Abstract The possible application of Pulsed Fast/Thermal Neutron Analysis (PFTNA) for determining the carbon-to-nitrogen ratio (C/N) of compost will be discussed. This analysis method has several advantages over traditional chemical analysis, including that it is a nondestructive in situ method that does not require extensive sample collection and it analyzes much larger volumes of material (∼1 m3) than traditional chemical analysis (∼1 cm3). The amount of carbon can be determined by irradiating compost with neutrons and measuring the gamma ray peak at an energy of 4.44 MeV that appears due to inelastic scattering. Nitrogen can be determined by measuring the gamma ray peak at 10.83 MeV that appears due to thermal neutron capture. For C/N measurements, a calibration line that relates the C/N mass ratio to the carbon/nitrogen gamma peak ratio should first be constructed; our calibration line was constructed using carbon–ammonium nitrate mixtures. PFTNA measurements were then used to determine carbon and nitrogen peak values in order to utilize the calibration line for calculating the C/N mass ratio. The workability of this methodology has been demonstrated in laboratory experiments. The applicability of PFTNA for compost C/N ratio determinations was evaluated with Monte Carlo computer simulations of neutron propagation in large compost volumes (Geant4 toolkit) and experimental measurements of real compost (volume 1.3 m3). Data from computer simulations and experiments demonstrated that the PFTNA method is fully applicable for determining the C/N ratio in compost material up to values of 25 and even greater.

中文翻译：

---

中子伽马分析在确定堆肥 C/N 比中的应用

摘要 将讨论脉冲快速/热中子分析 (PFTNA) 在确定堆肥的碳氮比 (C/N) 方面的可能应用。与传统化学分析相比，这种分析方法有几个优点，包括它是一种无损原位方法，不需要大量的样品收集，并且它分析的材料体积（约 1 立方米）比传统化学分析（约 1 立方厘米）大得多。碳的量可以通过用中子照射堆肥并测量由于非弹性散射而出现的能量为 4.44 MeV 的伽马射线峰来确定。可以通过测量由于热中子俘获而出现的 10.83 MeV 伽马射线峰来确定氮。对于 C/N 测量，应首先构建将 C/N 质量比与碳/氮 γ 峰比相关联的校准线；我们的校准线是使用碳-硝酸铵混合物构建的。然后使用 PFTNA 测量来确定碳和氮的峰值，以便利用校准线计算 C/N 质量比。该方法的可行性已在实验室实验中得到证明。PFTNA 对堆肥 C/N 比测定的适用性通过蒙特卡罗计算机模拟在大堆肥体积（Geant4 工具包）中的中子传播和实际堆肥（体积 1.3 立方米）的实验测量进行评估。