revised 11/98

1999 PACS, 20. - 29.

Summary of Scheme

21. Nuclear Structure (for nucleon structure, see 14.20.D Properties of protons and neutrons; 13.40 for electromagnetic processes and properties; 13.60.H for deep-inelastic structure functions)
21.10.-k Properties of nuclei; nuclear energy levels (for properties of specific nuclei listed by mass ranges, see 27)
21.10.Dr Binding energies and masses
21.10.Ft Charge distribution
21.10.Gv Mass and neutron distributions
21.10.Hw Spin, parity, and isobaric spin
21.10.Jx Spectroscopic factors
21.10.Ky Electromagnetic moments
21.10.Ma Level density
21.10.Pc Single-particle levels and strength functions
21.10.Re Collective levels
21.10.Sf Coulomb energies
21.10.Tg Lifetimes
21.30.-x Nuclear forces (see also 13.75.C Nucleon-nucleon interactions)
21.30.Cb Nuclear forces in vacuum
21.30.Fe Forces in hadronic systems and effective interactions
21.45.+v Few-body systems
21.60.-n Nuclear-structure models and methods
21.60.Cs Shell model
21.60.Ev Collective models
21.60.Fw Models based on group theory
21.60.Gx Cluster models
21.60.Jz Hartree-Fock and random-phase approximations
21.60.Ka Monte Carlo models
21.65.+f Nuclear matter
***** Exotic atoms and molecules, see 36.10
21.80.+a Hypernuclei
21.90.+f Other topics in nuclear structure (restricted to new topics in section 21)
23. Radioactive Decay and In-beam Spectroscopy (see also 82.55 Radiochemistry)
23.20.-g Electromagnetic transitions
23.20.En Angular distribution and correlation measurements
23.20.Gq Multipole mixing ratios
23.20.Js Multipole matrix elements
23.20.Lv Gamma transitions and level energies
23.20.Nx Internal conversion and extranuclear effects
23.20.Ra Internal pair production
23.40.-s beta decay; double beta decay; electron and muon capture
23.40.Bw Weak-interaction and lepton (including neutrino) aspects
23.40.Hc Relation with nuclear matrix elements and nuclear structure
23.50.+z Decay by proton emission
23.60.+e Alpha decay
23.70.+j Heavy-particle decay
23.90.+w Other topics in radioactive decay and in-beam spectroscopy (restricted to new topics in section 23)
24. Nuclear Reactions: General
24.10.-i Nuclear-reaction models and methods
24.10.Cn Many-body theory
24.10.Eq Coupled-channel and distorted-wave models
24.10.Ht Optical and diffraction models
24.10.Jv Relativistic models
24.10.Lx Monte Carlo simulations (including hadron and parton cascades and string breaking models)
24.10.Nz Hydrodynamic models
24.10.Pa Thermal and statistical models
24.30.-v Resonance reactions
24.30.Cz Giant resonances
24.30.Gd Other resonances
24.50.+g Direct reactions
24.60.-k Statistical theory and fluctuations
24.60.Dr Statistical compound-nucleus reactions
24.60.Gv Statistical multistep direct reactions
24.60.Ky Fluctuation phenomena
24.60.Lz Chaos in nuclear systems
24.70.+s Polarization phenomena in reactions
24.75.+i General properties of fission
24.80.+y Nuclear tests of fundamental interactions and symmetries
24.85.+p Quarks, gluons, and QCD in nuclei and nuclear processes
24.90.+d Other topics in nuclear reactions: general (restricted to new topics in section 24)
25. Nuclear Reactions: Specific Reactions
25.10.+s Nuclear reactions involving few-nucleon systems
25.20.-x Photonuclear reactions
25.20.Dc Photon absorption and scattering
25.20.Lj Photoproduction reactions
25.30.-c Lepton-induced reactions
25.30.Bf Elastic electron scattering
25.30.Dh Inelastic electron scattering to specific states
25.30.Fj Inelastic electron scattering to continuum
25.30.Hm Positron scattering
25.30.Mr Muon scattering (including the EMC effect)
25.30.Pt Neutrino scattering
25.30.Rw Electroproduction reactions
25.40.-h Nucleon-induced reactions (see also 28.20 Neutron physics)
25.40.Cm Elastic proton scattering
25.40.Dn Elastic neutron scattering
25.40.Ep Inelastic proton scattering
25.40.Fq Inelastic neutron scattering
25.40.Hs Transfer reactions
25.40.Kv Charge-exchange reactions
25.40.Lw Radiative capture
25.40.Ny Resonance reactions
25.40.Qa (p,pi) reactions
25.40.Sc Spallation reactions
25.40.Ve Other reactions above meson production thresholds (energies > 400 MeV)
25.43.+t Antiproton-induced reactions
25.45.-z Sup 2 H-induced reactions
25.45.De Elastic and inelastic scattering
25.45.Hi Transfer reactions
25.45.Kk Charge-exchange reactions
25.55.-e Sup 3 H-, sup 3 He-, and sup 4 He-induced reactions
25.55.Ci Elastic and inelastic scattering
25.55.Hp Transfer reactions
25.55.Kr Charge-exchange reactions
25.60.-t Reactions induced by unstable nuclei
25.60.Bx Elastic scattering
25.60.Dz Interaction and reaction cross sections
25.60.Gc Breakup and momentum distributions
25.60.Je Transfer reactions
25.60.Lg Charge-exchange reactions
25.60.Pj Fusion reactions
25.70.-z Low and intermediate energy heavy-ion reactions
25.70.Bc Elastic and quasielastic scattering
25.70.De Coulomb excitation
25.70.Ef Resonances
25.70.Gh Compound nucleus
25.70.Hi Transfer reactions
25.70.Jj Fusion and fusion-fission reactions
25.70.Kk Charge-exchange reactions
25.70.Lm Strongly damped collisions
25.70.Mn Projectile and target fragmentation
25.70.Pq Multifragment emission and correlations
25.75.-q Relativistic heavy-ion collisions (collisions induced by light ions studied to calibrate relativistic heavy ion collisions, should be classified under both 25.75 and the 13 or 25 category appropriate to the light ions)
25.75.Dw Particle and resonance production
25.75.Gz Particle correlations
25.75.Ld Collective flow
25.80.-e Meson- and hyperon-induced reactions
25.80.Dj Pion elastic scattering
25.80.Ek Pion inelastic scattering
25.80.Gn Pion charge-exchange reactions
25.80.Hp Pion-induced reactions
25.80.Ls Pion inclusive scattering and absorption
25.80.Nv Kaon-induced reactions
25.80.Pw Hyperon-induced reactions
25.85.-w Fission reactions
25.85.Ca Spontaneous fission
25.85.Ec Neutron-induced fission
25.85.Ge Charged-particle-induced fission
25.85.Jg Photofission
25.90.+k Other topics in nuclear reactions: specific reactions (restricted to new topics in section 25)
26. Nuclear Astrophysics (see also 95.30 Fundamental aspects of astrophysics)
26.20.+f Hydrostatic stellar nucleosynthesis (see also 97.10.C Stellar structure, interiors, evolution, nucleosynthesis, ages)
26.30.+k Nucleosynthesis in novae, supernovae and other explosive environments
26.35.+c Big Bang nucleosynthesis (see also 98.80.F Origin, formation, and abundances of the elements)
26.40.+r Cosmic ray nucleosynthesis
26.50.+x Nuclear physics aspects of novae, supernovae, and other explosive environments
26.60.+c Nuclear matter aspects of neutron stars
26.65.+t Solar neutrinos
27. Properties of Specific Nuclei Listed by Mass Ranges (an additional heading must be chosen with these entries, where the given mass number limits are, to some degree, arbitrary)
27.10.+h A <_ 5
27.20.+n 6 <_ A <_ 19
27.30.+t 20 <_ A <_ 38
27.40.+z 39 <_ A <_ 58
27.50.+e 59 <_ A <_ 89
27.60.+j 90 <_ A <_ 149
27.70.+q 150 <_ A <_ 189
27.80.+w 190 <_ A <_ 219
27.90.+b 220 <_ A
28. Nuclear Engineering and Nuclear Power Studies
28.20.-v Neutron physics (see also 25.40 Nucleon-induced reactions)
28.20.Cz Neutron scattering
28.20.Fc Neutron absorption
28.20.Gd Neutron transport: diffusion and moderation
28.41.-i Fission reactors
28.41.Ak Theory, design, and computerized simulation
28.41.Bm Fuel elements, preparation, reloading, and reprocessing
28.41.Fr Reactor coolants, reactor cooling, and heat recovery
28.41.Kw Radioactive wastes, waste disposal
28.41.My Reactor control systems
28.41.Pa Moderators
28.41.Qb Structural and shielding materials
28.41.Rc Instrumentation
28.41.Te Protection systems, safety, radiation monitoring, accidents, and dismantling
28.50.-k Fission reactor types
28.50.Dr Research reactors
28.50.Ft Fast and breeder reactors
28.50.Hw Power and production reactors
28.50.Ky Propulsion reactors
28.50.Ma Auxiliary generators
28.52.-s Fusion reactors (for fusion reactor types, see
28.52.Av Theory, design, and computerized simulation
28.52.Cx Fueling, heating, and ignition
28.52.Fa Materials
28.52.Lf Components and instrumentation
28.52.Nh Safety
28.60.+s Isotope separation and enrichment
28.70.+y Nuclear explosions (see also 47.40 Compressional flows; shock and detonation phenomena; for radiation protection from fallout, see 87.52 in biological and medical physics)
28.90.+i Other topics in nuclear engineering and nuclear power studies (restricted to new topics in section 28)
29. Experimental Methods and Instrumentation for Elementary-particle and Nuclear Physics
29.17.+w Electrostatic, collective, and linear accelerators
29.20.-c Cyclic accelerators and storage rings
29.20.Dh Storage rings
29.20.Fj Betatrons
29.20.Hm Cyclotrons
29.20.Lq Synchrotrons
29.25.-t Particle sources and targets
29.25.Bx Electron sources
29.25.Dz Neutron sources
29.25.Lg Ion sources: polarized
29.25.Ni Ion sources: positive and negative
29.25.Pj Polarized and other targets
29.25.Rm Sources of radioactive nuclei
29.27.-a Beams in particle accelerators (for low energy charged-particle beams, see
29.27.Ac Beam injection and extraction
29.27.Bd Beam dynamics; collective effects and instabilities
29.27.Eg Beam handling; beam transport
29.27.Fh Beam characteristics
29.27.Hj Polarized beams
29.30.-h Spectrometers and spectroscopic techniques
29.30.Aj Charged-particle spectrometers: electric and magnetic
29.30.Dn Electron spectroscopy
29.30.Ep Charged-particle spectroscopy
29.30.Hs Neutron spectroscopy
29.30.Kv X- and gamma-ray spectroscopy
29.30.Lw Nuclear orientation devices
***** Energy loss and stopping power, see 34.50.B and 61.85
29.40.-n Radiation detectors (for mass spectrometers, see 07.75)
29.40.Cs Gas-filled counters: ionization chambers, proportional, and avalanche counters
29.40.Gx Tracking and position-sensitive detectors
29.40.Ka Cherenkov detectors
29.40.Mc Scintillation detectors
29.40.Rg Nuclear emulsions
29.40.Vj Calorimeters
29.40.Wk Solid-state detectors
29.50.+v Computer interfaces (for electronic circuits, see 84.30)
29.85.+c Computer data analysis
29.90.+r Other topics in elementary-particle and nuclear physics experimental methods and instrumentation (restricted to new topics in section 29)