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Condensed-state effects in muonic X-ray spectra
Volume 26B, number 5
PHYSICS
LETTERS
5 February 1968
CONDENSED-STATE E F F E C T S IN MUONIC X-RAY SPECTRA H. D A N I E L *, H. KOCH **, G. P O E L Z *, H. S C H M I T T *, L. T A U S C H E R * G. B A C K E N S T O S S ** and S. C H A R A L A M B U S CERN, Geneva, Switzerland Max-Planck-Institut ff~r Kernphyik, Heidelberg, Germany and Institut p~r Experirnentelle Kernphyik der Universitiit Karlsruhe, Germany Received 29 December 1967
Intensity measurements of muonic X - r a y s in targets of different physical or chemical composition are reported.
C h e m i c a l e f f e c t s h a v e b e e n found in m e s i c X - r a y s p e c t r a [1,2]. K e s s l e r et a l . [2] o b t a i n e d big i n t e n s i t y - r a t i o d i f f e r e n c e s b e t w e e n the s a m e T i l i n e s f r o m T i and T i O 2 t a r g e t s , r e s p e c t i v e l y . We want to r e p o r t d a t a on i n t e n s i t y r a t i o s m e a s u r e d with m u o n s f o r t a r g e t s d i f f e r i n g in c h e m i c a l or physical composition. The set-up making use of a Ge d e t e c t o r and a s c i n t i l l a t i o n c o u n t e r t e l e s c o p e has a l r e a d y b e e n d e s c r i b e d [3]. T a b l e 1 s u m m a r i z e s the t a r g e t s and the r e s u l t s . C o l u m n 1 c o n t a i n s the two t a r g e t s in c o m p a r i s o n , c o l u m n 2 the e l e m e n t of which the X r a y s a r e i n v e s t i g a t e d . In c o l u m n 3 the two t r a n sitions are given whose intensity ratio is formed s e p a r a t e l y f o r e a c h t a r g e t . In c o l u m n 4 the e x p e r i m e n t a l v a l u e s a r e l i s t e d , e.g. in t h e f i r s t l i n e of the t a b l e the r a t i o b e t w e e n the two i n t e n sity ratios [ ( 3 p - l s ) / ( 2 P - ls)](CH2)n
Table 1 Experimental results Target pair
Element
Transitions
Ratio of intens, ratios
CH 2 / C graphite
C
3p-ls/2p-ls 4p-ls/2p-ls 5p-ls/2p-ls
1.25 ± 0.05 1.64±0.07 1.99±0.15
H2180/H2160
O
3p-ls/2p-ls 4p-ls/2p-ls
1.20±0.17 0.95 ± 0.15
A1203/H2160
O
3p-ls/2p-ls 4p-ls/2p-ls 5p-ls/2p-ls
0.77 ± 0.04 0.64 ± 0.04 0.57±0.06
SIO2/H2160
O
3p-ls/2p-ls 4p-ls/2p-ls
0.82 ± 0.05 0.70±0.05
CaO/H2160
O
4p-ls12p-ls
0.9 ~:0.3
TiO2/H2160
O
3p-ls/2p-ls
0.81 ± 0.05
NaC1/Name t
Na
3p-ls/2p-ls
0.83 ± 0.10
A1203/Alme t
A1
3p-ls/2p-ls 4p-ls/2p-ls 5p- l s / 2 p - ls 3d-2p/2p-ls 4d-2p/3d-2p 5d-2p/3d-2p
0.90 ± 0.02 0.83 i 0.02 0.70±0.02 1.04±0.02 1.40 ± 0.08 0.93 ± 0.10
CaO/Ca
Ca
5 f-3d/4 f-3d
0.76±0.25
TiO2/Ti
Ti
3d-2p/2p-ls 4d-2p/3d-2p 4 f-3d/3d-2p
1.18 ± 0.07 0.87±0.17 1.51±0.20
[ (3P- l s ) / ( 2 P - 1 s)]C graphite The results are corrected for self absorption. T h e e r r o r s a r e m e a n t to be s t a n d a r d d e v i a t i o n s . T h e T i O 2 - T i r e s u l t a g r e e s with that of K e s s l e r et al. [2]. T h e r e is no s i g n i f i c a n t d i f f e r e n c e b e t w e e n the r e s u l t s f r o m 180 and 160. D i f f e r e n c e s would be e x p e c t e d if n u c l e a r r e c o i l e f f e c t s w e r e to p l a y a d o m i n a n t r61e. In m o s t of t h e o t h e r t a r g e t p a i r s d i f f e r e n c e s * Visitor at CERN from the Max-l~lanck-Institut f~r Kernphysik, Heidelberg, Germany. ** Visitor at CERN from the Institut ffir Experimentelle Kernphysik der Universit~it, Karlsruhe, G e r many.
a r e found. T h e m o s t p r o n o m l c e d e f f e c t s o c c u r if one t a r g e t m a t e r i a l is a good i n s u l a t o r and the o t h e r i s not. On the o t h e r hand all oxygen data f o r A1203, SiO 2 and T i O 2 a g r e e . T h e i n t e r p r e t a t i o n of o u r e x p e r i m e n t a l r e s u l t s i s d i f f i c u l t . In o u r opinion two e f f e c t s could be r e s p o n s i b l e : the C o u l o m b c a p t u r e and the 281
Volume 26B, number 5
PHYSICS LETTERS
A uge r and X - r a y c a s c a d e . The A u g e r t r a n s i t i o n r a t e s which, with e l e c t r o n s a v a i l a b l e , d o m i n a t e at low e n e r g i e s depend on the p r o b a b i l i t y of e l e c t r o n s f o r c o n v e r s i o n being a v a i l a b l e . As the n u m b e r of c a s c a d e t r a n s i t i o n s between the C o u l o m b c a p t u r e s t at e and, say, the l s l e v e l of the m e s i c atom is l a r g e and as an e l e c t r o n hole is v e r y f r e q u e n t l y f i l l e d by an A u g e r t r a n s i t i o n this p r o b a b i l i t y will depend on the supply of e l e c t r o n s f r o m outside. T h i s m a y explain the o b s e r v e d c o r r e l a t i o n with the conductivity.
282
5 February 1968
1. V.G.Zinor, A.D.Konin, A.I.Mukhin and P.V. Polyakov, quoted in ref. 2. 2. D.Kessler, H.L.Anderson, M.S. Dixit, H.J.Evans, R.J.McKee, C.K. Hargrove, R.D.Barton, E . P . Hineks and J.D. MeAndrew, Phys. Rev. Letters 18 (1967) 1179. 3. H.Daniel, G.Poelz, H.Schmitt, G.Backenstoss, H. Koch and St. Charalambus, Z. Physik 205 (1967) 472.
PHYSICS
LETTERS
5 February 1968
CONDENSED-STATE E F F E C T S IN MUONIC X-RAY SPECTRA H. D A N I E L *, H. KOCH **, G. P O E L Z *, H. S C H M I T T *, L. T A U S C H E R * G. B A C K E N S T O S S ** and S. C H A R A L A M B U S CERN, Geneva, Switzerland Max-Planck-Institut ff~r Kernphyik, Heidelberg, Germany and Institut p~r Experirnentelle Kernphyik der Universitiit Karlsruhe, Germany Received 29 December 1967
Intensity measurements of muonic X - r a y s in targets of different physical or chemical composition are reported.
C h e m i c a l e f f e c t s h a v e b e e n found in m e s i c X - r a y s p e c t r a [1,2]. K e s s l e r et a l . [2] o b t a i n e d big i n t e n s i t y - r a t i o d i f f e r e n c e s b e t w e e n the s a m e T i l i n e s f r o m T i and T i O 2 t a r g e t s , r e s p e c t i v e l y . We want to r e p o r t d a t a on i n t e n s i t y r a t i o s m e a s u r e d with m u o n s f o r t a r g e t s d i f f e r i n g in c h e m i c a l or physical composition. The set-up making use of a Ge d e t e c t o r and a s c i n t i l l a t i o n c o u n t e r t e l e s c o p e has a l r e a d y b e e n d e s c r i b e d [3]. T a b l e 1 s u m m a r i z e s the t a r g e t s and the r e s u l t s . C o l u m n 1 c o n t a i n s the two t a r g e t s in c o m p a r i s o n , c o l u m n 2 the e l e m e n t of which the X r a y s a r e i n v e s t i g a t e d . In c o l u m n 3 the two t r a n sitions are given whose intensity ratio is formed s e p a r a t e l y f o r e a c h t a r g e t . In c o l u m n 4 the e x p e r i m e n t a l v a l u e s a r e l i s t e d , e.g. in t h e f i r s t l i n e of the t a b l e the r a t i o b e t w e e n the two i n t e n sity ratios [ ( 3 p - l s ) / ( 2 P - ls)](CH2)n
Table 1 Experimental results Target pair
Element
Transitions
Ratio of intens, ratios
CH 2 / C graphite
C
3p-ls/2p-ls 4p-ls/2p-ls 5p-ls/2p-ls
1.25 ± 0.05 1.64±0.07 1.99±0.15
H2180/H2160
O
3p-ls/2p-ls 4p-ls/2p-ls
1.20±0.17 0.95 ± 0.15
A1203/H2160
O
3p-ls/2p-ls 4p-ls/2p-ls 5p-ls/2p-ls
0.77 ± 0.04 0.64 ± 0.04 0.57±0.06
SIO2/H2160
O
3p-ls/2p-ls 4p-ls/2p-ls
0.82 ± 0.05 0.70±0.05
CaO/H2160
O
4p-ls12p-ls
0.9 ~:0.3
TiO2/H2160
O
3p-ls/2p-ls
0.81 ± 0.05
NaC1/Name t
Na
3p-ls/2p-ls
0.83 ± 0.10
A1203/Alme t
A1
3p-ls/2p-ls 4p-ls/2p-ls 5p- l s / 2 p - ls 3d-2p/2p-ls 4d-2p/3d-2p 5d-2p/3d-2p
0.90 ± 0.02 0.83 i 0.02 0.70±0.02 1.04±0.02 1.40 ± 0.08 0.93 ± 0.10
CaO/Ca
Ca
5 f-3d/4 f-3d
0.76±0.25
TiO2/Ti
Ti
3d-2p/2p-ls 4d-2p/3d-2p 4 f-3d/3d-2p
1.18 ± 0.07 0.87±0.17 1.51±0.20
[ (3P- l s ) / ( 2 P - 1 s)]C graphite The results are corrected for self absorption. T h e e r r o r s a r e m e a n t to be s t a n d a r d d e v i a t i o n s . T h e T i O 2 - T i r e s u l t a g r e e s with that of K e s s l e r et al. [2]. T h e r e is no s i g n i f i c a n t d i f f e r e n c e b e t w e e n the r e s u l t s f r o m 180 and 160. D i f f e r e n c e s would be e x p e c t e d if n u c l e a r r e c o i l e f f e c t s w e r e to p l a y a d o m i n a n t r61e. In m o s t of t h e o t h e r t a r g e t p a i r s d i f f e r e n c e s * Visitor at CERN from the Max-l~lanck-Institut f~r Kernphysik, Heidelberg, Germany. ** Visitor at CERN from the Institut ffir Experimentelle Kernphysik der Universit~it, Karlsruhe, G e r many.
a r e found. T h e m o s t p r o n o m l c e d e f f e c t s o c c u r if one t a r g e t m a t e r i a l is a good i n s u l a t o r and the o t h e r i s not. On the o t h e r hand all oxygen data f o r A1203, SiO 2 and T i O 2 a g r e e . T h e i n t e r p r e t a t i o n of o u r e x p e r i m e n t a l r e s u l t s i s d i f f i c u l t . In o u r opinion two e f f e c t s could be r e s p o n s i b l e : the C o u l o m b c a p t u r e and the 281
Volume 26B, number 5
PHYSICS LETTERS
A uge r and X - r a y c a s c a d e . The A u g e r t r a n s i t i o n r a t e s which, with e l e c t r o n s a v a i l a b l e , d o m i n a t e at low e n e r g i e s depend on the p r o b a b i l i t y of e l e c t r o n s f o r c o n v e r s i o n being a v a i l a b l e . As the n u m b e r of c a s c a d e t r a n s i t i o n s between the C o u l o m b c a p t u r e s t at e and, say, the l s l e v e l of the m e s i c atom is l a r g e and as an e l e c t r o n hole is v e r y f r e q u e n t l y f i l l e d by an A u g e r t r a n s i t i o n this p r o b a b i l i t y will depend on the supply of e l e c t r o n s f r o m outside. T h i s m a y explain the o b s e r v e d c o r r e l a t i o n with the conductivity.
282
5 February 1968
1. V.G.Zinor, A.D.Konin, A.I.Mukhin and P.V. Polyakov, quoted in ref. 2. 2. D.Kessler, H.L.Anderson, M.S. Dixit, H.J.Evans, R.J.McKee, C.K. Hargrove, R.D.Barton, E . P . Hineks and J.D. MeAndrew, Phys. Rev. Letters 18 (1967) 1179. 3. H.Daniel, G.Poelz, H.Schmitt, G.Backenstoss, H. Koch and St. Charalambus, Z. Physik 205 (1967) 472.