NIM - AbsoluteAstronomy.com

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 Gnd
35	Reset (scaler)	36	Gate
37	Reset (aux)	38	Coaxial
39	Coaxial	40	Coaxial
41	117 V AC (neutral)	42	High Quality Gnd
G	Gnd Guide Pin

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

Particle physics

Particle physics is a branch of physics that studies the existence and interactions of particles that are the constituents of what is usually referred to as matter or radiation. In current understanding, particles are excitations of quantum fields and interact following their dynamics...

and nuclear

Nuclear physics

Nuclear physics is the field of physics that studies the building blocks and interactions of atomic nuclei. The most commonly known applications of nuclear physics are nuclear power generation and nuclear weapons technology, but the research has provided application in many fields, including those...

physics. The concept of module

Module

Module or modular may refer to the concept of modularity. It may also refer to:-Computing and engineering:* Modular design, the engineering discipline of designing complex devices using separately designed sub-components...

s in electronic systems

Electronic Systems

Electronic systems are groupings of electronic circuits and components which are designed to accomplish one or more complex functions. Examples include telecommunication systems, computer systems, power distribution systems, radar systems, electronic music systems, and many others.Electronic...

offers enormous advantages in flexibility, interchange of instruments, reduced design effort, ease in updating and maintaining the instruments.

The NIM standard is the first (and perhaps the simplest) such standard. First defined by the U.S. Atomic Energy Commission

United States Atomic Energy Commission

The United States Atomic Energy Commission was an agency of the United States government established after World War II by Congress to foster and control the peace time development of atomic science and technology. President Harry S...

'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, ADC

Analog-to-digital converter

An analog-to-digital converter is a device that converts a continuous quantity to a discrete time digital representation. An ADC may also provide an isolated measurement...

s, DAC

Digital-to-analog converter

In electronics, a digital-to-analog converter is a device that converts a digital code to an analog signal . An analog-to-digital converter performs the reverse operation...

s, discriminators, etc.), which plug into a larger chassis (NIM crate, or NIM bin). The crate must supply ±12 and ±24 volt

Volt

The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...

s DC

Direct current

Direct current is the unidirectional flow of electric charge. Direct current is produced by such sources as batteries, thermocouples, solar cells, and commutator-type electric machines of the dynamo type. Direct current may flow in a conductor such as a wire, but can also flow through...

power to the modules via a backplane

Backplane

A backplane is a group of connectors connected 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 as a backbone to connect several printed circuit boards together to make up a complete...

; the standard also specifies ±6 V DC and 220 V or 110 V AC

Alternating current

In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....

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.

The NIM standard also specifies cabling, connectors, impedances

Electrical impedance

Electrical impedance, or simply impedance, is the measure of the opposition that an electrical circuit presents to the passage of a current when a voltage is applied. In quantitative terms, it is the complex ratio of the voltage to the current in an alternating current circuit...

and levels for logic

Boolean logic

Boolean algebra is a logical calculus of truth values, developed by George Boole in the 1840s. It resembles the algebra of real numbers, but with the numeric operations of multiplication xy, addition x + y, and negation −x replaced by the respective logical operations of...

signals. The fast logic standard (commonly known as NIM logic) is a current based logic, with negative true (at -16 mA into 50 ohms = -0.8 Volts); an ECL

Emitter-coupled logic

In electronics, emitter-coupled logic , is a logic family that achieves high speed by using an overdriven BJT differential amplifier with single-ended input, whose emitter current is limited to avoid the slow saturation region of transistor operation....

-based logic is also specified.

Apart from the above mentioned mechanical/physical and electrical specifications/restrictions, the individual is free to design his 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

VMEbus is a computer bus standard, originally developed for the Motorola 68000 line of CPUs, but later widely used for many applications and standardized by the IEC as ANSI/IEEE 1014-1987. It is physically based on Eurocard sizes, mechanicals and connectors , but uses its own signalling system,...

. 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 which do not require digital data communication but benefit from a backplane connector that is better suited for high power use.

See also