arXiv subjects

R. Hertenberger

Publications and source records attributed to R. Hertenberger.

46 records · Page 3Linked to original sources

arXiv2009

Spectroscopy of 230Th in the (p,t) reaction

The excitation spectra in the deformed nucleus 230Th were studied by means of the (p,t) reaction, using the Q3D spectrograph facility at the Munich Tandem accelerator. The angular distributions of tritons are measured for about 200 excitations seen in the triton spectra up to 3.3 MeV. Firm 0+ assignments are made for 16 excited states by comparison of experimental angular distributions with the calculated ones using the CHUCK code. Additional assignments are possible: relatively firm for 4 states and tentative also for 4 states. Assignments up to spin $6^+$ are made for other states. Sequences of the states are selected which can be treated as rotational bands and as multiplets of excitations. Experimental data are compared with interacting boson model IBM) and quasiparticle-phonon model (QPM) calculations.

nucl-ex↗

arXiv2009

Role of cross-shell excitations in the reaction 54Fe(d_pol,p)55Fe

The reaction 54Fe(d_pol,p)55Fe was studied at the Munich Q3D spectrograph with a 14 MeV polarized deuteron beam. Excitation energies, angular distributions and analyzing powers were measured for 39 states up to 4.5 MeV excitation energy. Spin and parity assignments were made and spectroscopic factors deduced by comparison to DWBA calculations. The results were compared to predictions by large scale shell model calculations in the full pf-shell and it was found that reasonable agreement for energies and spectroscopic factors below 2.5 MeV could only be obtained if up to 6 particles were allowed to be excited from the f_7/2 orbital into p_3/2, f_5/2, and p_1/2 orbitals across the N=28 gap. For levels above 2.5 MeV the experimental strength distribution was found to be significantly more fragmented than predicted by the shell model calculations.

nucl-ex↗

arXiv2008

Q-Value for the Fermi Beta-Decay of 46V

By comparing the Q-values for the 46Ti(3He,t)46V and 47Ti(3He,t)47}V reactions to the isobaric analog states the Q-value for the superallowed Fermi-decay of 46V has been determined as Q_{EC}(46V)=(7052.11+/-0.27) keV. The result is compatible with the values from two recent direct mass measurements but is at variance with the previously most precise reaction Q-value. As additional input quantity we have determined the neutron separation energy S_n(47Ti)=(8880.51+/-0.25) keV.

nucl-ex↗

arXiv2008

New supersymmetric quartet of nuclei: 192Os, 193Os, 193Ir, 194Ir

We present evidence of the existence of a new supersymmetric quartet of nuclei in the A=190 mass region. The analysis is based on new experimental information on the odd-odd nucleus 194Ir from transfer and capture reactions. The new data allow the identification of a new supersymmetric quartet, consisting of the 192,193Os and 193,194Ir nuclei. We make explicit predictions fo r193Os, and suggest that its spectroscopic properties be measured in dedicated experiments. Finally, we study correlations between different transfer reactions.

nucl-th↗

arXiv2008

Shape coexistence near the neutron number N=20: First identification of the E0 decay from the deformed 0^+_2 state in 30Mg

The 1789 keV level in 30Mg was identified as the first excited 0^+ state by measuring its E0 transition to the ground state. The measured small value of rho^2(E0,0^+_2 --> 0^+_1) = 5.7(14) x 10^-3 implies a very small mixing of competing configurations with largely different intrinsic quadrupole deformation near N=20. Axially symmetric Beyond-Mean-Field configuration mixing calculations identify the ground state of 30Mg to be based on neutron configurations below the N=20 shell closure, while the excited 0^+ state mainly consists of a two neutrons excitated into the nu1 f_{7/2} orbital. Using a two-level model, a mixing amplitude of 0.08(4) can be derived.

nucl-ex↗

arXiv2006

On the mixing strength in the two lowest 0- states in 208Pb

With a resolution of 3 keV, the two lowest 0- states in 208Pb are identified by measurements of the reaction 207Pb(d, p) with the Muenchen Q3D magnetic spectrograph in a region where the average level spacing is 6 keV. Precise relative spectroscopic factors are determined. Matrix elements of the residual interaction among one-particle one-hole configurations in a two-level scheme are derived for the two lowest 0- states in 208Pb. The off-diagonal mixing strength is determined as 105 +-10(experimental) +-40(systematic) keV. Measurements of the reaction 208Pb(p,p') via isobaric analog resonances in 209Bi support the structure information obtained.

nucl-ex↗

arXiv2006

An experiment for the measurement of the bound-beta decay of the free neutron

The hyperfine-state population of hydrogen after the bound-beta decay of the neutron directly yields the neutrino left-handedness or a possible right-handed admixture and possible small scalar and tensor contributions to the weak force. Using the through-going beam tube of a high-flux reactor, a background free hydrogen rate of ca. 3 s$^{-1}$ can be obtained. The detection of the neutral hydrogen atoms and the analysis of the hyperfine states is accomplished by Lamb shift source type quenching and subsequent ionization. The constraints on the neutrino helicity and the scalar and tensor coupling constants of weak interaction can be improved by a factor of ten.

hep-ex↗

arXiv2006

The i11/2 f5/2 and i11/2 p3/2 neutron particle-hole multiplets in 208Pb

Inelastic proton scattering via isobaric analog resonances allows to derive rather complete information about neutron particle-hole states. We applied this method to the doubly-magic nucleus 208Pb by measuring angular distributions of 208Pb(p, p') on top of the isobaric analog resonances in 209Bi with the Q3D magnetic spectrograph at München. We identify the six states of the i11/2 f5/2 multiplet and the four states of the i11/2 p3/2 multiplet in the energy range 4.6 MeV < Ex < 5.3 MeV. Firm spin assignments for the ten states are given, some of them new. Additional measurements of the reaction 207Pb(d, p) confirm the fragmented i11/2 p1/2 multiplet.

nucl-ex↗

arXiv2005

3D-Hydrogen Analysis of Ferromagnetic Microstructures in Proton Irradiated Graphite

Recently, magnetic order in highly oriented pyrolytic graphite (HOPG) induced by proton broad- and microbeam irradiation was discovered. Theoretical models propose that hydrogen could play a major role in the magnetism mechanism. We analysed the hydrogen distribution of pristine as well as irradiated HOPG samples, which were implanted to micrometer-sized spots as well as extended areas with various doses of 2.25 MeV protons at the Leipzig microprobe LIPSION. For this we used the sensitive 3D hydrogen microscopy system at the Munich microprobe SNAKE. The background hydrogen level in pristine HOPG is determined to be less than 0.3 at-ppm. About 4.8e15 H-atoms/cm^2 are observed in the near-surface region (4 um depth resolution). The depth profiles of the implants show hydrogen located within a confined peak at the end of range, in agreement with SRIM Monte Carlo simulations, and no evidence of diffusion broadening along the c-axis. At sample with microspots, up to 40 at-% of the implanted hydrogen is not detected, providing support for lateral hydrogen diffusion.

cond-mat.mtrl-sci↗

arXiv2003

A Cosmic Ray Measurement Facility for ATLAS Muon Chambers

Monitored Drift Tube (MDT) chambers will constitute the large majority of precision detectors in the Muon Spectrometer of the ATLAS experiment at the Large Hadron Collider at CERN. For commissioning and calibration of MDT chambers, a Cosmic Ray Measurement Facility is in operation at Munich University. The objectives of this facility are to test the chambers and on-chamber electronics, to map the positions of the anode wires within the chambers with the precision needed for standalone muon momentum measurement in ATLAS, and to gain experience in the operation of the chambers and on-line calibration procedures. Until the start of muon chamber installation in ATLAS, 88 chambers built at the Max Planck Institute for Physics in Munich have to be commissioned and calibrated. With a data taking period of one day individual wire positions can be measured with an accuracy of 8.3 micrometers in the chamber plane and 27 micrometers in the direction perpendicular to that plane.

physics.ins-det↗