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Manuscript Title: ANNA: an interactive program for analysis of one-dimensional pulse- height spectra.
Authors: P.A. Assimakopoulos, S. Kossionides
Program title: ANNA
Catalogue identifier: ABMN_v1_0
Distribution format: gz
Journal reference: Comput. Phys. Commun. 11(1976)37
Programming language: Fortran.
Computer: PDP-15.
Operating system: ADSS-15, KM15 V5A.
RAM: 16K words
Word size: 18
Peripherals: magnetic tape.
Keywords: Nuclear physics, Analysis, Gamma-ray, Charged particle, Stripping, Peak analysis, Gaussian fit, Background fit, General experiment.
Classification: 17.4.

Nature of problem:
The program is an aid in the analysis of one-dimensional nuclear data (e.g. gamma-ray spectra). It can however be used in all cases, where histogram-type data with Poisson Statistics is analyzed.

Solution method:
Interactive computation is employed. A portion of the data is displayed on a CRT-screen, the area of interest is indicated with the lightpen and various processing commands are executed by changing the state of the ACCUMULATOR SWITCHES. A log of all operations and results is printed on the teletype. Commands already programmed are: Control of I/O, polynomial fit to background, centroid and area of peaks, multiple (1 to 3) gaussian fit. The correct statistical errors are computed and printed along with the parameter values.

A symmetric gaussian is fitted to the data. Thus, fits to multiple peaks with high and low energy tails should be accepted with some caution.

Unusual features:
The program is designed to run on a PDP-15 computer with the minimum of peripheral equipment, notably without a card reader or lineprinter - as is usually the case for such computers employed mainly for on-line data acquisition. (If however a lineprinter is available it can be readily employed by assigning prior to execution I/O device #2 to the lineprinter. In such a case a complete log of the operations will be kept on the lineprinter). Due to this restriction the source program is available in the form of a DECTape. The DECTape contains all source (SRC) and Binary (BIN) programs, as well as the appropriate XCT and XCU files, compiled under the CHAIN system for single-command execution. The source program is also available as a card deck.

Running time:
The program is interactive and runs until stopped by the user/operator. The longest single operation recorded up to now was a double gaussian fit to a structure extending over 128 channels which took four minutes (five iterations).