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Multiple Coulomb-excitation experiments for $^{156}\mathrm{Gd}$ were made with a 118 MeV $^{32}\mathrm{S}$ beam and a 225 MeV $^{58}\mathrm{Ni}$ beam. The ground-state band, the $\ensuremath{\beta}$ band ($K={0}^{+}$), another $K={0}^{+}$ band, and the $\ensuremath{\gamma}$ band ($K={2}^{+}$) were observed up to the ${18}^{+}$, ${14}^{+}$, ${8}^{+}$, and ${12}^{+}$ states, respectively, while the octupole band ($K={1}^{\ensuremath{-}}$) was observed up to the ${15}^{\ensuremath{-}}$ state, through the analysis of particle-$\ensuremath{\gamma}$-$\ensuremath{\gamma}$ data. Compared with the results of the in-beam $\ensuremath{\gamma}$-ray spectroscopy previously obtained, the present result suggests that a band crossing occurs in the $\ensuremath{\gamma}$ band. As for the $\ensuremath{\beta}$ band, the excitation energy of the ${12}^{+}$ state was revised and the ${14}^{+}$ state was newly observed in the present experiment. The intrinsic matrix elements entering the generalized intensity relations were obtained so as to reproduce the spin dependence of the $E2$ matrix elements extracted from the experimental results of particle-$\ensuremath{\gamma}$ angular correlation for the transitions within each band and between each band and the ground-state band by the least-squares search code gosia. The change of characters in the $\ensuremath{\beta}$ and $\ensuremath{\gamma}$ bands is discussed as a possible cause for the variation of the $E2$ matrix elements in the higher-spin region. The intrinsic matrix elements were also obtained for the $E1$ and $E3$ transitions from the ground-state band to the octupole band with $K={1}^{\ensuremath{-}}$ through analysis by gosia.

A charged particle detector system for Coulomb excitation experiments with the multi-γ-ray detector system, NORDBALL, has been designed and constructed. The system consists of five position sensitive Si detecors and an annular type Si detector, which are installed in the central space of a BaF2 inner ball. The experiments have been carried out by using the beams of 32S, 48Ti and 58Ni ions. The combination of the new charged particle detector system and NORDBALL proves to have an excellent performance for heavy-ion-induced Coulomb excitation experiments.

Excited states in 154,156,158,160 Gd have been populated through the multiple coulomb excitation process by 32 S, 48 Ti, 58 Ni ions. The ground band, γ-band and octupole K π = 0 − band were extended to I π = 16 + , (12 + ), and (11 − ) state respectively in 160 Gd. The octupole K π = 1 − band was extended to I π = 9 − state in 158 Gd. Excitation cross sections of individual levels relative to that of the I π = 4 + state in the ground band in each nucleus were compared with the simulation by the computer code GOSIA within the framework of the pure rotational model. From these comparisons the matrix elements for both intra-band and inter-band transitions were deduced.

Gamma-ray energies of 152Eu were measured with the uncertainties of 1.1–7.3 eV in the region of 290–720 keV using Ge spectrometers. To determine the 719 keV γ-ray energy of 152Eu, we measured the 125 and 592 keV cascade γ-ray energies of 185Os which provide the 717 keV cross-over γ-ray energy. Seven γ-ray energies of 152Eu in the region of 770–1400 keV were obtained from the sum of the cascade γ-ray energies.

The Ps formation rate depends on materials. Especially, the rate in liquid helium is larger than those of other materials. The three-quantum decay component obtained from the energy spectrum is useful for study of the behavior of positrons and Ps in materials. We have developed a simple method to investigate the three-quantum decay rate

Low energy gamma rays following the decay of 177m Lu were investigated by using a high resolution Ge(Li) detector. Level energies of the K =7/2 + [404] band with spins up to 17/2 + in 177 Lu and those of the K =9/2 + [624] band with spins up to 21/2 + in 177 Hf were precisely determined with an accuracy of about 10 eV. Coefficients of the Bohr and Mottelson expression including higher order terms were evaluated from these experimental level energies. This expression reproduces the experimental values with four and five parameters for 177 Lu and 177 Hf, respectively. It was found that the Coriolis terms are negligibly small for the K =7/2 + band and the higher order Coriolis terms are considerably large for the K =9/2 + band. The moment of inertia of the K =7/2 + band increases but that of the K =9/2 + band decreases as the angular frequency increases.

Energies of five gamma rays were measured with Ge(Li) spectrometers which were calibrated by using gamma-ray energy standards of 198 Au and 192 Ir. Observed energies are 477.6064(26) KeV for 7 Be, 511.8562(23) KeV for 106 Ru, 514.0076(22) KeV for 85 Sr, 531.0329(24) KeV for 147 Nd and 569.7035(41) KeV for 207 Bi. These gamma rays are useful for energy standards, especially for the energy measurement of position annihilation radiation.

Energies of positron annihilation radiation from various materials were measured with Ge detectors. Energies of annihilation radiation are clearly smaller than the electron rest mass. The Compton wavelength and the rest mass of electrons were determined to be 2.426310(15) pm and 511003.1 ±3.2 eV, respectively, with correction of the positronium binding energy by using annihilation radiation from ice. For other cases the differences are attributed to the minimum potentials of positrons in material as well as the binding energies of electrons. However, the differences are deviated from the expected values.

The source position effect for gamma-ray pulse heights was investigated with two planar and three coaxial Ge(Li) detectors at the gamma-ray energies of 303 keV, 512 keV and 1275 keV. The peak shift in the pulse height spectrum was measured as a function of the source-to-detector distance and of the source angle from the detector axis. A clear shift of the peak center was observed for the planar detectors, and a smaller shift for the coaxial detectors. It was found that the shift was almost independent of the bias voltage. These experimental results are difficult to explain by the field increment effect and the charge trapping effect in the detector. The rise time effect was not observed in any of the planar detectors.

Method of comparing the positron mass with the electron mass by using crossed fields is discussed on the basis of the relativistic calculation to the second order. Remodeling of a high resolution magnetic β-ray spectrometer into a positron-electron mass spectrometer is proposed. The crossed fields in the β-ray spectrometer equipped with a pair of cylindrical electrodes gives the mass dispersion of 1.3 μm/ppm at the optical circle of 0.75 m radius. Simulated peak profiles are presented for the monochromatic source of electrons or positrons and the β-ray source that emits them simultaneously in the continuous distribution.

Energies of 38 gamma rays in the range 100–460 keV emitted in the decay of 177m Lu were measured precisely with a Ge spectrometer based on the gamma-ray primary energy standards of 169 Yb and 192 Ir. The nonlinearity correction for the spectrometer was obtained from the amplitude of the pulser pulses as determined from the dc voltage measured with a high precision digital voltmeter. Our experiment shows that this method is convenient and capable of determining the gamma-ray energy with an accuracy of 10 ppm or less when based on two standard lines in gamma-ray spectra. The final energy values are obtained from adjustment by the Ritz rule. Forty-three gamma-ray energies were determined within errors of 10 ppm and they are useful for secondary energy standards.

The decay of 124 I was investigated with beta-ray spectrometers and scintillation spectrometers by using carrier-free source produced by 121 Sb (α, n ) 124 I. The intensity ratio of the 1.54 MeV beta component to the 2.15 MeV one was obtained to be 1.07. Internal conversion ratios for the 604 keV gamma transition are K/L=7.3±0.4 and (M+N)/L=0.26±0.07. Internal conversion coefficients were determined to be (3.8± 0.6)×10 -3 , (2.5±0.4)×10 -3 , (7.9±1.5)×10 -4 , (3.3±0.8)×10 -4 , (2.9±0.7)×10 -4 , (2.1±0.4)×10 -4 and (2.1±0.8)×10 -4 for gamma transitions of 0.604, 0.72, 1.32, 1.37, 1.52, 1.69 and 2.08 MeV, respectively. The coefficient A 2 ( W ) in the directional correlation function \(\mathscr{W}\)(θ, W )=1+ A 2 ( W )P 2 (cos θ) was measured for the 2–(1.54 MeV β)2+(0.604 MeV γ)0+ cascade. The result is discussed on the basis of the ξ approximation, the modified B i j approximation and a more accurate method.

Gamma-ray energies lower than 500 keV and relative intensities have been precisely measured with Ge(Li) detectors. Many experimental effects such as the source position effect, the counting rate effect, the room temperature effect, etc. are examined. Results are as follows: 303.916±0.012 and 400.624±0.030 keV for 75 Se; 433.932±0.014 keV for 108 m Ag; 255.126±0.010 (3.33±0.13) and 391.686±0.027 keV (100) for 113 Sn; 364.456±0.031 keV for 131 I; 161 (0.98±0.07), 223 (0.76±0.05), 276 (11.6±0.5), 302.839±0.008 (29.6±1.1), 355.999±0.024 (100) and 383.841±0.027 keV (14.9±0.6) for 133 Ba. Parentheses show relative intensities.

Beta and gamma rays emitted from Ag112 have been investigated using a magnetic beta-ray spectrometer and scintillation spectrometers. The half-life was determined to be 3.14±0.05 h. Maximum energies and relative intensities of beta-rays are 3.94±0.04 MeV (54%), 3.35± 0.08 MeV (22%) and 1.96±0.10 MeV (10%). internal conversion electrons corresponding to 0.610, 0.621, 0.648 and 0.689 MeV gamma rays and other uncertain conversion electrons were found. In single, summing peak, gamma-gamma coincidence and beta-gamma coincidence spectra, twenty six gamma rays were observed. A decay scheme is constructed.

Decay of 80m Br was investigated. The half-lives of the isomeric and the ground states of 80 Br were obtained to be 4.42±0.01 h. and 16.8±0.1 min, respectively. Beta-ray, gamm-ray and gamma-gamma coincidence studies were carried out and energies and relative intensities of beta and gamma transitions were determined. Kurie plot analyses of negatrons and positrons give the maximum energies of 2.000±0.016 MeV and 0.850±0.007 MeV, respectively. The 1.478 MeV 0 + level of 80 Se and the 1.320 MeV 0 + and 1.256 MeV 2 + levels of 80 Kr were confirmed.

Gamma rays and internal conversion electrons following the decay of 8.3 d 106m Ag were studied with Ge(Li) spectrometers and an orange type beta-ray spectrometer. Energies and intensities of some low energy gamma rays were measured precisely. Conversion coefficients for weak and high energy transitions were determined to estimate the multipolarities transitions. New gamma rays of 69, 70, 80, 83, 178, 434, 522, 950, 1051, 1077, 1168, 1178, 1349, 1419, 1909 and 2077 keV were observed. New levels are proposed from some of these gamma rays. Two three-phonon states are suggested on the basis of the observed gamma ray branching ratios to the low-lying two-phonon states.

Common to both static and dynamic patient irradiations at the LAMPF linac is the problem of maintaining good quality control of beams form a secondary channel. A major contributor to therapy beam variation has been change in electron contamination due to the change in target geometry and proton beam steering. The electron variation problem is described and a solution is presented that has been realized as a result o a new target geometry that allows some control of the electron fraction. (GHT)

The energy of the 192Ir 296 keV gamma ray has been measured with the standard of 183Ta by using Ge(Li) detectors. The observed value is 295.949±0.004 keV on the basis of the 1969 physical constants. Other gamma-ray energies of 192Ir are obtained from energy differences of previous measurements and the Ritz rule.