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power voltages. The result of this standardization s generates a logic signal if TRUE and no signal if
that any NIM module fits in any NIM bin, therefore, FALSE.
the modules can used to create different
electronic systems for different applications, by E. Gate and Delay Generator: This device
combining them accordingly in a NIM bin, and generates variable-width gate pulses ranging
cabling properly. from a few nanoseconds to as long as a few
seconds.
The two possible states of a logic signal are
standardized by the NIM convention: One logic F. Delay Box: It provides adjustable delays which
state is taken as 0V, and the other one is fixed at a permit a lengthening or shortening of the
specific voltage level, usually 1V. As a general rule, electrical paths in a circuit. The boxes generally
the analog signals from radiation detectors like consist of variable lengths of cable which in a
scintillators, are changed into logic signals at some normal NIM module allow a 0-64ns delay.
point in the electronics chain. This can be
performed by sending the signal through a module G. Scaler or Counter: It counts the number of pulses
called "Discriminator", which tests the amplitude of fed into its input and presents this information on
the analog signal for a minimum height, if the pulse a visual display. In general, it requires a properly
has an amplitude bigger than the minimum, then a shaped signal to function correctly, thus it is
logic signal (yes) is issued, otherwise no signal is usually necessary to have a discriminator
produced (no). process the signals from the detector before
they can be counted by the scaler.
A variety of electronic modules exist for signal
processing, some treat analog signals, others logic Appendix B. Materials
signals, and some can treat both. Some of these
modules and their function are presented below. B.1. NIM Modules

A. Fan-out: Allows the distribution of the signal to A list of the specific NIM modules employed for
several parts of an electronics system by dividing these experiments can be found below.
the input signal into several identical signals of
the same height and shape. A. Fan-in/Fan-out: LeCroy NIM Model 428F Quad
Linear Fan-In/Fan-Out.
B. Discriminator: This device responds only to input
signals with a pulse height higher than a certain B. Discriminator: CAEN N840 8 Channel leading
threshold value, usually set by the user. If this edge discriminator.
criterion is satisfied the discriminator issues a
standard logic signal. Their most common use is C. Logic Fan-in/Fan-out: LeCroy NIM Model 429A
to block out low amplitude noise pulses from Quad Mixed Logic Fan-In/Fan-Out.
photomultipliers. Good pulses, which should be
large enough to trigger the discriminator, are D. Delay Box: ORTEC Model DB463 Delay Box.
then transformed into logic pulses for further
processing. In this role, the discriminator is E. Coincidence Unit: LeCroy NIM Model 465 Triple
essentially a simple analog-to-digital converter. 4-fold Coincidence Unit.

C. Time to Amplitude Converters (TAC): Unit that F. Gate and Delay Generator: Technoland
converts a time period between two logic pulses Corporation N-TM 205, 8 Channel Gate and
into an output pulse whose amplitude is Delay Generator.
proportional to this duration. This pulse may then
be analyzed by a multichannel analyzer to give G. TAC: ORTEC Time to Pulse Height Converter
a spectrum as a function of the time interval. A Model 437A.
time measurement by the TAC is triggered by a
START pulse and halted by a STOP signal. All these modules were assembled inside an
ORTEC 4001A BIN.
D. Coincidence Unit: Determines if two or more
logic signals are coincident in time and

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Tlahuizcalli ISSN: 2448-7260 Año 10 Núm. 30 septiembre-diciembre 2024