A NEW DESIGN PRINCIPLE FOR NEUTRON SOIL MOISTURE GAGES: THE WALLINGFORD NEUTRON PROBE

THE NEUTRON SCATTERING METHOD FOR MEASURING CHANGES IN SOIL MOISTURE HAS NOW BECOME ACCEPTED AND IS IN WIDESPREAD USE, WITH A VARIETY OF COMMERCIAL EQUIPMENT AVAILABLE. HOWEVER, ALL THE EQUIPMENT HAS, IN GREATER OR LESSER DEGREE, THE DISADVANTAGE OF EXCESSIVE BULK AND WEIGHT; SOME ARE INSUFFICIENTLY ROBUST AND MOST ARE LESS THERMALLY AND ELECTRONICALLY STABLE THAN IS DESIREABLE FOR FIELD USE. IN ORDER TO OVERCOME THESE SHORTCOMINGS, PROVISIONAL SPECIFICATIONS ARE GIVEN FOR A NEW SOIL MOISTURE GAGE. THE BASIC EQUIPMENT CONSISTS OF THE PROBE, TRANSPORT SHIELD, AND CABLE. UNLIKE PREVIOUS DESIGNS, THIS PROBE CONTAINS, IN ADDITION TO THE SOURCE AND DETECTOR, A LARGE PORTION OF THE CIRCUITRY NORMALLY HOUSED IN THE SCALER. THIS GIVES GREAT VERSILITY IN ENABLEING THE PROBE TO BE USED IN CONJUNCTION WITH A WIDE VARIETY OF COMMERCIAL SCALERS AND RATEMETERS. A MINITURE ULTRALIGHTWEIGHT SCALER WITH A DIGITAL COUNT RATE IS UNDER DEVELOPMENT WHERE GREATER PRECISION IS REQUIRED AND WHERE PORTABILITY IS AN IMPORTANT CRITERION. THE MEAN SENSITIVITY OF THE PROBE IS ABOUT 850 CPS PER UNIT MOISTURE VOLUME. THE 16-SECOND COUNTING PERIOD WILL GIVE A RANDOM COUNTING ERROR EQUIVILENT TO NOT MORE THAN 0.10 MOISTURE VOLUME FRACTION WITH 95% PROBABILITY FOR MOISTURES UP TO 0.45 M.V.F. AND 68% PROBABILITY FOR MOISTURES IN EXCESS OF THAT.

  • Supplemental Notes:
    • Vol 108, No 3, PP 160-164, 2 FIG, 1 TAB, 3 REF
  • Corporate Authors:

    N/A

    ,   United States 
  • Authors:
    • Bell, J P
  • Publication Date: 0

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00232742
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Aug 15 2004 2:44AM