Proceedings of the Symposium on Low level Electromagnetic Phenomena in Biological Systems, 3 & 4 February 1999, School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, Edited by Jitendra Behari, and Editors of Indian Journal of Biochemistry and Biophysics, (printed at National Institute of Science Communication, New Delhi -110012,  pp 68-72,


M. A . Padmanabha Rao

114 Charak Sadan, Vikaspuri, New Delhi 110018, India,

Notably from radioisotopes as well as characteristic X-ray sources the author reported to have discovered light emission predominant in ultraviolet (UV) radiation1-4. Since it is not known earlier that UV radiation associates with ionising radiations in causing biological effects when radioisotopes such as 99mTc, 131I, 201Tl are internally administered into the body, the biological effects and conventional dose estimates to the bodily organs deserve a thorough review.


Henry Becquerel discovered radioactivity in 1896 from the naturally occurring phosphorescent potassium uranyl sulphate.5. Similarly radium (present as chloride) discovered from the uranium ore, pitchblende by Pierre and Marie Curie in 1898 has also been a radioactive and feeble self-luminescent material6. Then came the artificially produced radioisotopes discovered on alpha irradiation by Irene Curie and Fredric Joliot in 1933 followed by neutron irradiated and cyclotron produced radioisotopes. But their emission of any phosphorescence or fluorescence was neither reported nor predicated by earlier researchers. In these circumstances, from all the radioisotopes investigated the author discovered incredibly very poor fluorescent light emission, which is neither visible to the naked eye nor can be explained by any known phenomenon1-4. 

Radioisotope and X-ray sources are examples of an immensely important family of ionising radiation sources, yet a big distinction persists between the two. However light emission has also been discovered from X-ray sources, say along with Cu, Rb, Mo, Ag, Ba, or Tb X-rays from Cu (metal), rubidium sulphate, Mo (metal), Ag (metal), barium oxide, or terbium peroxide respectively on gamma excitation from 241Am [AMC 2084, Amersham International, UK.]. Earlier to this, no literature is available on light emission either from an X-ray tube or characteristic source ever since the discoveries of X-rays (bremsstrahlung) from Crook’s tube by W.C. Roentgen and characteristic X-rays of elements by Charles Glover Barkla. The light observed as a common emission from both X-ray and radioisotope sources led to a fundamental finding that light photons follow X-, gamma rays, and beta particles from one and the same excited atom that can have a great significance in atomic and nuclear sciences. For example, within 131I atom its beta, gamma, and Xe X-ray emissions independently produce room-temperature fluorescent light photons. Also has been found, from all the radioisotopes tested, a complete range of optical spectrum including ultraviolet (UV), visible (VIS), and near infrared (NIR) radiations. Since most of their light emission lies in UV range [up to 400 nm], which causes biological effects the insight is noteworthy to radiobiologists.           

Most interestingly, from 131I and 137Cs the light protons were found exceeding gamma ray photons when counted by a high gain photo multiplier tube (9635QB, THORN EMI) and a scintillation detector respectively. In clear words, they have been found as good light and UV emitters over other radioisotopes tested. 131I accumulates mainly in the thyroid gland, but does even in total body, gastrointestinal tract and lungs due to diagnostic and therapeutic procedures or accidental exposure7-9. Most importantly, the new insight on UV radiation emission challenges the radiation dose estimates which relied only on beta particles, gamma, and Xe X-ray and conversion electron emissions10-13. Unfortunately, the current wisdom on biological effects of UV radiation is limited to external exposure, for example, proteins inducing free radicals, gene activation, haemolysis, skin cancers, and effect in intact eye lens14. It is the hope that the new insight would prompt the readers to investigate whether UV radiation is responsible in causing any biological damage to the cells unknown so far when associated with ionising radiations. The author speculates that the cells and bodily organs would also be exposed to different energies by a new atomic phenomenon termed Rao (Padmanabha Rao) effect1-4. The author postulated that when ionizing radiation passes through charged space around a core electron causes low energy electromagnetic radiation with energy higher than that of UV radiation in eV level termed ‘Bharat radiation’. Also postulated that it in turn excites valence electron and causes fluorescent light emission4.  To sum up, ionizing radiation, Bharat radiation and fluorescent light follow one after another from one and the same radioactive atom. Currently no detector is available to detect the Bharat radiation. Since the intensity of light from any radioisotope depends upon the type and energy of ionizing radiations, cellular exposures to optical radiation differ from one radioisotope to the other for the same activity level. Anyhow, the purpose of this paper is to prompt the readers to probe further on the biological effects, if any caused by the Bharat radiation emission.           


In the current study, a PMT coupled to a ‘preamplifier served uniquely as a sensor not only to the light but also beta particles15, X-rays and gamma rays, on connecting through a linear amplifier to an 8K MCA. The PMT was housed in a metal casing with a lid. And prior to the opening of the lid for replacing a source with another, terminated high voltage supply to the PMT. Also the experiment was conducted in dark room to prevent the PMT from possible light leak, if any. For each photon or particle detected the PMT sends a single photocathode pulse. Eventually the MCA displays pulse height spectrum devoid of any peaks for the radiation intensity that the PMT detected. Therefore, integral counts were noted for 4 min. and shown in Table 1 in terms of counts sec-1 (cps). Gain of the linear amplifier had to be set higher than what is usually required for a Gamma or Beta Spectrometer, and the time constant at 0.1 m sec. Radioisotopes were procured from the Board of Radiation and Isotope Technology, Mumbai. Thin Mylar film fixed in front of the radioisotopes had to be removed to permit light transmission.

          Use of a pair of sheet polarizers of the type described by Robertson16 not only confirmed the said light emission also facilitated in estimating the contributions of UV, VIS, and NIR radiations. On keeping the pair in a beam of UV-radiation, they showed opacity (fig.1). In a beam of visible (VIS) light, they transmitted a low percent of incident light, which has been plane polarized in the visible range from 400-710 nm, and near infrared (NIR) radiation which began to increase rapidly from nearly 710 nm onwards. On rotating one of the sheets to 90° (crossed pair), the amount of light transmitted in the near infrared region has been just about the same as when the two plates were parallel while the second sheet behind eliminated the polarized visible light transmitted by the first sheet (fig.1).

Fig.1. In a beam of visible (VIS) light, they transmitted a low percent of incident light, which has been plane polarised light in the visible range from 400-710 nm, and near infrared (NIR) radiation which began to increase rapidly from nearly 710 nm onwards. On rotating one of the sheets to 90° (crossed pair), the amount of light transmitted in the near infrared region has been just about the same as when the two plates were parallel while the second sheet behind eliminated the polarised visible light transmitted by the first sheet.                  


The following method developed by the author served commonly for all the sources. 137Cs (137mBa) exemplifies a source with three types of ionizing radiations (IRs) namely beta particles, gamma rays, as well as Ba X-rays. Step (a): On keeping the source directly over quartz window of the PMT, 9098 ± 6.2 cps have been observed. These counts were attributed due to light as well as IRS that were detected. Step (b): A pair of sheet polarizers in parallel position were interposed between the source and the PMT. Fig.1 shows that these sheets do not allow transmission of UV radiation to PMT, but allow visible (VIS) light which is polarized, NIR and IRs that caused 793 ± 3.6 cps. Therefore the difference in counts, 8305 ± 5.0 cps estimated from steps (a-b) was attributed to the UV radiation detected. Step (c): On rotating one of the sheets to 90°  (crossed pair), the sheets do not transmit visible (polarized) light but transmit only the NIR and IRs, which caused 720 ± 3.5 cps. Notably, the fall of counts noticed by mere rotation of a sheet due to elimination of visible light confirms emission of visible light.  The difference in counts 73 ± 2.9 (Table 1) are thus due to visible (VIS) light emission. Step (d): A 0.26 mm thin black polyethylene sheet was introduced between sheets and the PMT to exclude even NIR radiation, but to allow IRs that caused 519 ± 2.9 cps. The difference in counts, 201 ± 2.3 cps (Table 1) by steps (c-d) are thus due to NIR radiation. 

Fig.2. A schematic diagram of the experimental set up used for confirmation of light emission and measurement of ultraviolet [UV], visible [VIS] and near infrared [NIR] radiations observed along with ionizing radiations (IRs) from 137Cs. Photo multiplier tube served as sensor to both light and IRs. 

Similarly from the rest of the sources listed in Table 1 including the internally administered radioisotopes like 99mTc, 131I and 201Tl, the contribution of UV radiation ranks very high, while low for the visible and very low for the near infrared radiations. Accurate methods can follow on estimation of UV intensities for the same activity level from the desired internally administered radioisotopes.  To conclude that this new insight study may prompt the readers to review the biological effects and radiation dose estimates in internal dosimetry.

 Table1. Intensities of ultraviolet (UV), visible (VIS), and near infrared (NIR) radiations and light (UV+VIS+NIR radiations) measured from each radioisotope source in terms of counts per sec (cps), using photo multiplier tube (9635QB, THORN EMI) as sensor .201TI, 131I, and 99mTc are important internally administrated radioisotopes.



 Net counts  











Near infrared





Mn X-rays

133 ±  1

125 ±  1


Cs X,  γ

3,239 ±  4

2,803±  4

2,733 ± 8

41 ±  2

29 ±  2


Gd X,

Sm X,β, γ

4,072 ±  4

3,052±   6

2,757 ± 13

180 ±  3

115 ±  3


Hg X,γ

1,860  ± 3

1,830 ±  3

1,752 ±   4

70 ±  1

8 ±  0.4



3,623 ±  4

3,606 ±   4

3,583 ±  5

21 ±  1

2 ±  0.4


β, γ

2,338 ±  3

2,333 ±  3

2,234  ±  4

98 ±  1

1 ±  0.4


Pr X,β, γ

755 ±  1

727 ±  1

718 ±  1

8 ±  0.3

1 ±  0.2


Ba X,β, γ

9,098 ±   6

8,579 ±  7

8305 ± 5

73 ±  3

201 ±  2


Xe X,β, γ

241,948 ± 4

234,079 ± 5

226,209 ± 2

7,553 ± 4

317 ±  2


Hg X,β

109,958 ± 21

84,984 ± 24

82,097 ± 29

2,517 ± 4

370 ±  2


β, γ

77,606 ± 18

38,677 ±  22

28,453 ± 52

3,798 ± 16

6,426 ± 13

90Sr +90Y

β, γ

55,504 ± 15

29,563  ± 18

24,643 ± 44

2,372 ± 14

2,548 ± 11


Np Lx, γ, alpha

1,696 ±  3

1,678 ±  2

1,645 ±  3

32 ± 0.6

1.1 ± 0.5


Fe X, γ

7,773 ±  6

5,600 ±  7

4,464 ± 16

749 ±  5

387 ±  5


Fe X, γ

690 ±  2

626 ±  2

601 ±  4

11 ±  1.0

14 ±  0.8


Tc X, γ

487 ± 3

468 ±  5

440  ± 7

18 ±  0.5

10 ± 2.2


In X, γ

106,491 ± 21

91,105 ± 23

88,325 ±  33

2,012 ± 6

768 ±  4


β+, NeX, γ

2,550 ±  3

2,284  ± 4

2,168 ±  8

57 ±  3

59 ±  2


β, γ

117,028 ± 20

48,393 ±  28

42,618 ± 76

2,110 ±  27

3,665 ± 22


β, γ

47,200 ± 14

39,985 ±16

38,376 ± 38

609 ±  12

1000 ±  10


β, γ

2,971 ±  4

2,207 ±  3

2,052 ±  9

51 ±   3

104 ±  2


β, γ

151,735 ± 25

30,123 ±  34

Characteristic X-ray sources in AMC 2084:

Cu metal

Cu X-rays

80 ±  1

22 ±  1

Rb salt

Rb X-rays

125,381 ± 23

125,321± 23

124.845 ± 27

463 ±  3

13 ±  1

Mo metal

Mo X-rays

95  ±  1

27 ±  1

Ag metal

Ag X-rays

111 ±  1

30±  1

Ba salt

Ba X-rays

2,167 ± 3

2,064 ±  7

1,974 ± 13

79 ±  3

11 ±   3

Tb salt

Tb X-rays

154 ± 1

37 ±  1


The counts given here are corrected for background level (13 cps) of the photo multiplier. Cu, Rb, Mo, Ag, Ba, and Tb targets (AMC 2084) are Cu, Rb, Mo, Ba and Tb XRF sources. Cu, Mo and Ag targets; 57Co* and 60Co* showed light emission notably at room temperature though in metal form.


The author gratefully acknowledges the kind assistance of Dinesh Bohra and Arvind Parihar for conducting experiments initially concerning this work. The experimental work was done at the Defence Laboratory, Jodhpur, 342001, India, where the author worked formerly as Deputy Director.


1      M A Padmanabha Rao, (1997) Atomic emission of light from sources of ionizing radiation by a new phenomenon, Technical Report No: DLJ/ IL/ 97/ 7 of the Defence Laboratory (Defence Research and Development Organization), Jodhpur 342011, Rajasthan, India, April 1997).

2       M A Padmanabha Rao, (1997) Light emission observed from ionizing radiation sources by an atomic phenomenon, Paper presented at the National Symposium on Contemporary Physics: Some Aspects, Organized by the Indian Physics Association, Physics Department, Presidency College, Kolkata, India, November 6-8, page 25.

3      M A Padmanabha Rao, (1998) Radioisotopes and X-ray sources emit fluorescent light by an atomic phenomenon, Proceedings of the 12th National Symposium on Radiation Physics, (eds. P K  Bhatnagar and A.S.Pradhan), Sponsored by Indian Society for Radiation Physics, Defence Laboratory, Jodhpur 342011, India, pp 273-276, and January 28-30 (Publisher: Hindustan Enterprises, Jodhpur 342003, Rajasthan, India).

4      M. A Padmanabha Rao, (1998) X-ray source emits not only X-rays but also low energy electromagnetic radiation, Paper presented at the 1998 Symposium on Radiation Measurements and Applications (ninth in a series), Sponsored by College of Engineering and others, The University of Michigan, Ann Arbor, May 11-14 [abstract: 3PW26].

5       Becquerel H. (1896) Sur les radiations invisible emises par les corps phosphorescents, Competes rendus de l’Academie des sciences, Paris 122, 501-503,1896 (translation) In G T  Seaburg and W  Loveland (Eds) Nuclear Chemistry, Benchmark Papers in Physical Chemistry and Chemical Physics V.5, Hutchinson Ross Publishing Company, Pennsylvania, pp. 23-25. 

6       R L  Wolke (1988), J.Chem.65, 561

7      L K  Bustard, D.H. Wood, E E Elefson, H A Ragan and R O McClelian (1963) 131I in milk and thyroid of dairy cattle following a single contamination event and prolonged daily administration, Health Physics, 9, 1231.

8      Radiological Health Handbook (1970) Bureau of Radiological Health, US Department of Health Education, and Welfare, Rockville, Maryland 20852.

9      M Eisenbud (1987) Environmental Radioactivity, Academic Press, Orlando.

10     Limits for intakes of radio-nuclides for workers (1978), International Commission on  Radiological Protection publication 30, Part I.

11     Sources and effects of ionizing radiation, Report to General assembly with annexes (1993) UNSCEAR Report.

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16   J K  Robertson, (1961) Introduction to optics, Geometrical and Physical (D.Van Nostrand  Company inc, Toronto, pp 259-270.


         (Cited this paper in the Report of the Seventh meeting of the Ozone Research Managers of the Parties to the Vienna Convention for the Protection of the Ozone Layer, the World Meteorological Organization (WMO), Geneva, 18 to 21 May 2008 (organized by the Ozone Secretariat of the United Nations Environment Programme (UNEP) together with the World Meteorological Organization (WMO), REPORT No. 51, WMO/TD-No. 1437, p. 178



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