Three photo plates derived with spectrograph LNP JINR with constant magnetic field [1] have been investigated using the Microscope Automatic Scanning MAS [2]. Electron internal conversion (ICE) spectrograms of two erbium (Er P-2, Er P-8) and one Ho fractions has been measured. More detailed analysis gave us the possibility to obtain some new lines (see table) in addition to many earlier existing lines in 160Dy [3]. For that investigations it is necessary to increase the speed with which microscopic objects are measured are described. These efforts include the modernization of the MAS automatic scanning microscope and the development of programs to reach an initial point and for carrying out automatic point-to-point linear transitions with a specified step. The error in realizing a transition to a given point with specified coordinates is shown to amount to 1 µm.

The low-lying 0+ excited states remain an object of particular interest in the nuclear structure physics. Recently long sets of 0+ excited states were experimentally observed. Our analysis of the experimental data have shown that in even-even nuclei of the rare-earth and actinide regions the energies of all low lying 0+ excited states with great accuracy can be distributed on parabolic functions of the number of monopole excitations building these states. Along with the classification of the energies of the 0+ excited states in respect to the number of bosons that build the band heads we analyze the role of their collectivity in the structure and evolution of the yrast bands and the B(E2) transition probabilities within these bands. The experimental determination in 160Dy of the predicted in this way 0+ excited state with energy 0.6813 MeV is presented.

Efforts to increase the speed with which microscopic objects are measured are described. These efforts include the modernization of the MAS-1 automatic scanning microscope and the development of programs to reach an initial point and for carrying out automatic point-to-point linear transitions with a specified step. The error in realizing a transition to a given point with specified coordinates is shown to amount to 1 μm.

A possibility that the 0+ state with the energy of 681.3 keV exists in the 160Dy nucleus is discussed. Calculations based on the interacting vector boson model show that in addition to the known 0+ states with the number of bosons n = 2, 5, 6, and 7 there should exist other states with the number of bosons n = 1, 3, 4, and 8 in 160Dy. It is shown that the peak at the energy 681.3 keV, which we experimentally observed in the 160Dy internal conversion electron spectrum, can be ascribed to the 0+ state with the number of bosons n = 1 or n = 8.

Results of upgrading of MAC-1 setup components are described. It is shown that the optimum conditions for detection of low-intensity spectral lines are ensured by the high sensitivity of the instrument to gradations of photoemulsion blackening and by the high resolution of the optoelectronic channel that forms the image of emulsion grains, in combination with the possibility of varying the spectrogram scanning modes, which has been provided by the upgrading. The upgrading of the instrument opens up new avenues for spectroscopy of internal conversion electrons if sufficient statistics is acquired in an experiment. The efficiency of the proposed procedures is demonstrated by the example of extraction of low-intensity K672.35 160Dy and K673.09 160Dy lines in a spectrogram of internal conversion electrons from erbium fractions.

The reanimation of the investigations dedicated to 0^{+} states energies and E0 transitions between them is provoked by new and more precise experimental techniques that not only made revision of the previous data but also gave a possibility to obtain a great amount of new 0^{+} states energies and conversion electrons data. We suggest one phenomenological model for estimation of the E0 transition nuclear matrix elements. Recently theoretical calculations [1] predicted existence of a 0^{+} state with energy 0.68 MeV in ^{160}Dy nucleus. Powerful enough arguments in favor of existence of 681.3 keV state in ^{160}Dy nucleus are presented.

A method for measuring the spectral lines in an Р-50 photoemulsion plate with a varying background level is described. The β-ray spectrograph of the Joint Institute for Nuclear Research's Laboratory of Nuclear Problems, was used to record the spectra. The plate was exposed to internal-conversion electrons produced by the decay of erbium isotopes (erbium fraction). The spectral measurements were performed using the МАС-1 microscope complex. The distribution of the background level over the plate surface was measured. Using the L-structure of the γ-ray line of 161Ho with an energy of 175.5 keV as an example, it was shown that the accuracy of the intensity measurements was 10% or better. The accuracy in measuring the background level governed the accuracy in identifying the multipolarity of nuclear γ transitions. A precision TV system for data readout based on a 768 × 576 pixel CCD matrix provided a measurement accuracy of 0.5 μm for both coordinates.

The production of electron–photon showers in the shower detector was investigated. The detector is composed of alternating layers of nuclear emulsion and lead with a total thickness of 2.95 radiation units for exposure to a 10-GeV electron beam. By using experimental results, it is possible to identify electrons in the shower detector with a high efficiency.