The paper reports some new results on irradiation characteristics of synthetic quartz crystals and their application to radiation hardening. The present results show how the frequency shift in quartz crystals can be influenced by heat processing prior to irradiation and how this procedure can lead to radiation hardening for obtaining precise frequencies and time intervals from quartz oscillators in space.In line with the thinking already proposed (H.Bahadur and R. Parshad, Proc. 12th PTTI Conference, pp.829- 849, 1980) for explaining some of the irradiation characteristjcs of natural crystals, for the present work, it was assumed that the positive frequency shift in irradiated synthetic crystals is due to crystal imperfections. The crystal imperfections in synthetic crystals were sought to be removed by appropriate annealing (slcw heating to 240°C followed by s l~w cooling). Different annealed crystals on irradiation gave either a negative frequency shift, thus simulating the behavior of natural crystals or almost a zero frequency shift. This result woula be due to the positive frequency contribution of remanant crystal defect^ matching the negative frequency contribution of the A-centers of the crystal lattice.The experimental results indicate a new way of radiation hardening.This work was supported in part by a Homi Bhabha Fellowship awarded to H. Bahadur.
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