| Abstract: | The fast- and thermal-neutron fluence rates from a 3.7 ??g 252Cf neutron source in a simulated borehole have been measured as a function of the source-to-detector distance using air, water, coal, iron ore-concrete mix, and dry sand as borehole media. Gamma-ray intensity measurements were made for specific spectral lines at low and high energies for the same range of source-to-detector distances in the iron ore-concrete mix and in coal. Integral gamma-ray counts across the entire spectrum were also made at each source-to-detector distance. From these data, the specific neutron-damage rate, and the critical count-rate criteria, we show that in an iron ore-concrete mix (low hydrogen concentration), 252Cf neutron sources of 2-40 ??g are suitable. The source size required for optimum gamma-ray sensitivity depends on the energy of the gamma ray being measured. In a hydrogeneous medium such as coal, similar measurements were made. The results show that sources from 2 to 20 ??g are suitable to obtain the highest gamma-ray sensitivity, again depending on the energy of the gamma ray being measured. In a hydrogeneous medium, significant improvement in sensitivity can be achieved by using faster electronics; in iron ore, it cannot. ?? 1979 North-Holland Publishing Co. |
| Genre: | Article |
| ProdID: | 70012517 |
| Citation Author: | Senftle, F. E.; Macy, R. J.; Mikesell, J. L. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 302 |
| Citation Issue: | C |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Nuclear Instruments and Methods |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 10 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | Elsevier |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Determination of the optimum-size californium-252 neutron source for borehole capture gamma-ray analysis; 1979; Article; Journal; Nuclear Instruments and Methods; Senftle, F. E.; Macy, R. J.; Mikesell, J. L. |
| Citation Start Page: | 293 |
| Citation Volume: | 158 |
| Citation Year: | 1979 |
| Type: | citation/reference |
| Text: | Determination of the optimum-size californium-252 neutron source for borehole capture gamma-ray analysis; 1979; Article; Journal; Nuclear Instruments and Methods; Senftle, F. E.; Macy, R. J.; Mikesell, J. L. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1016/S0029-554X(79)92890-8 |
| Date Other: | Mon, 1 Jan 1979 00:00 -0600 |
| Publisher: | Elsevier |
