ASTM_D_6727_-_01_2007.pdf

Designation:D672701(Reapproved 2007)Standard Guide forConducting Borehole Geophysical LoggingNeutron1This standard is issued under the fixed designation D6727;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This guide is focused on the general procedures neces-sary to conduct neutron or neutron porosity(hereafter referredto as neutron)logging of boreholes,wells,access tubes,caissons,or shafts(hereafter referred to as boreholes)ascommonly applied to geologic,engineering,groundwater andenvironmental(hereafter referred to as geotechnical)investi-gations.Neutron soil moisture measurements made usingneutron moisture gauges,are excluded.Neutron logging forminerals or petroleum applications is excluded,along withneutron activation logs where gamma spectral detectors areused to characterize the induced gamma activity of mineralsexposed to neutron radiation.1.2 This guide defines a neutron log as a record of the rateat which thermal and epithermal neutrons are scattered back toone or more detectors located on a probe adjacent to a neutronsource.1.2.1 Induction logs are treated quantitatively and should beinterpreted with other logs and data whenever possible.1.2.2 Neutron logs are commonly used to:(1)delineatelithology,and(2)indicate the water-filled porosity of forma-tions(see Fig.1).1.3 This guide is restricted to neutron logging with nuclearcounters consisting of scintillation detectors(crystals coupledwith photomultiplier tubes),or to He3-tube detectors with orwithout Cd foil covers or coatings to exclude thermalizedneutrons.1.4 This guide provides an overview of neutron loggingincluding:(1)general procedures;(2)specific documentation;(3)calibration and standardization,and(4)log quality andinterpretation.1.5 To obtain additional information on neutron logs seeReferences section in this guide.1.6 This guide is to be used in conjunction with StandardGuide D5753.1.7 This guide offers an organized collection of informationor a series of options and does not recommend a specific courseof action.This guide should not be used as a sole criterion forneutron logging and does not replace education,experience,and professional judgment.Neutron logging procedures shouldbe adapted to meet the needs of a range of applications andstated in general terms so that flexibility or innovation are notsuppressed.Not all aspects of this guide may be applicable inall circumstances.This ASTM standard is not intended torepresent or replace the standard of care by which the adequacyof a given professional service must be judged withoutconsideration of a projects many unique aspects.The wordstandard in the title of this document means that the documenthas been approved through the ASTM consensus process.1.8 The geotechnical industry uses English or SI units.Theneutron log is typically recorded in units of counts per second(cps)or in percent porosity.1.9 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory requirements prior to use.The use ofradioactive sources in neutron logging introduces significantsafety issues related to the transportation and handling ofneutron sources,and in procedures to insure that sources arenot lost or damaged during logging.There are differentrestrictions on the use of radioactive sources in logging indifferent states,and the Nuclear Regulatory Agency(NRC)maintains strict rules and regulations for the licensing ofpersonnel authorized to conduct nuclear source logging.2.Referenced Documents2.1 ASTM Standards:2D420 Guide to Site Characterization for Engineering Designand Construction Purposes(Withdrawn 2011)3D653 Terminology Relating to Soil,Rock,and ContainedFluids1This guide is under the jurisdiction ofASTM Committee D18 on Soil and Rockand is the direct responsibility of Subcommittee D18.01 on Surface and SubsurfaceCharacterization.Current edition approved July 1,2007.Published August 2007.Originallyapproved in 2001.Last previous edition approved in 2001 as D6727 01.DOI:10.1520/D6727-01R07.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 D5088 Practice for Decontamination of Field EquipmentUsed at Waste SitesD5608 Practices for Decontamination of Field EquipmentUsed at Low Level Radioactive Was