Strong field physics and QED experiments with ELI-NP 2×10PW laser beams

The ELI-NP facility will focus a 10 PW pulsed laser beam at intensities of ∼10 23 W/cm 2 for the first time, enabling investigation of the new physical phenomena at the interfaces of plasma, nuclear and particle physics. The electric field in the laser focus has a maximum value of ∼10 15 V/m at such laser intensities. In the ELI-NP Experimental Area E6, we propose the study of Radiation Reaction, Strong Field Quantum Electrodynamics (QED) effects and resulting production of Ultra-bright Sources of Gamma-rays which could be used for nuclear activation. Two powerful, synchronized 10 PW laser beams will be focused in the E6 Interaction Chamber on either gas or solid targets. One 10 PW beam is the Pump-beam and the other is the Probe-beam. The focused Pump beam accelerates the electrons to relativistic energies. The accelerated electron bunches interact with the very high electro-magnetic field of the focused Probe beam. The layout of the experimental area E6 will be presented with several options for the experimental configurations

Recurrence of hepatocellular carcinoma

Clinica I Chirurgie, Spitalul “Sf.Spiridon”, Departamentul de Chirurgie, Universitatea de Medicină și Farmacie “Gr.T.Popa”, Iași, România, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Introducere: Rezecția hepatică rămâne “standardul de aur” în tratamentul cancerului hepatocelular (CHC). Alegerea variantei de rezecție hepatică depinde de mai mulți factori: localizarea tumorii, dimensiunile tumorii, starea parenchimului hepatic nontumoral, scorul Child-Pugh. Problema recurenței locoregionale în funcție de tipul de rezecție rămâne controversată. Scopul studiului: Ne-am propus să comparăm rata recurenței loco-regionale a CHC în funcție de tipul de rezecție hepatică (anatomică versus non-anatomică). Material și metode: Am analizat 64 de pacienți cu CHC, care au beneficiat de rezecție hepatică curativă în perioada 2005- 2013. Pacienții au fost împărțiți în două loturi: lotul A – 26 de pacienți la care s-a practicat o rezecție hepatică anatomică și lotul B – 38 de pacienți la care s-a practicat o rezecție hepatică non-anatomică. Rezultate: Pe o perioadă de urmărire postoperatorie cuprinsă între 12 și 60 de luni, rata recurenței CHC în cele două loturi a fost de 32% în grupul A și 31,4% în grupul B (P=0,963). Durata medie de apariție a recurenței a fost de 15,63±7,46 luni (între 5 și 25 luni) în lotul A și 16,91±9,35 luni (între 5 și 33 luni) în lotul B (P=0,753). Concluzii: Tipul de rezecție hepatică (anatomică sau non-anatomică) nu influențează apariția recurenței CHC, dacă se respectă limitele oncologice de rezecție.Introduction: Liver resection remains the gold standard in the treatment of hepatocellular cancer (HCC). Choosing liver resection depends on several factors: tumor location, tumor size, condition nontumoral liver parenchyma, Child-Pugh score. The locoregional recurrence problem depending on the type of resection remains controversial. The purpose of the study: We aimed to compare loco-regional recurrence rate of HCC according to the type of hepatic resection (anatomic versus non-anatomical). Material and methods: We analyzed 64 patients with HCC who received curative liver resection during the period 2005-2013. Patients were divided into two groups: group A – 26 patients who underwent hepatic anatomical resection and group B – 38 patients who underwent non-anatomical hepatic resection. Results: On a postoperative follow-up period between 12 and 60 months, HCC recurrence rate in the two groups was 32% in group A and 31.4% in group B (P=0.963). The average length of developing appellant was 15.63±7.46 months (between 5 and 25 months) in group A and 16.91±9.35 months (between 5 and 33 months) in group B (P=0.753). Conclusions: The type of liver resection (anatomical or non-anatomical) does not influence the occurrence of HCC recurrence, if we respect the oncologic limits resection

Prolate-Spherical Shape Coexistence at N=28 in 44^{44}S

The structure of $^{44}$S has been studied using delayed $\gamma$ and electron spectroscopy at \textsc{ganil}. The decay rates of the 0$^+_2$ isomeric state to the 2$^+_1$ and 0$^+_1$ states have been measured for the first time, leading to a reduced transition probability B(E2~:~2$^{+}_1$$\rightarrow$0$^{+}_2)$= 8.4(26)~e$^2$fm$^4$ and a monopole strength $\rho^2$(E0~:~0$^{+}_2$$\rightarrow$0$^{+}_1)$ =~8.7(7)$\times$10$^{-3}$. Comparisons to shell model calculations point towards prolate-spherical shape coexistence and a phenomenological two level mixing model is used to extract a weak mixing between the two configurations.Comment: 5 pages, 3 figures, accepted for publication in Physical Review Letter

New pathway to bypass the 15O waiting point

We propose the sequential reaction process $^{15}$O($p$,$\gamma)(\beta^{+}$)$^{16}$O as a new pathway to bypass of the $^{15}$O waiting point. This exotic reaction is found to have a surprisingly high cross section, approximately 10$^{10}$ times higher than the $^{15}$O($p$,$\beta^{+}$)$^{16}$O. These cross sections were calculated after precise measurements of energies and widths of the proton-unbound $^{16}$F low lying states, obtained using the H($^{15}$O,p)$^{15}$O reaction. The large $(p,\gamma)(\beta^{+})$ cross section can be understood to arise from the more efficient feeding of the low energy wing of the ground state resonance by the gamma decay. The implications of the new reaction in novae explosions and X-ray bursts are discussed.Comment: submitte

Collapse of the N=28 shell closure in 42^{42}Si

The energies of the excited states in very neutron-rich $^{42}$Si and $^{41,43}$P have been measured using in-beam $\gamma$-ray spectroscopy from the fragmentation of secondary beams of $^{42,44}$S at 39 A.MeV. The low 2$^+$ energy of $^{42}$Si, 770(19) keV, together with the level schemes of $^{41,43}$P provide evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that $^{42}$Si is best described as a well deformed oblate rotor.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. let

Probing Nuclear forces beyond the drip-line using the mirror nuclei 16^{16}N and 16^{16}F

Radioactive beams of $^{14}$O and $^{15}$O were used to populate the resonant states 1/2$^+$, 5/2$^+$ and $0^-,1^-,2^-$ in the unbound $^{15}$F and $^{16}$F nuclei respectively by means of proton elastic scattering reactions in inverse kinematics. Based on their large proton spectroscopic factor values, the resonant states in $^{16}$F can be viewed as a core of $^{14}$O plus a proton in the 2s$_{1/2}$ or 1d$_{5/2}$ shell and a neutron in 1p$_{1/2}$. Experimental energies were used to derive the strength of the 2s$_{1/2}$-1p$_{1/2}$ and 1d$_{5/2}$-1p$_{1/2}$ proton-neutron interactions. It is found that the former changes by 40% compared with the mirror nucleus $^{16}$N, and the second by 10%. This apparent symmetry breaking of the nuclear force between mirror nuclei finds explanation in the role of the large coupling to the continuum for the states built on an $\ell=0$ proton configuration.Comment: 6 pages, 3 figures, 2 tables, accepted for publication as a regular article in Physical Review

Asymptotic normalization coefficient of ^{8}B from breakup reactions and the S_{17} astrophysical factor

We show that asymptotic normalization coefficients (ANC) can be extracted from one nucleon breakup reactions of loosely bound nuclei at 30-300 MeV/u. In particular, the breakup of ^{8}B is described in terms of an extended Glauber model. The 8B ANC extracted for the ground state of this nucleus from breakup data at several energies and on different targets, C^2 = 0.450+/-0.039} fm^-1, leads to the astrophysical factor S_{17}(0)= 17.4+/-1.5 eVb for the key reaction for solar neutrino production 7Be(p,gamma)8B. The procedure described here is more general, providing an indirect method to determine reaction rates of astrophysical interest with beams of loosely bound radioactive nuclei.Comment: 4 pages, RevTex, 3 figures revised version to appear in Phys Rev Let

Structure around the island of inversion with single-neutron knockout reactions at GANIL

The nuclear structure of the 31Mg nucleus has been studied with the singleneutron knockout reaction. We report on the preliminary results of an experiment performed with the EXOGAM array coupled, for the first time, to the SPEG spectrometer at GANIL.We present a provisional result for the inclusive single-neutron knockout cross section of σinc= 90(5) mb. Preliminary exclusive cross sections for the measured bound states, including the ground state, are also presented. Finally, preliminary longitudinal momentum distributions for the ground state and first excited state are also shown. These results are compared to Monte Carlo Shell-Model calculations in the sd-pf region