Ausbeuteverhältnisse einiger durch Kernphotoreaktionen in Cer und Silber erzeugter Aktivitäten

Samples of metallic silver and cerium-oxide have been irradiated with 31 MeV and 34 MeV bremsstrahlung. Relative yields of the induced activities have been obtained by counting the emitted gamma-quanta or byβ-counting. The yield ratio Y [Ag¹⁰⁷ (γ, n) Ag^106m ]/Y [Ag¹⁰⁷ (γ, n) Ag^106g ] for 34 MeV bremsstrahlung was found to be (0.08±0.02). The corresponding ratio Y [Ce¹⁴⁰ (γ, n) Ce^139m ]/Y [Ce¹⁴⁰ (γ, n) Ce^139g ] at 31 MeV was (0.19±0.01).     

Erzeugung 21 neuer kurzlebiger Isomere durch Kernphotoreaktionen

Irradiation of 28 selected elements with 22.5 MeV bremsstrahlung led to the production of numerous short-lived isomeric states by photonuclear reactions. At least 21 of the observed isomeric transitions seem not to have been reported in the literature thus far. The energies and half-lives of the observed transitions were measured using a conventional scintillation spectrometer. The half-lives of the newly discovered isomeric states are in the region between 5·10^?6 and 6·10^?2 seconds. Isotopic assignments and multipolarities of the observed transitions have not yet been established.     

Erzeugung neuer isomerer Kernzustände durch Kernphotoreaktionen am Antimon und Thallium

The systematic search for new short-lived isomeric states has been continued by irradiation of an additional 32 selected elements with 26 MeV bremsstrahlung. Isomeric transitions were detected using a conventional scintillation spectrometer. Irradiation of antimony led to the production of a new (530±50) μsec isomeric state which decays through emission of partially converted (62±2) keV and (76±3) keV gamma rays. The 530 μsec half-life is tentatively associated with the 136 keV level in Sb¹²². An apparent inconsistency in the previously proposed level scheme of Sb¹²² can be removed if the 3.5 min Sb¹²²-activity is assigned to an isomeric level in Sb¹²² lying less than 15 keV above the 136 keV isomeric state. A new measurement of the half-life of this level yielded a value of (4.1₅±0.2) min. Another new isomeric state with a (2.l±0.2) msec half-life was produced by irradiating thallium. The isomeric state decays by emission of two gamma rays of (335±8) keV and (597±12) keV which were found to be in coincidence. Irradiation of erbium led to the production of a short-lived isomeric transition which may be identical with a previously reported Ho-isomer. Results are discussed in the appendix.     

Nuclear structure functions in carbon nearx=1

Data from deep inelastic scattering of 200 GeV muons on a carbon target with squared four-momentum transfer 52 GeV²Q ²200 GeV² were analysed in the region of the Bjorken variable close tox=1, which is the kinematic limit for scattering on a free nucleon. At this value ofx, the carbon structure function is found to beF ₂ ^C 1.2·10^–4. Thex dependence of the structure function forx>0.8 is well described by an exponentialF ₂ ^C exp(–sx) withs=16.5±0.6.Deceased     

Photoprotonen aus Kohlenstoff,Stickstoff, Sauerstoff und Neon

The energy spectra of photoprotons from carbon, nitrogen, oxygen and neon were investigated with 30·5 MeV bremsstrahlung of the Heidelberg betatron using a CsI(Tl)-spectrometer. The known resonances could be confirmed, new resonances are found in nitrogen. Yields and cross sections relative to those of the reaction C¹²(γ, n)C¹¹ are given.