FAQ - NIM - SPECS - HISTORY ongoing and updated
Posted: Fri Nov 09, 2001 12:50 pm
All,
Several of us on the list are working with NIM modules and bins in our effort to instrument ourselves for nuclear detection schemes.
What follows is a short history of NIM which while not directly involving fusion will serve to educate others in what it is and how it came to be a standard. I will continuously add to this post as needed.
****** NIM is a contraction or acronym for Nuclear Instrumentation Module ********
By the 1950's it was realized that most all nuclear instrumentation utilized several, common, basic building blocks with only a single or couple of application specific items for each different measurement scheme or system.
The idea came to a number of people that the basic building blocks could be provided in portable, removable modules common to a single cage or rack which would itself have a built in power supply to supply 4 commonly used DC and the standard line AC voltages on a bussed together group of standard amp plugs. The cage and attached power supply would itself fit into a standard 19" rack for laboratory use. The standardized modules could then just slide into the rack on rails and the rear mounted power plugs couple into the modules. The modules could then be linked up in logical order via front or back BNC jacks and cables to make any instrument desired. Neat, huh?
The credit for publishing the first paper to standardize this system goes to Lou Costgrell of the old Atomic Energy Commission who authored the document "Standard Nuclear Instrument Modules" TID-20893.
ORTEC (Oak Ridge Technical Enterprise Corp) offered 17 NIM Modules in their first catalog in 1966. Tennelec (Tennessee Electronics) was also an early supplier of NIM modules. (Bought out by Oxford and then Canberra. Most of the NIM makers are or were clustered in a cozy fashion on the door step of the major national AEC laboratories, which were their prime customers.
The current list of NIM manufacterers past and present follows:
ORTEC (Oak Ridge Technical Enterprises Corp)
Tennelec (Tennessee Electronics)
Canberra
LE (?)
Metronics
ND (Nuclear Data)
Victoreen/Tullamore
LeCroy (LRS)
SRS (Stanford Research Systems)
Tracor-Northern
I need help...Anyone know the letter codes in question marks? Got any Nim Modules made by another maker? Let me know.
ORTEC and Canberra remain the largest suppliers with SRS and a few others hanging in there. Many are gone or have been absorbed. ORTEC is now really part of Perkin Elmer along with the old EG&G.
The NIM bin and its standard slots have also had non-nuclear modules made for it. I have seen, and own, Laser Q switches, pockels cell controllers, and other electro-optical system modules bundled in the Nim module format.
A NIMless future?
With modern computers/laptops becoming a de facto lab standard and modern integrated circuits putting entire, rocket fast, complex systems on a single chip, the large, bulky rack mount NIM system is looking pretty long in the tooth.
Small boxes the size of a pack of cigarettes now plug into the USB port via a cable and you have a complete gamma spectrometer. Jack fields and snarled patch cords are being replaced by software which is multi-faceted and multi-tasking, changing your laptop from a gamma spec. to a mass spec. with a touch of a function key.
NIM is still actively sold, but for how long? A vast amount of surplus NIM is currently on E-bay as one college after another folds up half century old nuclear physics and engineering departments. Others still hanging on are moving into the 21st Century and getting computerized in the lab. (more NIM hittin' th' streets). It is a good time to buy into used NIM.
Nim Connectors/bins/standards......................
"Bin" or NIM frame
This is a rectangular metallic cage designed to mount in the universal 19" professional, vertical, rack mount. When empty, there are 12 slots with 12 guide rails and twelve AMP connector plugs in the rear of the unit designed to interface with an inserted module. The regulation NIM slot width and front plate is 1 3/8" wide. The height is 8 3/4 inches. This latter figure is also the height of the entire bin, thus it takes up about 6R or 6 standard 19" rack unit heights in any rack into which it is installed.
The rear of the bin has a low voltage DC regulated power supply attached. It supplies the following voltages to the following pins on each NIM connector.
+6VDC Pin 10 on modern bins only - not common
-6VDC Pin 11 on modern bins only - not common
+12VDC pin 16
-12 VDC pin 17
+24 VDC pin 28
-24 VDC pin 29
0 VDC pin 34 Common return to all supplies. Metal case of nim bin. GROUND
120VAC pin 41 (neutral)
120VAC pin 33 (hot)
Ground pin 42 (AC ground) High Quality
It is common to find a NIM bin wired for +/-6 volts on the buss and even have test points for these voltages on the front panel. However it is extremely rare to find that the power supply attached will actually deliver the 6 volt levels to the buss. It is an old standard. You can power it up by purchasing a plug in 6 volt module that plugs into the bin and it will supply 6 volt power to the buss.
Signals...........
The logic highs and lows of the original NIM spec are leftovers from discrete transistor wired logic days and are not generally compatible with modern logic families. The book "Building Scientific Apparatus" has some nice simple interfaces for modern TTL and ECL logic families. For more on the book, check out my post , "Building Physics Instruments" in the Books and References forum.
Output jacks of all NIM bins must deliver
logic zero is any voltage between +1volt and -2volts (zero volts is just fine! TTL, CMOS and most modern logic)
logic one is any voltage between +4 volts and +12 volts. ( the 4 volt minimum is a bit steep for drained, un buffered TTL. CMOS is OK)
All Nim module inputs must accept the following
Logic zero - +1.5 volts to -2 volts
Logic one - +3 volts to +12 volts
You can see there is lots of room for noise immunity and a decent guard band between logic levels. All this makes for fairly slow NIM data rates. (slew rates were low in the old days.) The wide logic level ranges made for relatively easy interfacing.
Inspite of the oddball levels, I have not had to build an interfacing circuit yet for "pulled up", clean, TTL signals.
Connectors......
These are made by AMP corp., and in all NIM Racks, (called NIM bins), they are 90% un-populated. That is, there are not even pins or wires connected to them. The extra pins were here for expansion and individual user use for specific signals to their custom application modules.
For standardizing purposes, all low voltages standardized for NIM use are piped to the same numbered pins on all bins and all modules. These are sacred territory, set in stone, not to be tampered with or altered in any way!
NIM modules do not have to be only 1 NIM slot wide. Complicated modules with lots of circuitry or with bulky or wide meters, readouts, etc are commonly found that take up 2 or 5 NIM slots. These wider modules, however, must all be a perfect multiple of the standard NIM module width.
Most connectors on the front panel of the modules as well as those on the rear panel, are standard BNC, RF type signal plugs. The standardized impedance of appropriate cables should be 94 ohms, (very weird), but 50 ohms can play unless loading is an issue. This impedance is common to many instrumentation systems.
Some NIM stuff is 94 ohms (whacko), but 75 ohm cabling can be used provided pulse shape fidelity isn't a major issue.
High voltage NIM bias supplies will usually contain and internal polarity "flipper board" that can be turned about to give either plus or minus HV output, as need.
Some NIM modules, especially single channel analyzers and linear amps, often have a 9 pin "D" standard preamp power plug on the rear panel to power an external preamp. This is normally for a PMT or solid state detector. The pinouts on these for power are fairly standardized, but are not rigidly adhered to across the board. Most are wired as follows
+24 VDC pin 7
-24 VDC pin 6
+12 VDC pin 4
-12 VDC pin 9
common return pin 1
You should check the above pinouts to be sure before pluging in a preamp to avoid problems damaging it or the NIM bin supply. ***NOTE********* Some Tennelec preamps and bins are wired for odd ball 9pin hookups.
More, later.......... check back as I add data.....
Update 2020:
What modules should I get?
Wow! I don't know. What are you trying to do?
For fusor work and neutron detection I use a an external preamp (Princeton Gamma Tech) powered off of the NIM bin's 9 pin connector attached directly to my Reuter and Stokes 3He neutron detection tube.
In the bin, I run the preamp output it to a linear amp module (Ortec)
I then run it through a windowed spectroscopy amplifier(Ortec)
Next I feed the spec amp neutron signal to an (Ortec) digital rate meter module.
I used a dead 1 slot NIM module, that I gutted, to build my own custom audio amp and light flasher to see and hear the individual neutron count detections.
I have a 2000 volt bias supply in the bin to bias the 3He tube (Tennelec)
I can't sit here and enumerate every available module that is out there and what they are used for. NIM is now a relic of the past, (1960's era), that has limped to the 21st century. Electronically it is ancient, but it is still a fine source of electronic, plug-and-play "erector set" components for those who can't make their own electronics based on modern age electronic components using knowledge and a soldering iron. In 1998, (22 years ago), when I started, NIM was the cat's PJ's. Today, using the latest electronics, what I have in my big, heavy, 19-inch rack, NIM bin could be placed in a child's small piggy bank including the 2000 volt power supply!
Modules and bins are where you find them. Let the buyer beware on this stuff, as always. The stuff is old and maybe one seller in 100 knows anything about NIM.
I now add a bit more......this is from our longtime member Rich Feldman. I copied his comments and a very valuable URL which should be looked at by all would-be NIM users. Thank you Rich
Just wanted to point out that NIM and "digital" are not mutually exclusive.
There's plenty of digital functionality available in NIM modules, for example timers and counters and coincidence detectors, with NIM and/or mainstream I/O signaling.
I now, 2022 attach a formal pin diagram
Richard Hull
Several of us on the list are working with NIM modules and bins in our effort to instrument ourselves for nuclear detection schemes.
What follows is a short history of NIM which while not directly involving fusion will serve to educate others in what it is and how it came to be a standard. I will continuously add to this post as needed.
****** NIM is a contraction or acronym for Nuclear Instrumentation Module ********
By the 1950's it was realized that most all nuclear instrumentation utilized several, common, basic building blocks with only a single or couple of application specific items for each different measurement scheme or system.
The idea came to a number of people that the basic building blocks could be provided in portable, removable modules common to a single cage or rack which would itself have a built in power supply to supply 4 commonly used DC and the standard line AC voltages on a bussed together group of standard amp plugs. The cage and attached power supply would itself fit into a standard 19" rack for laboratory use. The standardized modules could then just slide into the rack on rails and the rear mounted power plugs couple into the modules. The modules could then be linked up in logical order via front or back BNC jacks and cables to make any instrument desired. Neat, huh?
The credit for publishing the first paper to standardize this system goes to Lou Costgrell of the old Atomic Energy Commission who authored the document "Standard Nuclear Instrument Modules" TID-20893.
ORTEC (Oak Ridge Technical Enterprise Corp) offered 17 NIM Modules in their first catalog in 1966. Tennelec (Tennessee Electronics) was also an early supplier of NIM modules. (Bought out by Oxford and then Canberra. Most of the NIM makers are or were clustered in a cozy fashion on the door step of the major national AEC laboratories, which were their prime customers.
The current list of NIM manufacterers past and present follows:
ORTEC (Oak Ridge Technical Enterprises Corp)
Tennelec (Tennessee Electronics)
Canberra
LE (?)
Metronics
ND (Nuclear Data)
Victoreen/Tullamore
LeCroy (LRS)
SRS (Stanford Research Systems)
Tracor-Northern
I need help...Anyone know the letter codes in question marks? Got any Nim Modules made by another maker? Let me know.
ORTEC and Canberra remain the largest suppliers with SRS and a few others hanging in there. Many are gone or have been absorbed. ORTEC is now really part of Perkin Elmer along with the old EG&G.
The NIM bin and its standard slots have also had non-nuclear modules made for it. I have seen, and own, Laser Q switches, pockels cell controllers, and other electro-optical system modules bundled in the Nim module format.
A NIMless future?
With modern computers/laptops becoming a de facto lab standard and modern integrated circuits putting entire, rocket fast, complex systems on a single chip, the large, bulky rack mount NIM system is looking pretty long in the tooth.
Small boxes the size of a pack of cigarettes now plug into the USB port via a cable and you have a complete gamma spectrometer. Jack fields and snarled patch cords are being replaced by software which is multi-faceted and multi-tasking, changing your laptop from a gamma spec. to a mass spec. with a touch of a function key.
NIM is still actively sold, but for how long? A vast amount of surplus NIM is currently on E-bay as one college after another folds up half century old nuclear physics and engineering departments. Others still hanging on are moving into the 21st Century and getting computerized in the lab. (more NIM hittin' th' streets). It is a good time to buy into used NIM.
Nim Connectors/bins/standards......................
"Bin" or NIM frame
This is a rectangular metallic cage designed to mount in the universal 19" professional, vertical, rack mount. When empty, there are 12 slots with 12 guide rails and twelve AMP connector plugs in the rear of the unit designed to interface with an inserted module. The regulation NIM slot width and front plate is 1 3/8" wide. The height is 8 3/4 inches. This latter figure is also the height of the entire bin, thus it takes up about 6R or 6 standard 19" rack unit heights in any rack into which it is installed.
The rear of the bin has a low voltage DC regulated power supply attached. It supplies the following voltages to the following pins on each NIM connector.
+6VDC Pin 10 on modern bins only - not common
-6VDC Pin 11 on modern bins only - not common
+12VDC pin 16
-12 VDC pin 17
+24 VDC pin 28
-24 VDC pin 29
0 VDC pin 34 Common return to all supplies. Metal case of nim bin. GROUND
120VAC pin 41 (neutral)
120VAC pin 33 (hot)
Ground pin 42 (AC ground) High Quality
It is common to find a NIM bin wired for +/-6 volts on the buss and even have test points for these voltages on the front panel. However it is extremely rare to find that the power supply attached will actually deliver the 6 volt levels to the buss. It is an old standard. You can power it up by purchasing a plug in 6 volt module that plugs into the bin and it will supply 6 volt power to the buss.
Signals...........
The logic highs and lows of the original NIM spec are leftovers from discrete transistor wired logic days and are not generally compatible with modern logic families. The book "Building Scientific Apparatus" has some nice simple interfaces for modern TTL and ECL logic families. For more on the book, check out my post , "Building Physics Instruments" in the Books and References forum.
Output jacks of all NIM bins must deliver
logic zero is any voltage between +1volt and -2volts (zero volts is just fine! TTL, CMOS and most modern logic)
logic one is any voltage between +4 volts and +12 volts. ( the 4 volt minimum is a bit steep for drained, un buffered TTL. CMOS is OK)
All Nim module inputs must accept the following
Logic zero - +1.5 volts to -2 volts
Logic one - +3 volts to +12 volts
You can see there is lots of room for noise immunity and a decent guard band between logic levels. All this makes for fairly slow NIM data rates. (slew rates were low in the old days.) The wide logic level ranges made for relatively easy interfacing.
Inspite of the oddball levels, I have not had to build an interfacing circuit yet for "pulled up", clean, TTL signals.
Connectors......
These are made by AMP corp., and in all NIM Racks, (called NIM bins), they are 90% un-populated. That is, there are not even pins or wires connected to them. The extra pins were here for expansion and individual user use for specific signals to their custom application modules.
For standardizing purposes, all low voltages standardized for NIM use are piped to the same numbered pins on all bins and all modules. These are sacred territory, set in stone, not to be tampered with or altered in any way!
NIM modules do not have to be only 1 NIM slot wide. Complicated modules with lots of circuitry or with bulky or wide meters, readouts, etc are commonly found that take up 2 or 5 NIM slots. These wider modules, however, must all be a perfect multiple of the standard NIM module width.
Most connectors on the front panel of the modules as well as those on the rear panel, are standard BNC, RF type signal plugs. The standardized impedance of appropriate cables should be 94 ohms, (very weird), but 50 ohms can play unless loading is an issue. This impedance is common to many instrumentation systems.
Some NIM stuff is 94 ohms (whacko), but 75 ohm cabling can be used provided pulse shape fidelity isn't a major issue.
High voltage NIM bias supplies will usually contain and internal polarity "flipper board" that can be turned about to give either plus or minus HV output, as need.
Some NIM modules, especially single channel analyzers and linear amps, often have a 9 pin "D" standard preamp power plug on the rear panel to power an external preamp. This is normally for a PMT or solid state detector. The pinouts on these for power are fairly standardized, but are not rigidly adhered to across the board. Most are wired as follows
+24 VDC pin 7
-24 VDC pin 6
+12 VDC pin 4
-12 VDC pin 9
common return pin 1
You should check the above pinouts to be sure before pluging in a preamp to avoid problems damaging it or the NIM bin supply. ***NOTE********* Some Tennelec preamps and bins are wired for odd ball 9pin hookups.
More, later.......... check back as I add data.....
Update 2020:
What modules should I get?
Wow! I don't know. What are you trying to do?
For fusor work and neutron detection I use a an external preamp (Princeton Gamma Tech) powered off of the NIM bin's 9 pin connector attached directly to my Reuter and Stokes 3He neutron detection tube.
In the bin, I run the preamp output it to a linear amp module (Ortec)
I then run it through a windowed spectroscopy amplifier(Ortec)
Next I feed the spec amp neutron signal to an (Ortec) digital rate meter module.
I used a dead 1 slot NIM module, that I gutted, to build my own custom audio amp and light flasher to see and hear the individual neutron count detections.
I have a 2000 volt bias supply in the bin to bias the 3He tube (Tennelec)
I can't sit here and enumerate every available module that is out there and what they are used for. NIM is now a relic of the past, (1960's era), that has limped to the 21st century. Electronically it is ancient, but it is still a fine source of electronic, plug-and-play "erector set" components for those who can't make their own electronics based on modern age electronic components using knowledge and a soldering iron. In 1998, (22 years ago), when I started, NIM was the cat's PJ's. Today, using the latest electronics, what I have in my big, heavy, 19-inch rack, NIM bin could be placed in a child's small piggy bank including the 2000 volt power supply!
Modules and bins are where you find them. Let the buyer beware on this stuff, as always. The stuff is old and maybe one seller in 100 knows anything about NIM.
I now add a bit more......this is from our longtime member Rich Feldman. I copied his comments and a very valuable URL which should be looked at by all would-be NIM users. Thank you Rich
Just wanted to point out that NIM and "digital" are not mutually exclusive.
There's plenty of digital functionality available in NIM modules, for example timers and counters and coincidence detectors, with NIM and/or mainstream I/O signaling.
I now, 2022 attach a formal pin diagram
Richard Hull