Canadian Journal of Physics

Journal canadien de physique

Published by Publik par THE NATIONAL RESEARCH COUNCIL OF CANADA LE CONSEIL NATIONAL DE RECHERCHES D U CANADA

Volume 55 Number 16 August 15, 1977 Volume 55 numCro 16 15 aoQt 1977

A new satellite in the L X-ray emission spectrum of lutetium-71

X-Rcry Laborcrtorirs, Deprirt~ner~t of Plf)lsics, University ofJodhplrr, Jodhprrr, India Received February 18, 1977

Using a 40cm curved mica crystal spectrograph of the transmission (Cauchois) type, a new satellite [ j I 4 has been observed at h = 1408.3 X unit (Xu) in the L X-ray emission spec- trum of lutetium-71 for the first time. On the basis of Wentzel's multiple ionization theory the new satellite has been assigned to the transition L2M4 + M4M4. Further, the presence of the satellites ax, BZ1, and y,' in the spectrum of lu te t i~~m reported by earlier workers, has been confirmed and these satellites have been assigned to the transitions L3M2 + MzM5, L3M5 + M5N5, and L2M4 + M4N4, respectively.

En utilisant un spectrographe a cristal de mica incurvt de 40 cm, du type a transmission (Cauchois), on a observe pour la premiere une nouvelle raie satellite Bl4, A h = 1408.3 uX, dans le spectre d'Cmission L du lutCtium 71. En se basant sur la thCorie de I'ionisation multiple de Wentzel, on a attribuC cette nouvelle raie satellite A la transmition L2M4 -, M4M4. De plus, la presence, rapportCe antirieurement par d'autres chercheurs, des satellites ax, [j2' et y,' dans le spectre du lutCtium a CtC confirmke, et ces raies satellites ont CtC associees respectivement aux transitions L3Mz + M2M5, L3M5 -, M5N5 et L2M4 + M4N4.

[Traduit par le journal] Can. J . Phys., 55, 1385 (1977)

Introduction The existence of high frequency satellites

in the X-ray emission spectra is well estab- lished. Numerous such satellites have been compiled in the wavelength tables (Cauchois and Hulubei 1947). The first theory (Wentzel 1921) of origin of these satellites attributing these lines to single electronic transitions in atoms with double vacancies in the inner shells is generally accepted. A recent and up-to-date survey on the high frequency satel- lites has been presented (Ninam and Mathur . - 1972).

In continuation of our broad plan for re- cordinn the hitherto unobserved satellites in the L spectra of some heavy elements, we pre- sent in this paper results. of our studies on the L spectrum of lutetium-71.

Experimental Procedure The experimental set up was the same as

described earlier (Nigam et 01. 1968). However, in the present study, the copper anticathode was replaced by a massive iron anticathode and a tantalum filament instead of the tungsten one was used in the cathode assembly of the demountable X-ray tube. The X-ray tube was operated at 20 kV, 3-4 mA (full wave rec- tified), and the exposure time ranged from 15 to 30 h. A 40 cm curved mica crystal spectro- graph, with the (100) planes of mica reflecting in the first order was used to record the spec- trum on the Industrial X-ray films. Spectro- graphically standardized powder of Lu203 (sup- plied by M/S Johnson Matthey and Co., London) was used for preparing the lutetium target. A Hilger comparator of least count

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1386 CAN. J. PHYS. VOL. 5 5 . 1977

0.0001 cm was used to ineasure the wavelengths directly on negatives. Our measured values represent the mean of a large number of sep- arate and independent measurements. The ac- curacy of our measurements is f 0.1 X unit (Xu).

Results In the present study we have, for the first

time, co~lclusively established the existence of a new satellite LP,, a t h = 1408.3 Xu in the spectrum of lutetium. This has been as- signed to the transition L2M4 + M,M,. The presence of the satellites K ~ , P,', and y,' re- ported by earlier workers has been confirmed and these have been assigned to the transitions L3M2 + M2M5, L3M5 + M5N5, andL2M4 +

M4N4, respectively.

Discussion (i) The Satellite LP,, (L2M4 -, M,M,) h =

1408.3 Xu In the systematic studies (Nigam and Mathur

1974) on the L X-ray emission spectrum of tungsten-74, we have reported the presence of a new satellite LP,, at h = 1268.84 Xu. In our present study, all our long exposure spectrograms show a clear trace of a line be- tween LuLP,(h = 1416.1 Xu) and LuLP3(h = 1398.50 Xu). Taking these as reference lines, the measured value of the wavelength of this line comes out to be h = 1408.3 Xu. As has already been discussed (Nigam and Mathur 1974) we have assigned this line to the transi- tion L2M4 + M,M, showing that the parent is LPl and the second vacancy exists in the M, subshell. The calculated value of the wave- length of this satellite is 1408.1 Xu which shows the excellent agreenlent with the wavelength (h = 1408.3 Xu) ineasured by us.

(ii) TIE Satellite LmX (L3M2 + M2M5) h =

1609.7 Xu The satellite LxT has been reported in the

spectra of almost all the elements with 62 < Z < 83. In the spectrum of lutetium this has been reported a t h = 1609.7 Xu by earlier workers (Cauchois and Hulubei 1947). Recent studies (Kapoor et al. 1969) have reported its presence at h = 1609.9 Xu. In our present study we have observed this satellite at h = 1609.7 Xu. This line has been assigned (Kapoor et al. 1969) to the transition L3M1 + M l M 5 (I,,, = 1608.56 Xu). However, we prefer to assign this line to the transition L3M2 +

M2M5 (kc,, = 1610.83 Xu). This is because

earlier studies (Kapoor et al. 1969) have been restricted to the rare earth elements only, whereas we have taken into consideration all the elements of the periodic table and have found that our assignments give better numerical agreement in allnost all the cases.

(iii) Tlze Satellite LP,' (L3M5 -+ M5N5) h = 1358.6 Xu

The satellite LP2' has been observed in the spectra of the elements with 46 < Z < 82. In earlier studies (Cauchois and Hulubei 1947) this satellite in the spectrum of lutetium-71 has been reported at h = 1356.8 Xu. Later studies (Garg et 01. 1971) have reported its presence at 1358.7 Xu and have assigned it to the transition L3M4 + M4M, (A,,, = 1358.45 Xu). In our present study we have observed this satellite at h = 1358.6 Xu. On the grounds of the arguments presented in (ii) we prefer to assign it to the transition L3M5 +

M5N5(hc,, = 1359.26 Xu).

(iv) The Satellite Ly, ' (L,M, + M4N4) 3L = 1210.7 Xu

The satellite Ly,' has so far been reported (Cauchois and Hulubei 1947) in the spectra of almost all the elements with 49 < Z < 83. In the spectrum of lutetium this satellite has been reported a t h = 121 1.9 Xu by earlier workers (Cauchois and Hulubei 1947). Later studies (Kapoor et ul. 1970) have reported its presence a t h = 1212.0 Xu and have as- signed it to the transition L2M3 + M3N, (kc,, = 1212.04 Xu). In our present study we have observed this satellite at h = 1210.7 Xu. However, in view of the arguments extended in (ii) we have preferred to assign it to the transition L2M4 -t M4N4 (h,,, = 1212.69 Xu).

CAUCHOIS, Y. and HULUBEI, H. 1947. Tables de con- stantes et donnees numeriques L - longueurs d'ondes des emission X - et des discontinuites d'absorption X. Herman, Pans.

GARG, K. B., KAPOOR, (2. S., and NIGAM, A. N. 1971. J. Phys. B, 4,739.

KAPOOR, Q. S . , GARG, K. B., and NIGAM, A. N. 1969. Phys. Lett. 30,228.

1970. J. Phys. B, 3, 1180. NIGAM, A. N. and MATHUR, R. B. 1972. Proceedings of the

International Conference on Inner Shell Ionization phenomena and its future Applications, Atlanta, GA, U.S.A. April 17-22. p , 1598.

1974. Chem. Phys. Lett. 28.41. NIGAM, A. N., GARG, K . B., and KAPOOR, Q. S. 1968. J.

Phys. B, 1,492. WENTZEL, G. 1921. Ann. Phys. (Leipzig), 66,437.

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