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Manuscript Title: DELTA: a computer program to analyze gamma-gamma angular correlations from unaligned states.
Authors: L.P. Ekstrom
Program title: DELTA
Catalogue identifier: ACCL_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 32(1984)399
Programming language: Fortran.
Computer: NORSK DATA ND-500.
Operating system: SINTRAN III, VSE/500, VERSION G.
RAM: 6K words
Word size: 32
Peripherals: disc.
Keywords: Nuclear physics, Gamma ray, Gamma-gamma angular Correlations, Multipole mixing ratios, Spin/parity assignments, Chi-square analysis, Scattering, Activity detection.
Classification: 17.6.

Nature of problem:
The measurement of gamma-gamma angular correlations from radioactive decay and from thermal-neutron capture is an important tool in determining spins of levels and multipole mixing ratios of gamma-ray transitions.

Solution method:
For given data (A2 and A4 coefficients, restrictions on values of multipole mixing ratios and conversion coefficient data) and for a given spin sequence, the program determines, by a x**2 analysis, the possible values of the mixing ratios, with their associated uncertainties.

Restrictions:
No triple correlations. Since the angular correlation coefficients are calculated by the program, there are no restrictions on the multipolarities involved other than that the transitions must be a mixture of a maximum of two multipolarities L and L+1, where L is the lowest multipolarity compatible with the spin difference. The maximum level spin allowed is 20, except when unobserved transitions are involved. For the latter case the maximum spin is 10. These limitations are valid if the computer can handle double precision reals up to 10**76. The maximum number of unobserved transitions (with fixed mixing ratio) is three.

Running time:
Approximately 8 seconds per spin sequence with two mixing ratios varied.