ANALYSIS OF POSITRON-ANNIHILATION LIFETIME DATA BY NUMERICAL LAPLACE INVERSION - CORRECTIONS FOR SOURCE TERMS AND ZERO-TIME SHIFT ERRORS

被引:94
作者
GREGORY, RB
机构
[1] Department of Chemistry, Kent State University, Kent
基金
美国国家科学基金会; 美国国家卫生研究院;
关键词
D O I
10.1016/0168-9002(91)90367-Y
中图分类号
TH7 [仪器、仪表];
学科分类号
0804 ; 080401 ; 081102 ;
摘要
We have described modifications to the program CONTIN [S.W. Provencher, Comput. Phys. Commun. 27 (1982) 229[ for the solution of Fredholm integral equations with convoluted kernels of the type that occur in the analysis of positron annihilation lifetime data [R. B. Gregory and Yongkang Zhu, Nucl. Instr. and Meth. A290 (1990) 172]. In this article, modifications to the program to correct for source terms in the sample and reference decay curves and for shifts in the position of the zero-time channel of the sample and reference data are described. Unwanted source components, expressed as a discrete sum of exponentials, may be removed from both the sample and reference data by modification of the sample data alone, without the need for direct knowledge of the instrument resolution function. Shifts in the position of the zero-time channel of up to half the channel width of the multichannel analyzer can be corrected. Analyses of computer-simulated test data indicate that the quality of the reconstructed annihilation rate probability density functions is improved by employing a reference material with a short lifetime and indicate that reference materials which generate free positrons by quenching positronium formation (i. e. strong oxidizing agents) have lifetimes that are too long (400-450 ps) to provide reliable estimate of the lifetime parameters for the shortlived components with the methods described here. Well-annealed single crystals of metals with lifetimes less than 200 ps, such as molybdenum (123 ps) and aluminum (166 ps) do not introduce significant errors in estimates of the lifetime parameters and are to be preferred as reference materials. The performance of our modified version of CONTIN is illustrated by application to positron annihilation in polytetrafluoroethylene.
引用
收藏
页码:496 / 507
页数:12
相关论文
共 24 条
[1]   THE USE OF TRANSFORMATIONS [J].
BARTLETT, MS .
BIOMETRICS, 1947, 3 (01) :39-52
[2]   INVESTIGATION OF THE PHASE-TRANSITIONS AND TEMPERATURE BEHAVIOR OF PTFE BY THE POSITRON LIFETIME TECHNIQUE [J].
BREITENHUBER, L ;
KINDL, P ;
SORMANN, H ;
PUFF, W .
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH, 1982, 199 (1-2) :143-146
[3]   PULSEFLUORIMETRY OF TYROSYL PEPTIDES [J].
GAUDUCHON, P ;
WAHL, P .
BIOPHYSICAL CHEMISTRY, 1978, 8 (01) :87-104
[4]  
GAUTSCHI W, 1972, HDB MATH FUNCTIONS, pCH5
[5]  
Gregory R.B., 1988, POSITRON ANNIHILATIO, P524
[6]   ANALYSIS OF POSITRON-ANNIHILATION LIFETIME DATA BY NUMERICAL LAPLACE INVERSION WITH THE PROGRAM CONTIN [J].
GREGORY, RB ;
ZHU, YK .
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION A-ACCELERATORS SPECTROMETERS DETECTORS AND ASSOCIATED EQUIPMENT, 1990, 290 (01) :172-182
[7]   ANALYSIS OF FLUORESCENCE DECAY KINETICS BY METHOD OF LEAST-SQUARES [J].
GRINVALD, A ;
STEINBER.IZ .
ANALYTICAL BIOCHEMISTRY, 1974, 59 (02) :583-598
[8]  
JEAN YC, 1988, STUDIES PHYSICAL THE, V57, pCH3
[9]   PROGRAM SYSTEM FOR ANALYZING POSITRON LIFETIME SPECTRA AND ANGULAR-CORRELATION CURVES [J].
KIRKEGAARD, P ;
ELDRUP, M ;
MOGENSEN, OE ;
PEDERSEN, NJ .
COMPUTER PHYSICS COMMUNICATIONS, 1981, 23 (03) :307-335
[10]   ANALYZING THE DISTRIBUTION OF DECAY CONSTANTS IN PULSE-FLUOROMETRY USING THE MAXIMUM-ENTROPY METHOD [J].
LIVESEY, AK ;
BROCHON, JC .
BIOPHYSICAL JOURNAL, 1987, 52 (05) :693-706