Field Testing a Mobile Inelastic Neutron Scattering System to Measure Soil Carbon

Yakubova, Galina; Wielopolski, Lucian; Kavetskiy, Aleksandr; Torbert, H. Allen

doi:10.1097/ss.0000000000000099

Cited by 15 publications

(21 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The parameters ( a , b , and c ) in this equation varied from site to site (Yakubova et al, 2014). Thus, selecting the parameter that characterizes carbon content at some site and connection with an INS γ signal by direct proportional dependence can be ambiguous.…”

Section: Methodsmentioning

confidence: 99%

Benchmarking the Inelastic Neutron Scattering Soil Carbon Method

Yakubova

Kavetskiy

Torbert

2015

Vadose Zone Journal

Self Cite

View full text Add to dashboard Cite

The herein described inelastic neutron scattering (INS) method of measuring soil carbon was based on a new procedure for extracting the net carbon signal (NCS) from the measured γ spectra and determination of the average carbon weight percent in the upper ∼8‐cm soil layer (AvgCw%8). The NCS extraction utilized the net‐INS spectrum, which was the difference between the INS and thermal neutron capture (TNC) spectra and the net‐INS system background spectrum. The proportionality between NCS and AvgCw%8 for any shape of soil carbon depth distribution was demonstrated theoretically. The theoretical model for NCS calculations accounted for carbon depth distribution and neutron and γ ray propagation laws in our analysis; previous model results were verified by comparison with a Monte Carlo simulation using Geant4. The experimental results confirmed the identified proportionality. The mobile INS system was calibrated using pits filled with synthetic soil; this calibration was used for AvgCw%8 determinations in INS field measurements. The AvgCw%8 was also determined by the dry combustion method. Benchmarking the soil carbon determination by INS demonstrated results that coincided with dry combustion technique (DCT) results (within experimental error limits). Given the agreement between these methods, the described INS measurement system can be recommended as a reliable alternative means for measuring soil carbon.

show abstract

Section: Methodsmentioning

confidence: 99%

Benchmarking the Inelastic Neutron Scattering Soil Carbon Method

Yakubova

Kavetskiy

Torbert

2015

Vadose Zone Journal

Self Cite

View full text Add to dashboard Cite

show abstract

“…The distribution of soil carbon with depth is usually nonuniform (i.e., carbon level decreases as depth increases) and by first approximation can be described by exponential law [15]. The parameters of these distributions vary from site to site [56]. For this reason, correlations between the carbon peak intensity in the gamma spectrum and characterization of soil carbon content parameters are not obvious.…”

Section: Parameter Selection For Soil Carbon Characterizationmentioning

confidence: 99%

“…As previously described [56], our PFTNA system was mounted on a platform that could be transported by tractors or all-terrain vehicles over various field terrains. The dimensions of our mobile platform were 75 cm · 23 cm · 95 cm and weighs~300 kg.…”

Section: Mobile System For Soil Carbon Determinationmentioning

confidence: 99%

“…The time dependence of the thermal neutron number n th (t) can be estimated as: Figure 5. Raw experimental soil gamma spectra [56]. where τ th is the lifetime of thermal neutrons.…”

Section: Extracting the "Net Ins Spectra"mentioning

confidence: 99%

“…A custom-made electronic scheme and data acquisition software could be used in some cases due to the absence of suitable standard equipment (e.g., NaI(Tl) detector with corresponding electronics and ProSpect v0.1.11-vega software from XIA LLC, Hayward, CA; see Ref. [56]). …”

Section: Operational Electronics and Data Acquisition Softwarementioning

confidence: 99%

See 2 more Smart Citations

Neutron-Stimulated Gamma Ray Analysis of Soil

Kavetskiy¹,

Yakubova²,

Torbert³

2017

New Insights on Gamma Rays

Self Cite

View full text Add to dashboard Cite

This chapter describes technical aspects of neutron-stimulated gamma ray analysis of soil carbon. The introduction covers general principles, different modifications of neutron-gamma analysis, measurement system configuration, and advantages of this method for soil carbon analysis. Problems with neutron-gamma technology in soil carbon analysis and methods of investigations including Monte-Carlo simulation of neutron interaction with soil elements are discussed further. Based on the investigation results, a method of extracting the "soil carbon net peak" from the raw acquired data was developed. The direct proportional dependency between the carbon net peak area and average carbon weight percent in the upper 10 cm soil layer for any carbon depth profile was shown. Calibration of the measurement system using sand-carbon pits and field measurements of soil carbon are described. Measurement results compared to chemical analysis (dry combustion) data demonstrated good agreement between the two methods. Thus, neutron-stimulated gamma ray analysis can be used for in situ determination of near-surface soil carbon content and is applicable for precision geospatial mapping of soil carbon.

show abstract