Scope:

ASTM E385 standard test method uses a 14-MeV neutron activation and direct-counting approach to determine oxygen concentration. Depending on the sample size and available 14- MeV neutron fluence rates, it can also be utilized to determine oxygen concentrations ranging from under 10 μg/g to over 500 mg/g. The 14-MeV neutron activation and direct counting methodology provide a non-destructive, fast, and extremely sensitive method for determining oxygen in a variety of matrices. This test method can also be used for quality and process control in the metals, coal, and petroleum sectors, as well as for research in a variety of fields. 

Test Procedure:

To directly determine mass fractions of oxygen in coal samples for ASTM E385, a fast (14- MeV) neutron activation analysis technique is used. The method was used to evaluate samples of newly developed SRM 1632c trace elements in coal (bituminous). Following six-month storage increments, duplicate samples of each of the SRM’s twelve bottles were measured for each storage condition. Furthermore, each sample was subjected to 10 different analytical runs,  producing a total of 720 measurements per storage term. The oxygen concentration was evaluated by comparing it to primary standard potassium dichromate, and the method’s accuracy was determined by analyzing replication samples of three oxygen-certified reference materials. 

Video 01: Neutron Activation Analysis and Proton induced X-ray Emission

Specimen Size: 

Coal samples of conforming size, shape and macroscopic density are used as test specimens for the ASTM E385. 

Data: 

The data is reported in SI units and is considered standard. ASTM E385 test procedure demonstrated sufficient precision and accuracy to determine a relative change of about 5% or more, in the oxygen mass fraction of about 12%. 

Conclusion: 

ASTM E385 standard test method uses a 14-MeV neutron activation and direct-counting approach to determine oxygen concentration.