B. Girolami

Project GRAAL: the scientific case

SummaryBackward Compton scattering of laser light against the high-energy electrons circulating in storage rings has produced tagged beams of fully polarized high-energy gamma-rays with an intensity useful for the study of photoreactions. At the ESRF this technique will produce a beam of 1.5 GeV and an intensity of 107 photons per second. We discuss the technical characteristics of such a project and the scientific goals which can be achieved in the study of the electromagnetic transitions of the hardrons and the photoproduction of isobars and strange particles in nucleons and nuclei.

Physics with polarized photons

The role that polarization can play in the interaction of real and virtual photons with nuclear matter is considered. Linear, circular, and elliptical polarization are considered. Photodisintegration of the deuteron with linearly polarized photons is then examined, followed by use of circularly polarized photons with a polarized target. 30 refs., 4 figs. (LEW)

Deuteron photodisintegration induced by monochromatic, linearly polarized gamma‐rays

Measurement of the asymmetry factor in D(γ,u2009np) is reported and the result is discussed in the framework of Partovi’s theory.

Photofission cross-section of238U in the quasi-deuteron region@@@Поперечное сечение фотоделения138U в квази-дейтонной области

SummaryThe photofission cross-section of238U induced by monochromatic and polarized photons has been measured using the LADON facility at the Frascati National Laboratory. The experiment has been performed at six different energies in the range (46÷72) MeV by detecting the fission fragments either in uranium-loaded nuclear-track emulsion plates or in uranium-mica sandwiches. Results are consistent with existing data, however they suggest the opportunity of further investigation in this energy range.RiassuntoLa sezione durto di fotofissione dell238U indotta da fotoni monocromatici e polarizzati è stata misurata usando il fascio LADON dei Laboratori Nazionali di Frascati. Lesperimento è stato realizzato a sei differenti energie nellintervallo (46÷72) MeV rivelando i frammenti di fissione o in emulsioni nucleari arricchite con uranio o in pacchetti di fogli di uranio e mica. I risultati sono consistenti con i dati disponibili, ma suggeriscono comunque lopportunità di un ulteriore studio in questo intervallo energetico.РезюмеИспользуя пучок LADON в национальной лоборатории фраскати, измеряется поперечное сечение фотоделения238U, индуцированного монохроматическими и поляризованными фотонами. Эксперимент проведен при шести различных энергиях в области (46÷72) МэВ, причем фрагменты деления детектируются либо ядерными эмульсиями, обогащенными ураном, либо в сандвичах слоев урана и слюды. Полученные результаты согласуются с существующими данными. Кроме того, эти результаты представляют благоприятную возможность дополинтельного исследования в этой области энергий.