Paper presented (oral presentation) at the 34th Conference of European Group for Atomic spectroscopy (34thEGAS), 9-12 July 2002, Institute of Solid State Physics, Bulgarian Academy of Sciences, 1784 Sofia, Bulgaria, Europhysics Conference Abstarcts, published by European Physical Society (EPS), Ed: K.Blagoev, abstract no: F2-4, page 103.
ROOM TEMPERATURE ATOMIC SPECTRA FROM SOLID
RADIOISOTOPES AND XRF SOURCES
M.A.Padmanabha Rao
The author has newly detected light emission from radioisotopes such as 57 Co, 60 Co, 90 Sr, 131 I, 133 Ba, and 137 Cs, present as radiochemicals [1-3]. Even when 57 Co and 60 Co were present as cobalt metal the light emission was detected, while incandescent light was only known so far from metals. The emission also was detected from solid Rb, Ba and Tb XRF sources (AMC 2084,U.K.), which are Rubidium Sulphate, Barium oxide and Terbium peroxide salts under g -excitation. Notably, it was also detected from Cu, Mo, and Ag XRF sources (AMC 2084) present as Cu, Mo, and Ag metals respectively at room temperature [1-3]. These sources emit feeble light emission that cannot be seen by naked eye. However, placing source directly over a photo multiplier tube (9635QB, THORN EMI) facilitated detection of its light emission. The light emission observed commonly from all the radiochemicals tested including 90 Sr and 57 Co could not be attributed to either luminescence or scintillation as these chemicals do not pertain to the class of luminescent or scintillation materials. Likewise, the emission detected at room temperature from 57 Co, and 60 Co or Cu, Mo, and Ag XRF sources present as metals could not be attributed to luminescence, scintillations, Cherenkov light or incandescence for metals being opaque to light, and seems to be a surface phenomenon.
On the other hand there are various reasons in support of the hypothesis that radioisotopes and XRF sources emit fluorescent light. For example, since the X-, gamma , and beta radiations are atomic emissions, strong possibility exists for them to cause light emission within the same excited atoms of their origin [1-3]. Atomic spectrometers were of no avail to verify atomic spectra from these sources because of feeble light emission. However, a pair of plastic sheet polarizers aided in understanding the nature of spectra from radioisotopes and XRF sources [2]. Characteristics of these polarizers were such that they do not transmit UV radiation up to 400 nm. Parallel pair transmits visible light (VIS) but polarized from 410-710 nm, and near infrared (NIR) radiation beyond 710 nm. Crossed pair transmits only the near infrared radiation beyond 710 nm. (a) On keeping source over the PMT, the counts noted represented entire optical spectrum (UV, VIS, and NIR radiations). (b) On introducing parallel pair of polarizers between source and the PMT, they transmitted only the VIS and NIR radiations from the source to the PMT. (c) The crossed pair (on rotating one of the polarizers to 90 ° ) transmitted only the NIR radiation. Reduction in counts noticed by mere rotation of a polarizer confirmed VIS emission. In these three readings the counts due to X-, gamma, and beta radiations are included. (d) In order to estimate these counts, a thin 0.26 mm thin black polyethylene sheet was introduced below the polarizers to exclude NIR radiation but to transmit these radiations to the PMT. The difference in counts between steps a-b, b-c, and c-d offered the contributions of UV (up to 400 nm), VIS (400 - 710 nm), and NIR (beyond 710 nm) radiations in the over all light intensity noted in step a. These estimates showed that in general radioisotopes and XRF sources emit mostly UV radiation though a fraction of their optical emission lies in VIS and NIR range. A comparison of spectra of low and high energy sources showed a significant fall in UV contribution and a corresponding raise in that of VIS and NIR was noticed from high energy sources like 60 Co in comparison to that of 57 Co. The same was noticed between 86 Rb and Rb XRF source; 90 Sr and 147 Pm; and 60 Co and 241 Am. Moreover, the author preliminarily studied optical spectra of some of these sources using narrow band filters. The study showed agreement of certain peak positions with strong lines in conventional atomic spectra, for example between certain peak positions observed from Rb XRF source and strong lines of Rb II atoms . Interestingly, the study suggests that in the case of atomic spectrum from an ionizing source the positions of strong lines depend upon the ionizing radiation energy. Light emission newly observed following X-rays from XRF sources finds immediate application in black hole physics.
[1] M.A.Padmanabha Rao, X-ray source emits not only X-rays but also low energy electromagnetic radiation, 1998 Symposium on Radiation Measurements and Applications, (Ninth in a Series), May 11-14,1998, College of Engineering, The University of Michigan, Ann Arbor, abstract 3PW26 in Volume of abstracts (1998). https://www.angelfire.com/sc3/1010/michigan1998.html
[2]
M.A.Padmanabha Rao,
Possible biological effects of UV radiation newly
detected from
radioisotopes, in Proceedings
of the Symposium on Low Level Electromagnetic Phenomena in Biological Systems
(BIOSYS-’99), 1999, School of Environmental Sciences, Jawaharlal Nehru
University, New Delhi-110067, India, edited
by Jitendra Behari, and Editors of
Indian Journal of Biochemistry & Biophysics, (Printed at National
Institute of Science Communication, Pusa Road, New Delhi -110012) p.68. https://www.angelfire.com/sc3/1010/ uvdosimetry.html
[3 ] M.A.Padmanabha Rao, Discovery of light emission from XRF sources, M.A. Padmanabha Rao. Presented in 50th Annual Denver Conference, Steamboat Springs, Colorado State, U.S.A., 2001, Sponsored by the International Centre for Diffraction Data, Newtown Square, Philadelphia,U.S.A, Abstract F-01, p.124. www.dxcicdd.com/01/pdf/F-01.pdf
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