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Graphs are given of the maximum proton energies in delayed proton emitters. This quantity, equal to the difference of the electron capture decay energy of the precursor and the separation energy of a proton in the daughter, has been calculated in a least squares adjustment of mass spectroscopic data and nuclear decay and reaction energies. The graphs would lead to expect a 950 keV lower maximum proton energy in73Kr(ɛp)72Se than has been reported from experiments. They can be used to predict new cases for further studies on this subject.

An intranuclear cascade model for reactions of pions and nucleons with complex nuclei that should cover the energy range from about 50 MeV to about 1000 GeV has been developed. The model includes the effect of a diffuse nuclear surface, the Fermi motion of the bound nucleons within the nucleus, the exclusion principle, a local potential for nucleons, a localized reduction in the density of the nucleus during the development of the cascade, and the sequencing of the events correctly with time. Theoretical results from the model are compared with experimental data over the energy range \ensuremath{\sim} 3-1000 GeV. Within the cascade model, the equations that are used to represent the pion multiplicity from the reactions of nucleons and pions with the individual nucleons of the nucleus underestimates the number of shower particles produced by these individual nucleon interactions. In spite of this the predicted number of shower particles escaping from the nucleus, for 100-GeV nuclear interactions, is overestimated by about 25% for light nuclei to about 60% for heavy nuclei. The agreement for the number of escapes from the nucleus is somewhat better at lower interaction energies (\ensuremath{\sim} 10-20 GeV). Some of the major trends in the observed high energy data are predicted quite well. These include the energy independence of (a) the number of black tracks produced at interaction energies above 5 GeV, (b) the number of shower particles produced above 100 GeV, and (c) the radionuclides produced above 10 GeV. Other trends that are predicted fairly well are the small mass dependence of the shower particle multiplicity (factor of 2 increase predicted from carbon to lead; factor of 1.5 measured), and the change in the angular dependence of the multiplicity with mass. In absolute comparisons, the predicted total reaction cross sections are in good agreement with experimental data, and the cross sections for the production of radionuclides are in fair agreement.NUCLEAR REACTIONS Theoretical, intranuclear cascade method, ${\ensuremath{\sigma}}_{t}(A)$ for $p$ and $\ensuremath{\pi}$, ${〈n〉}_{\mathrm{shower}}$ and ${〈n〉}_{\mathrm{black}}$ vs ${E}_{\ensuremath{\pi}}$, $\ensuremath{\sigma}({\ensuremath{\theta}}_{\ensuremath{\pi}})\ensuremath{\Delta}{\ensuremath{\theta}}_{\ensuremath{\pi}}$ vs $A$, $\ensuremath{\sigma}({E}_{\ensuremath{\pi}},{E}_{p}:\ensuremath{\theta})$ for $p$ on Al, radiochemical $\ensuremath{\sigma}'\mathrm{s}$ for 11-and 300-GeV $p$ on $^{59}\mathrm{Co}$. All compared with experiment.

Cross-sections with 14 MeV neutrons for light- and mediumweight nuclei are analysed in terms of the compound nucleus model. The marked regularity in (n, p) cross-sections, pointed out by Gardner and by Levkovskii, can be reproduced fairly well. A systematic trend is found in the variation of Б(n, 2n) with the neutron number of the target nucleus. This is also analysed in terms of the compound nucleus model.

A survey was made of $log\mathrm{ft}$ values for forbidden $\ensuremath{\beta}$ transitions. Three cases, $^{90m}\mathrm{Y}$, $^{65}\mathrm{Ni}$, and $^{144}\mathrm{Pm}$ decays, were examined experimentally. A number of low $log\mathrm{ft}$ values reported in the literature are superseded by more recent larger values. Empirical rules for making spin and parity assignments from $log\mathrm{ft}$ values are proposed.

To him who, in the love of nature, finds occasion to investigate, say, the nuclear properties of europium‐152, nature offers a variety of approaches. The two lowest states have half‐lives of 13 years and 9.3 hours, so their decay properties can be conveniently studied. Further, these states live long enough to be subjected to atomic‐beam, isotope‐shift, isomer‐shift, mass‐spectrometer, and cross‐section experiments, and some such studies have been reported. Higher levels in Eu152 can be studied via neutron capture gamma rays and neutron resonances. They can also be studied through reactions, such as Eu151(d,p), Eu153(d,t), or Sm149(α,p).

The New York Times and Senator Humphrey have been talking about the plight of the poor scientists who find it easier to measure a quantity than to locate the results of earlier experimental work in the library. But instead of making a straightforward attack on the problems of handling the data explosion, everyone seems to be standing by for the day when that popular robot, Mr. Know‐It‐All, will roll himself into the laboratory and speak as follows

An intranuclear cascade model for reactions of pions and nucleons with complex nuclei that should cover the energy range from about 50 MeV to about 1000 GeV was developed. The model includes the effect of a diffuse nuclear surface, the Fermi motion of the bound nucleons within the nucleus, the exclusion principle, a local potential for nucleons, a localized reduction in the density of the nucleus during the development of the cascade, and the sequencing of the events correctly with time. Theoretical results from the model are compared with experimental data over the energy range approximately 3 to 1000 GeV. Within the cascade model, the equations that are used to represent the pion multiplicity from the reactions of nucleons and pions with the individual nucleons of the nucleus underestimates the number of shower particles produced by these individual nucleon interactions. In spite of this the predicted number of shower particles escaping from the nucleus, for 100-GeV nuclear interactions, is overestimated by about 25 percent for light nuclei to about 60 percent for heavy nuclei. The agreement for the number of escapes from the nucleus is somewhat better at lower interaction energies (approximately 10 to 20 GeV). Some of the majormore » trends in the observed high-energy data are predicted quite well. These include the energy independence of the number of black tracks produced at interaction energies above 5 GeV, the number of shower particles produced above 100 GeV, and the radionuclides produced above 10 GeV. Other trends that are predicted fairly well are the small mass dependence of the shower particle multiplicity and the change in the angular dependence of the multiplicity with mass. In absolute comparisons, the predicted total reaction cross sections are in good agreement with experimental data, and the cross sections for the production of radionuclides are in fair agreement. 14 figures, 5 tables.« less

These days ever more data come available on reaction energies connecting pairs of nuclides which are not themselves connected to the system of primaries (nuclides which are connected to each other in many ways). It is the aim of the Atomic Mass Adjustment program1) to compare all available data, to check the system for internal consistency and to produce a list of atomic masses and linear combinations of atomic masses. Therefore unconnected data should be made connected in some way to become usefull inputdata for the program. Up till now this was done by adding so called systematics to the inputdata: binding energies of two protons or two neutrons, alpha- and (double) beta-decay energies were used since they will be influenced only slightly by paring energies. Values were calculated by manual extrapolation in the graphs for the four quantities simulteneously. Today some thousand systematic data are necessary to connect all the available data so this procedure has become a very time consuming part of the preparation. In this paper an attempt is presented to computerize this part of the work.