J. W. Lightbody

Electron scattering studies of low-lying collective states of even Zn isotopes

Abstract The inelastic electron scattering cross sections for the excitation of the low-lying collective states in the even Zn isotopes 64 Zn, 66 Zn, 68 Zn and 70 Zn have been measured in the momentum transfer region q = 0.3–1.1 fm −1 . Strong transitions to the first 2 + and 3 − states have been observed and the modified Tassie model with a two parameter Fermi charge distribution for the ground state was used to extract the values for the reduced transition probability B ↑ (E λ ). Besides the investigation of these states, which in the framework of the vibrational model are considered as one-phonon states, special effort was made to measure the transition to the 2 + two-phonon states in 64 Zn ( e = 1.80 MeV) and 70 Zn ( e = 1.76 MeV). We have applied the anharmonic vibrator model to these two nuclei and have extracted values for the static quadrupole moment of the first excited state.

The charge distribution of 12C

Abstract We report the results of a precision absolute elastic electron scattering on carbon from which we determine the shape of the ground-state charge distribution and the rms charge radius to an accuracy significantly better than heretofore achieved.

Preliminary results of a new determination of the rms charge radius of the proton

Abstract New absolute and relative cross sections for elastic scattering of electrons from the proton have been measured using the linac facilities at NIST. The data were obtained using a high-pressure, flowing-gas target cell alternately filled with H 2 and CH 4 gas. The measurements span a momentum transfer range from 0.22 to 0.73 fm −1 . These new results have been combined with an extensive set of existing elastic electron scattering data in a Fourier-Bessel analysis to obtain the charge density parameters and the rms radius of the proton. Some selection among the available data was necessary because of inconsistencies between published data sets. We obtain an rms radius of 0.865 ±0.020 fm.

A flowing gas target system for precision electron scattering measurements

Abstract We describe a flowing gas target system which can be used in various electron scattering experiments that require gas density stabilization to one part in 103. The main advantage of this system is that both target pressure and temperature are directly monitored during the data taking process. This eliminates the need to use extra beam time to measure the dependence of local target density on beam current. The system has been successfully used in an elastic electron scattering experiment to obtain a precise measurement of the nuclear ground state rms charge radius 4He.

Search for the lowestT = 2 state in14C by inelastic electron scattering

SummaryA search for the lowest-energyT = 2 state in14C has been attempted employing inelastic electron scattering techniques. Spectra obtained at 61 and 81 MeV incident-electron energy and 145.7° scattering angle fail to reveal significant structure at the predicted resonance energy. The implications of this result are discussed in terms of the particle-hole model and the ground-state structure of the14B analogue of this level.RiassuntoSi è cercato di condurre una ricerca dello stato di energia minimaT = 2 nel14C servendosi delle tecniche di scattering anelastico degli elettroni. Negli spettri ottenuti per valori dell’energia degli elettroni incidenti di 61 e 81 MeV e dell’angolo di scattering di 145.7°, non si riescono a scorgere strutture significative ai previsti valori dell’energia di risonanza. Si discutono le implicazioni di questo risultato alla luce del modello a particelle e lacune e della struttura dello stato fondamentale dell’analogo di questo livello nel14B.РеэюмеИспольэуя технику неупругого рассеяния злектронов, исследуется состояниеT = 2 с наименьщей знергией в14C. Полученные спектры при знергии падаюших злектронов 61 и 81 МзВ при угле рассеяния 145.7° не обнаруживают сушественной структуры при предскаэанной реэонансной знергии. Полученный реэультат обсуждается с помошью модели ? частица-дырка ? и структуры основного состояния для14B аналога зтого уровня.

Search for the lowest T = 2 state in 14 C by inelastic electron scattering

SummaryA search for the lowest-energyT = 2 state in14C has been attempted employing inelastic electron scattering techniques. Spectra obtained at 61 and 81 MeV incident-electron energy and 145.7° scattering angle fail to reveal significant structure at the predicted resonance energy. The implications of this result are discussed in terms of the particle-hole model and the ground-state structure of the14B analogue of this level.RiassuntoSi è cercato di condurre una ricerca dello stato di energia minimaT = 2 nel14C servendosi delle tecniche di scattering anelastico degli elettroni. Negli spettri ottenuti per valori dell’energia degli elettroni incidenti di 61 e 81 MeV e dell’angolo di scattering di 145.7°, non si riescono a scorgere strutture significative ai previsti valori dell’energia di risonanza. Si discutono le implicazioni di questo risultato alla luce del modello a particelle e lacune e della struttura dello stato fondamentale dell’analogo di questo livello nel14B.РеэюмеИспольэуя технику неупругого рассеяния злектронов, исследуется состояниеT = 2 с наименьщей знергией в14C. Полученные спектры при знергии падаюших злектронов 61 и 81 МзВ при угле рассеяния 145.7° не обнаруживают сушественной структуры при предскаэанной реэонансной знергии. Полученный реэультат обсуждается с помошью модели ? частица-дырка ? и структуры основного состояния для14B аналога зтого уровня.

Search for the lowestT = 2 state in14C by inelastic electron scattering@@@Исследование ниэщего состоянияT=2 в14C с помошью неупругого рассеяния злектронов

SummaryA search for the lowest-energyT = 2 state in14C has been attempted employing inelastic electron scattering techniques. Spectra obtained at 61 and 81 MeV incident-electron energy and 145.7° scattering angle fail to reveal significant structure at the predicted resonance energy. The implications of this result are discussed in terms of the particle-hole model and the ground-state structure of the14B analogue of this level.RiassuntoSi è cercato di condurre una ricerca dello stato di energia minimaT = 2 nel14C servendosi delle tecniche di scattering anelastico degli elettroni. Negli spettri ottenuti per valori dell’energia degli elettroni incidenti di 61 e 81 MeV e dell’angolo di scattering di 145.7°, non si riescono a scorgere strutture significative ai previsti valori dell’energia di risonanza. Si discutono le implicazioni di questo risultato alla luce del modello a particelle e lacune e della struttura dello stato fondamentale dell’analogo di questo livello nel14B.РеэюмеИспольэуя технику неупругого рассеяния злектронов, исследуется состояниеT = 2 с наименьщей знергией в14C. Полученные спектры при знергии падаюших злектронов 61 и 81 МзВ при угле рассеяния 145.7° не обнаруживают сушественной структуры при предскаэанной реэонансной знергии. Полученный реэультат обсуждается с помошью модели ? частица-дырка ? и структуры основного состояния для14B аналога зтого уровня.