Demonstrable diffraction (powder or single-cry still) with the use of zero-power isotopic sources would provide important data on such systems and may have implications in analysis (in this work, we fabricated 100-mCi 55Fe, acceleratorproduced, and 4-mCi 117Pm-Cu beta-excited sources). Powder-diffraction efficiency with the use of a special diffrac to meter adapted to these sources is about 10−5 (calculated) for the Mn Kα X-rays (55Fe) on the NaCl 200 plane. This beam flux at three times natural background intensity was experimentally achieved by using photon spectrometry with proportional counters and multichannel analysis. The Lip diffraction pattern was demonstrated with intensities roughly in agreement with prediction. Lithium fluoride single-crystal diffraction intensity (200 plane) exceeded by 250-fold that of powder. Powder main-peak intensity (θ = 31.5°) produced 9.2 photons per minute at the receiving slit versus 2.3 × 103 events for the single crystal. This single-crystal intensity with 60-sec runs provided a peak resolution of 0.29° full width at half maximum. The first-order Kα, Kβ1 first order, and Kβ1 second-order beams (θ = 31.5°, 28.3°, and 71.6°, respectively) were demonstrated, with 1900 events per minute in the main peak (Kα). X-ray noscreen emulsion was used to study photographic recording on the LiF single crystal with exposures as short as 2.5 hr. A 2-in.-diameter camera, newly designed for the 55Fe source, is collecting further emulsion data.

The isotopic source is stable, highly predictable in intensity, reliable, and compact. Requiring zero power, it thus has a potential for remote applications. Where its low output can be tolerated, it may hold promise for analysis, especially where its size, weight, and stability tire important criteria. Source work here points to possible 55Fe improvement in photon output of 102 over the source described here. Such an increase may make certain special analytical applications feasible.