated ratio 1) The yield ratio is independent of the atomic density 2) The temperatures estimated from the yield ratios agree with the temperatures measured from the time of flight 3) Therefore for each point there is an atomic density that reproduces both the yield of 2.45MeV neutrons and 14.7 protons.

The yield of protons is calculated using : Our data can be described by the bare nucleus S(E) parameterization from ref [1]. CD 4 The calculated yield agrees with the measured one within the experimental errors.

Fitting function: The parameters b1,b2,b3 define the resonance at E=210 MeV and are fixed to the values of [1] The parameters a1, a2, a3 are free

Aliotta 01 direct data Krauss 87 direct data  La Cognata 05 THM “bare nucleus” ─ This work ─ La Cognata 05 fit line

 We measured the yield of D(D,T)p, D(D, 3 He)n and D( 3 He,  )p and the ion temperature.  The temperature can also be calculated using the ratio of the yield of D-D and D- 3 He reactions This temperature agrees with the measured one within the experimental errors.  If we use the D-D reaction to estimate the atomic density of D. We can use the experimental values of D-3He to fit the parameterization of S(E) D-3He  Our values are agreement with what used so far.

 Improvements of the measurement Measure of the cluster size and the electron density using Ryleigh scattering and short pulse interferometry as described in [Rev. Sci. Inst. 69(1998)3798] Repetition of many shots without changing the nozzle conditions. Larger dimensions of the detectors used for the 14.7MeV protons in order to decrease the statistical error.  Other reactions of can be studied with the same method

 Texas A&M: M. Barbui, K. Hagel, J.B. Natowitz, K. Schmidt, G. Giuliani.  INFN Italy: A. Bonasera (LNS), S. Kimura (LNS), M. Mazzocco (PD).  University of Texas: W. Bang, G. Dyer, H. Quevedo, E. Gaul, T. Borger, A. Bernstein, M. Martinez, M. Donovan, T. Ditmire.  ENEA Italy: F. Consoli, R. De Angelis, P. Andreoli.