JM: have assortment of bare tubes. Notably, my Ludlum 15 also has one as the alpha probe

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“all end-window LND probes are known to violently vaporize themselves into oblivion if overvolted(including spikes)”

Specifications

Source

  • Recommended anode resistor (meg ohm): 1
  • Maximum starting voltage (volts): 800
  • Recommended operating voltage (volts): 900
  • Operating voltage range (volts): 850
  • Maximum plateau slope (%/100 volts): 10
  • Minimum dead time (micro sec): 150
  • Gamma sensitivity Co60 (cps/mr/hr): 40
  • Tube capacitance (pf): 3
  • Weight (grams): 150
  • Maximum background shielded 50mm Pb + 3mm Al (cpm): 50

Socket

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# Size Function Note
1 L N/C
2 S V+ 1M resistor to center
3 S N/C
4 L Ground

Units

Case vendor Case model Tube vendor Tube model Works? Notes
XETEX LND 723 86-36 No Outgassed before I got it
XETEX LND 723 86-36 Yes? looks okay but untested
LND 723 88-13 No M15 original tube. Outgassed during calibration
TGM No accidentally popped
TGM? Yes into M15?

LND unit

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Sample label:

LND, INC.
723
MADE IN USA
86-36

Ludlum 44-7 unit

From Ludlum M15 system

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Original socket badly corroded. Repaired socket with cleaning + solder dip. However, ultimately the tube also had to be replaced

1M resistor in series on center + pin

Original tube degradation:

  • Worked after cleaning
  • Shipped to Ludlum for service
  • Ludlum reported the tube wasn't reporting correctly
  • Shipped back to me
  • Tube unresponsive. Vacuum window noted no longer taught

XETEX unit

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These have some sort of support electronics, leading to a 4 wire CMC connector instead of a typical coaxial connector

Sample data plate:

MADE IN USA
SERIAL NO. 020969
XETEX, INC.
Mountain View, CA

Other unit is S/N 020967

TGM unit

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Looks identical to my 723 88-13, so assuming its LND

Data plate:

TGM DETECTORS INC.
34 Bear Hill Road
WALTHAM, MA 02154
N210 S/N 3585

References

 
lnd/723.txt · Last modified: 2016/10/26 11:39 by mcmaster
 
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