Neutron Capture Gamma-Ray Spectroscopy

The post World War II era witnessed a tremendous growth in the research carried out in neutron-induced reactions and especially in neutron capture y-ray studies. This growth was stimulated by the availability of neutron sources, such as reactors and accelerators, and by the development of high resolution y-ray and conversion electron detectors. Today the combination of high flux reactors and precise instrumentation has produced spectral data of exceptional quality, as the pages of these proceedings illustrate. The world-wide community of the practioners of the art of cap­ ture y-ray spectroscopy has met three times in the last decade: the first international symposium on this subject was held at Studsvik, Sweden in 1969, and the second at Petten, The Netherlands in 1974. A smaller meeting, of mostly u. S. and some European parti­ cipation, was held at Argonne National Laboratory in 1966. A perusal of the proceedings of these meetings shows the striking ad­ vances in this now mature field of physics over the last dozen years. Each meeting has seen a small but perceptible increase in the number of papers presented and the number of laboratories repre­ sented. More importantly, each meeting has documented the increasing impact of (n,y) reasearch, not only on other areas of basic physics, but also on commercial and medical applications of this technology. A total of 29 invited papers and 97 contributed papers were presented at this symposium.

Invited Papers.- Some Recent Developments in Nuclear Models.- The Interacting Boson Model.- Investigating Nuclear Structure with the (n,?) Reaction.- Experimental Tests of Recent Nuclear Models with the (n,?) Reaction.- The Complementarity Between Neutron Capture and Heavy-Ion Reactions in Nuclear Structure Studies.- Resonance-Averaged (n,?) Spectra and their Applications to Nuclear Structure.- High Precision (n,e?) Spectroscopy.- Few Quasi-Particle Components of Nuclear States at High Excitation Energies.- Photon Strength Functions.- Distribution of Radiative Strength with Excitation Energy: The E1 and M1 Giant Resonances.- Localized Dipole and Quadrupole Radiation Strengths in 208pb.- Locating Giant Resonances with Photoneutrons.- N-P Capture and the Photo-disintegration of the Deuteron.- Nonstatistical Effects in Neutron Capture, A Review of Recent Experiments.- Doorway Structures in the Radiative Capture of Fast Neutrons.- Fast Neutron Capture Gamma Rays.- Direct and Resonance Capture Reactions with Nucleons and Composite Particles.- Exotic Atoms and Nuclear Structure.- Tests of Quantum Electrodynamics with Neutron Capture Gamma-Rays.- Searches for Parity Violation.- Polarized Beams.- Photon Scattering Studies with N-Capture ? Rays.- Precise ?-Ray Energy Standards.- Practical Applications of Neutron Capture Gamma Rays.- Application of the Thermal (n,?) Reaction to Elemental Analysis.- Resonance Capture Reactions with a Total Energy Detector.- New Instruments and Techniques in Neutron Capture Studies.- High Intensity Neutron Sources.- Contributed Papers.- Experiments and Results at the Ultra-Cold Neutron Source at the ILL, Grenoble.- Analysis of the ?-Particle Spectra from them 143Nd(nth,??)140Ce and 123Te(nth,??)l20Sn Reactions.- Partial ?-Decay Widths of the Thermal Neutron Capture States in 144Nd and 124Te.- Neutron Capture Mechanism in the 3s Size Resonance - I.- Neutron Capture Mechanisms in the 3s Size Resonance - II.- Non-Statistical Neutron Capture Mechanisms in 139La and 141Pr.- Search of an Electric Dipole Moment by Means of Ultra-Cold Neutrons.- Neutron-Capture Prompt Gamma-ray Activation Analysis: Multi-Element Measurements on Various Materials.- A Systematic Search for and Study of (nth,??) and (nth,?p) Reactions.- Precision Measurements of X-Ray Energies, Natural Widths and Intensities in the Actinide Region.- Shape of the El Strength Function in the Region of Pygmy Anomaly Due to Non Statistical Background Coupling.- Gamma Spectra from 233U, 235U and 239Pu During Thermal Neutron Irradiation.- Study of the Energy Levels of 196Au Using the (?,n) Reaction.- Photoexcitation of the 7632 keV Level in 207Pb.- Study of Low-Lying States in 110Ag Following 109Ag(n,?) Reaction.- The 115Sn(n,?) Reaction with Thermal Neutrons.- Systematics of Fragmentation of Nilsson Strength Near A=190.- Test of Microscopic Isovector Optical Potential in Capture and Scattering of Fast Neutrons on 208Pb.- Negative-Parity States in 196Pt.- A Simple Empirical Method for Determining the Energy Gap in Non-Spherical Even-Even Nuclei.- Low-Lying Levels of 236U from Investigation of the K? = 4? Two-Quasineutron Isomer in (n,?) and (n,e) Experiments.- Low Energy ? Rays from Resonance Neutron Capture in 191Ir.- On Parity Violation in Compound Nuclei.- State of High Intrinsic Excitation in 168Er Observed through Thermal Neutron Capture.- Polarized Neutron Capture in Aluminium.- Direct-Semidirect and Pure-Resonance Model Calculations of Fast Neutron Capture on 208Pb.- E.M. Isotope Separation and In-Beam Electron Spectroscopy.- Equipment Designs for Neutron Capture Gamma Experiments with 252Cf.- Upper Limit for the 1H(n,??)2H Cross Section.- Gamma-Ray Strength Functions for Medium Weight Nuclei.- A ‘Super-Thermal’ Source for Ultra-Cold Neutrons.- The 1H(n,?) Reaction Gamma-Ray Energy: Revised Neutron Binding Energies for 3T, 13C, 14C and 15N.- Gamma-Ray Energies from the 14N(n,?) Reaction.- The Role of Neutron-Capture Gamma-Rays in Element Analysis.- Excited Levels in 249Cm from Neutron Capture ?-Ray Measurements.- The 170(?,no)16O Reaction and the Lane-Lynn Theory of Radiative Capture.- Parity Assignments from High Resolution Neutron Scattering and Ml Radiative Strength in 208Pb.- An On-Line Angular Correlation System at the Institut Laue-Langevin; Multipole Mixing in the Gamma to Ground Bands of 164Dy.- Gamma-Ray Strength Functions in 170Tm and 198Au.- Gamma-Decay of P3/2 Neutron Resonances in 28Si.- Rayleigh Scattering of N-Capture ? Rays.- Capture of 2 and 24 keV Neutrons by the Zirconium Isotopes.- Gamma Rays from the 5.9 keV Resonance in 27A1.- Study of Nuclear Levels in 238Np by Reaction Spectroscopy.- Analysis of Fluctuations of Low-Lying State Populations in Radiation Neutron Capture.- Calculation of Neutron Capture Gamma-Ray Spectra.- Study of the 45Sc($$\overrightarrow n $$,?) Reaction.- The Average E1/M1 Strength Ratio for A < 100.- Spin Assignments of 198Au Levels Based On Angular Distribution and Circular Polarization Measurements in the 197Au(n,?) Reaction.- Absolute Intensities of Radiative Deexcitation of 46Sc.- 90Zr(n,?) Studies with Thermal Neutrons.- New External Thermal Facility at NRU and 17O(n,?)18O Reaction Studies.- On-Line Neutron Capture Gamma Analysis with a Ge Detector.- Conversion Electrons and Multipolarities of Transitions in 108Ag.- A Survey of Photon Strengths from A=20 to 240.- Doorway Structures in the Radiative Capture of Fast Neutrons.- Selection of Optimum Neutron Source Size for Neutron Capture Gamma Ray Borehole Analysis.- Experimental Demonstration of Phase Relation for Common Doorway States.- Enhanced Primary Ml Transitions in 207Pb.- The Angular Distribution of the Polarization of Ground State Photoneutrons from 16O.- Evidence for Neutron Capture Through Doorway States in 29Si.- 16.3 eV Neutron Capture in 107Ag: Nuclear Structure of 108Ag.- Fuel Material Analysis Using Radioactive Thermal Neutron Capture.- Anomalous M-l Strengths and Doorway States in Neutron Capture.- A Phase Transition Between N ? 116 and N ? 118 80evenHg Nuclei; Evidence for Possible Triaxial Shape of Even-A Mercury Nuclei.- On the Nature of the Low Lying Collective Levels in 80evenCd Nuclei.- M-l Giant Resonance and Radiative Strength Functions in 126Te.- Low-Lying Levels in 154Eu From Thermal Neutron Capture.- The 59Ni(n,?) Reaction with Thermal Neutrons.- Evidence for an E2 Resonance Observed by Radiative Capture of Fast Neutrons by 40Ca.- Statistical Model Calculation of the Total Radiative Width and the Degree of Freedom in the Capture Process.- Measurement of Thermal Neutron Capture Gamma-Rays Using a Neutron Guide Tube.- Collective Ml Excitation Effects on Photon Angular Distributions from the 140Ce(n,?o) Reaction.- Gamma-Gamma Angular Correlation Measurements on 142Ba.- Use of Nuclear Photon Scattering for Studying the Vibrational Energy of 15N in BN and NH4Cl.- Delayed Coincidence Measurement of 152Eu 89.8488 keV Isomeric State Feeding.- Evaluation of the Capture Cross Section of 169Tm from 10?5 eV to 2.107 eV.- Low-Spin Odd Parity States in 109Pd and Rotation-Aligned Models.- In Situ Capture Gamma Analysis of Large Mineral Samples.- Neutron Capture Gamma-Ray Study at Tehran Nuclear Research Center.- Investigation of 153Gd and of Other Gadolinium Isotopes.- Focussed 24 keV Filtered Neutron Beam.- Levels in 155Gd Populated by Thermal Neutron Capture.- Low-Energy ?-Ray Transitions Between Compound States.- Neutron Capture Cross Sections in 66Zn and 68Zn.- Nuclear Information to the Study of the Electron Configuration of the 4+ Uranium Ion.- Low-Energy Level Structure of by the 151Sm(n,?)151Sm Reaction.- Medical Application of Neutron Capture ?-Ray Spectroscopy: Measurement of Cadmium and Nitrogen in Living Human Subjects.- Vibrational Versus Rotational Descriptions of 193Au.- Correlations Between (n,?) and (d,p) Strengths on 144sm.- The Level Structure of l93Os.- Capture ?-Rays and Reaction Mechanism in 100Mo + N.- Correlation of the Primary Gamma-Ray Intensities Following s- and p-wave Neutron Capture in 58Fe.- Excited Levels in 231Th From Neutron Capture ?-Ray Measurements.- Nuclear Deformation Potential Energy of Odd Tl, Au, Ir and Re Isotones.- Measurement of ?n/?f From Photofission of 238U with Neutron Capture ? Rays.- Fractional Independent Yield of 134I from Photofission of 238U with Neutron Capture ? Rays.- Concluding Remarks.- of After Dinner Speaker.- Personal Reminiscences from the Cavendish in the Thirties.- Participants.- Author Index.- CINDA Index.