Short Nuclear Instrumentation Crate - side view

The Nuclear Instrumentation Module (NIM) standard defines mechanical and electrical specifications for electronics modules used in experimental

particle In the physical sciences, a particle (or corpuscle in older texts) is a small localized object which can be described by several physical or chemical properties, such as volume, density, or mass. They vary greatly in size or quantity, from s ...

and

nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies th ...

. The concept of modules in electronic systems offers enormous advantages in flexibility, interchange of instruments, reduced design effort, ease in updating and maintaining the instruments. The NIM standard is one of the first (and perhaps the simplest) such standards. First defined by the U.S. Atomic Energy Commission's report TID-20893 in 1968–1969, NIM was most recently revised in 1990 (DOE/ER-0457T). It provides a common footprint for electronic modules (amplifiers, ADCs, DACs, CFDs, etc.), which plug into a larger chassis ( NIM crate, or NIM bin). The crate must supply ±12 and ±24

volt The volt (symbol: V) is the unit of electric potential, Voltage#Galvani potential vs. electrochemical potential, electric potential difference (voltage), and electromotive force in the International System of Units, International System of Uni ...

s DC power to the modules via a

backplane A backplane or backplane system is a group of electrical connectors in parallel with each other, so that each pin of each connector is linked to the same relative pin of all the other connectors, forming a computer bus. It is used to connect s ...

; the standard also specifies ±6 V DC and 220 V or 110 V AC pins, but not all NIM bins provide them. Mechanically, NIM modules must have a minimum standard width of 1.35 in (34 mm), a maximum faceplate height of 8.7 in (221 mm) and depth of 9.7 in (246 mm). They can, however, also be built in multiples of this standard width, that is, double-width, triple-width etc.W. R. Leo, ''Techniques for Nuclear and Particle Physics Experiments – A How-to Approach''. 1994. The NIM standard also specifies cabling, connectors, impedances and levels for

logic Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the study of deductively valid inferences or logical truths. It examines how conclusions follow from premises based on the structure o ...

signals. The fast logic standard (commonly known as NIM logic) is a current-based logic, negative "true" (at −16 mA into 50 ohms = −0.8 volts) and 0 mA for "false"; is also specified. Apart from the above-mentioned mechanical/physical and electrical specifications/restrictions, the individual is free to design their module in any way desired, thus allowing for new developments and improvements for efficiency or looks/aesthetics. NIM modules cannot communicate with each other through the crate backplane; this is a feature of later standards such as CAMAC and

VMEbus VMEbus (Versa Module Eurocard bus) is a computer bus standard physically based on Eurocard sizes. History In 1979, during development of the Motorola 68000 CPU, one of their engineers, Jack Kister, decided to set about creating a standar ...

. As a consequence, NIM-based ADC modules are nowadays uncommon in nuclear and particle physics. NIM is still widely used for amplifiers, discriminators, nuclear pulse generators and other logic modules that do not require digital data communication but benefit from a backplane connector that is better suited for high-power use.

Standard pin assignments

{, class="wikitable" , + NIM standard module connector pin assignments (required by DOE/ER-0457T) ! Pin # !! Function !! Pin # !! Function , - , 1 , , Reserved 3 V, 2 , , Reserved ��3 V, - , 3 , , Spare bus , 4 , , Reserved bus , - , 5 , , Coaxial , 6 , , Coaxial , - , 7 , , Coaxial , 8 , , 200 V DC , - , 9 , , Spare , 10 , , +6 V , - , 11 , , −6 V , 12 , , Reserved bus , - , 13 , , Spare , 14 , , Spare , - , 15 , , Reserved , 16 , , +12 V , - , 17 , , −12 V , 18 , , Spare bus , - , 19 , , Reserved bus , 20 , , Spare , - , 21 , , Spare , 22 , , Reserved , - , 23 , , Reserved , 24 , , Reserved , - , 25 , , Reserved , 26 , , Spare , - , 27 , , Spare , 28 , , +24 V , - , 29 , , −24 V , 30 , , Spare bus , - , 31 , , Spare , 32 , , Spare , - , 33 , , 117 V AC (hot) , 34 , , Power-return ground , - , 35 , , Reset (scaler) , 36 , , Gate , - , 37 , , Reset (aux) , 38 , , Coaxial , - , 39 , , Coaxial , 40 , , Coaxial , - , 41 , , 117 V AC (neutral) , 42 , , High-quality ground , - , G , , Ground guide pin , , , ,

References

Experimental particle physics

Standard pin assignments

See also

References