Automatic correction for dead time losses in nuclear counting experiments is implemented by a simple live timer arrangement in which each counting interval is extended for compensation for the dead time during that interval. this method eliminates repetitious manual calculations, source of error, and dependence upon paralysis shifts

Porges, K. G.

Rudnick, S. J.

English

NASA Technical Reports Server

October 1969	 Brief 69-10612 
t% y e
AEC-NASA TECH BRIEF 
TES
AEC-NASA Tech Briefs describe innovations resulting from the research and development program 
of the U.S. AEC or from AEC-NASA interagency efforts. They are issued to encourage commercial 
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the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Live-Timer Method of Automatic

Dead-Time Correction for Precision Counting 
Several applications of live-timer count correction 
are reported (ref. I); they are discussed with regard 
to the precision and statistical accuracy of the re-
sults obtained. The method is compared to conven-
tional real-time operation with subsequent formula 
correction. 
Automatic correction for dead-time losses in nuclear 
counting experiments can often be implemented by 
a simple live-timer arrangement in which each count-
ing interval is extended for compensation for the dead 
time during that interval. In comparison with con-
ventional calculated correction, automatic live-timer 
correction claims four advantages: (I) elimination of 
tedious, repetitious manual calculations when no 
computer is available; (2) elimination of a possible 
source of error, whether or not a computer program 
is employed in processing of counts; (3) elimination of 
any dependence of the result upon paralysis shifts or 
instabilities; and (4) the possibility of immediate 
results, so that a series of counts can be plotted as it 
proceeds and inferences may be drawn quickly. 
For live-timer correction to be widely acceptable, 
particularly for precision counting, the statistics of the 
automatic correction process must not be significantly 
worse than those resulting from the propagation of 
error through the usual correction formula, starting 
with the variance attached to the dead-time loaded 
channel. This is shown to be the case; the statistics 
of live-timer correction are derived on the basis of 
generating functions. For straightforward high-preci-
sion counting, the live-timer method proves to be 
superior.
Counting of sources that decay appreciably during 
the count, sometimes thought to be a case in which 
live-timer correction fails, can be accomplished by 
choice of a certain readily calculable ratio of clock-
inhibit duration to paralysis. Similarly, coincidence 
counting with different channel paralysis is amenable 
to live-timer correction, with a resultant precision 
exceeding that of formula corrections; this is found 
by a slight elaboration of live-timer logic. 
The automatic detection circuitry is coupled to a 
dual-discriminator network and an oscillator-con-
trolled timer. These subsystems serve as input to a 
network of three separate logic-controlled counters 
and a coincidence gate. 
While no system yet devised can cope with pileup 
in a way that would make high-precision counting 
entirely independent of the input rate, a live-timer 
correction system, in conjunction with nonretrigger-
ing discriminator, can at least eliminate other count-
rate and input-spectrum-dependent offset errors that 
are difficult to correct by computation. The system 
is also easier to implement. 
Reference: 
I. Porges, K. G.; Rudnick, S. J.: Live-Timer Method 
of Automatic Dead-Time Correction for Precision 
Counting. Argonne National Laboratory, July 1968. 
Notes: 
I. This innovation may interest designers or manu-
facturers of radiological test equipment.
(conlintied Ot'erleai( 
This document was prepared under the sponsorship of the Atomic 	 liability resulting from the use of the information contained in this 
Energy Commission and/or the National Aeronautics and Space	 document, or warrants that the use of any information, apparatus, 
Administration. Neither the United States Government nor any per- 	 method, or process disclosed in this document may not infringe pri-
son acting on behalf of the United States Government assumes any vately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19690000565 2020-03-16T18:25:34+00:00Z
2. Inquiries concerning this innovation may be di-
rected to:
Office of Industrial Cooperation 
Argonne National Laboratory 
9700 South Cass Avenue 
Argonne, Illinois 60439 
Reference: B69-10612 
Source: K. G. Porges

Reactor Physics Division

S. J. Rudnick
Electronics Division

(ARG- 10478)
Patent status: 
Inquiries concerning rights to commercial use of 
this innovation may be made to: 
Mr. George H. Lee, Chief 
Chicago Patent Group 
U.S. Atomic Energy Commission 
Chicago Operations Office 
9800 South Cass Avenue 
Argonne, Illinois 60439 
r 
Brief 69-10612	 Category 01


Live-timer method of automatic dead-time correction for precision counting

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