This page explains connectors commonly used in the nuclear industry and why you'd want to use one vs the other.


Early equipment (ie NIM bins) primarily use BNC. Later equipment still uses BNC but some equipment (notably CAMAC) uses Lemo 00 connectors. Lemo connectors are much more expensive than BNC but are more compact and should provide a snugger fit.



Nuclear Instrumentation Model (NIM) backplanes primarily focus on analog signals. The crate (chassis + power supply) provides some interconnect but primarily provides power and cooling. Instead, signasl are primarily patched through BNC connectors on the front of the module.

NIM's can use either TTL or ECL logic. My understanding is that generally TTL is less expensive but ECL is faster.


CAMAC focuses on digital electronics and computer control. It introduces a communications bus with a bus controller in the rightmost slot. The bus controller can be a standalone unit or provide PC connectivity through GPIB, RS-232, etc.

CAMAC primarily uses LEMO 00 connectors with occasional BNCs.


Ludlum pictures

Above: from left to right: C, SHV, BNC. Note extended insulation on SHV rear

Common connectors:

Image Name Volt Amp Diameter Weatherproof Cost Misc
BNC 500 N Low
MHV 5000 N
SHV 5000 N Long ground sheath ensures center disconnects before ground
UHF 500
C 1500 Larger Y


  • Ref cost: lowest cost bulkhead I could find at a quick search (2015-12). Primarily eBay

JM general reccomendations:

  • Use BNC for low voltage probes (ex: GM tubes)
  • Use SHV for high voltage probes (ex: He-3 tubes)
  • Consider C if you need weatherproofing
  • For 5-40 kV you can get some reasonably priced/sized connectors
  • >40kV:
    • Do you really need a (bulky/expensive) connector? Consider simple terminals
    • If you insist, use x-ray connectors




    • CA1 is the cylindrical three prong type
    • CA22 is the booted type that I see sometimes
    • Classifies the Federal Standard as a medical connector and the conical as an industrial standard

Federal standard

Most common type I see. Three pin is most common, but also seen more (ex: on SEM). Retention / clamping ring style also seems to vary.

Claymount CA1

Comprehensive GE chart

Sample equipment using this:

  • Eureka
  • GE


Claymount CA22


C connector

Primarily used on Ludlum detectors/meters.

  • Doesn't have much info
  • Indicates that white vs red center is 50 vs 75 ohm although doesn't say which is which
  • I have only seen white centers

  • 50 ohm (white)
    • 75 ohm below 300 MHz
  • 1500 volts peak, std
  • 3000 VRMS
  • Usually weatherproof

Notes from 2015-12

Found connectors under the following names. I haven't looked to formally figure out the differences

R390, R-390A


  • Bulkhead w/ 4 bolts
  • Ex: Amphenol 082-504: UG-568/U, C-Type Straight Solder Jack, Panel Mount, 50 Ohm


  • Ex: Apnhenol 082-532: RF Connector, UG-628A/U, C-Type Straight Clamp Plug for RG-8, RG-9, RG-213, RG-225, 50 Ohm


  • Ex: Amphenol 082-515: RF Connector, UG-634/U, C-Type Straight Solder Jack, High-Voltage, Bulkhead, 50 Ohm


  • Bulkhead?


  • Bulkhead barrel

connectivity.txt · Last modified: 2016/09/28 03:45 by mcmaster
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