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VACANCY DISTRIBUTION STUDIES AT MULTIPLE IONIZATION IN HIGH-ENERGY
ION-ATOM COLLISIONS
I. Kádár, S. Ricz, D. Varga, B. Sulik, J. Végh, D. Berényi
To cite this version:
I. Kádár, S. Ricz, D. Varga, B. Sulik, J. Végh, et al.. VACANCY DISTRIBUTION STUDIES AT MULTIPLE IONIZATION IN HIGH-ENERGY ION-ATOM COLLISIONS. Journal de Physique Col- loques, 1987, 48 (C9), pp.C9-285-C9-288. �10.1051/jphyscol:1987950�. �jpa-00227368�
VACANCY DISTRIBUTION STUDIES AT MULTIPLE IONIZATION IN HIGH-ENERGY ION-ATOM COLLISIONS
/ /
I. KADAR, S. RICZ, D . VARGA, B. S U L I K , J . VEGH and D . BERENYI
I n s t i t u t e of Nuclear Research of t h e Hungarian Academy of S c i e n c e s , Pf. 5 1 , H-4001 Debrecen, Hungary
Abstract
- Preliminary results of the evaluation of Ne I(-Auger spectra obtained in 5.5 MeV/u heavy-ion-
Ne collisions are presented. The evaluation and identification is based on the measured series of spectra rather than on the evaluation of a representative one.Introduction
- Neon K-Auger spectra obtained in high-energy heavy ion-atom collisions are generally of very complex structure except for the very high or very low projectile ion charge states. Matthews and his coworkers 111 have determined the energy and in many cases also the relative intensity of 67 lines in the Ne I(-Auger spectrum from the 33 MeV 05+-Ne collision.Other authors [2] analyzed more simple spectra, or part of the K-Auger spectrum [3,4]. We attempted to analyze in details the high resolution (cca 1 eV) neon K D Auger spectra from the 5.5 MeV/u
H+, N2+,
Ne3+, NelO+, Ar6+ [3,4,5] and Arl6+-neon collisions. The spectra have been measured at the beam of the heavy-
ion cyclotron U-300 in Dubna, except for the H+-neon one measured at the Debrecen cyclotron [3,4,5].Evaluation of spectra
- By evaluating the spectra in details, i.e. by determining the energies and intensities of the individual spectrum components one gets spectroscopical information on the more or less ionized species of the target atoms by identifying the different satellite and diagram transitions. From the intensity of the identified transitions one can determine the population of the individual ionic levels or configurations by the help of calculated 161 or measured branching ratios. From the populations one can deduce the cross section of their production and from their relative values the vacancy distribution in the target.The task to determine the position and intensity of all the components of these complex spectra is not well defined in the case of a single spectrum. To overcome this difficulty we try to use the advantage given by the fact that we have measured a long series of spectra, i.e. fiom the simplest Ne I<-Auger spectrum from a H+-Ne collision up to the most complicated one obtained from the NelO+-Ne collision. Due to the fact that these spectra contain the transitions from different vacancy configurations .in different proportion, one may hope to extract useful
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1987950
C9-286 JOURNAL DE PHYSIQUE
information from them concerning the production cross section of different configurations and possibly also of some multiplet terms.
We adopted the following method of analysis. At first we assign the peaks in the spectra to different electron configurations according to the intensity ratios of these lines found a t the same energy in different spectra. Figure 1 shows an example of the intensity ratios obtained when comparing the intensities of two spectra measured with projectiles of different charge states. Then, beginning with the simplest spectra we determine the intensity ratio of different transitions from the one L vacancy and the two and three L electron configurations. Using this ratios we evaluate the one step more complicated spectra and check whether the previous tentative identification was correct or not. Bringing back this information to the previously evaluated, more simple spectrum, we can refine the intensity and energy values obtained this way until this iteration does not change the data any more. Continuing the procedure this way one can evaluate further target charge states, bearing in mind that after all one probably can not identify all the transitions present in the spectrum. At the identification of the individual spectrum components we use not only their relative intensities in the given spectrum and their relative and absolute energy position, but the tendencies of their absolute and relative intensities found in function of the projectile charge.
Fig. 1 Comparison of the intensities of the peaks found at the same energy in the 646
-
714 eV energy range of target K-Auger spectra taken at the 5.5 MeV/u Ne3+-Ne and Ar16+-Ne collisionsV) 1: m aJ
(I U- 0 6 -
The detailed evaluation procedure is in progress. The results until now: identification of most of the Li - like, Be - like and K L - LLL ionization satellites, as well as the diagram transitions (Tables 1-3; errors given for the energy values do not contain the calibration error which amounts about 0.1 eV). All the intensive lines are assigned to a configuration, so we could establish the L-vacancy distribution in the target in the case of two projectiles. From the average number of L-vacancies vacancy production probability values have been deduced for one L-shell electron in the case of these two collisions, namely 0.19 in the case of the 5.5 MeV/u Ne3+-Ne and 0.33 in the case of NelO+-Ne collisi~n. These values agree with those determined from the diagramJtota1 ratio [7].
Be-Like B - Like C-Like N - L i k e
* Transitions having no au.signntent are identified aa Be-like ones becaase they belong to the sarne inten.9ity ratio group as the assigned ones when co9nparing the intensities in two diflerent spectra.
Transition*
121 3 P 3 201 2 P 112 5P 3 201 'P
121 ' P 3 201 2 P
121 3 P 3 210 2 S 112 3P+ 201 ' P 112 5 P 3 210 2 S 112 3 D 3 201 2 P
Table 2 The group of Ne IC-Auger transitions from Li-like initial states 691.91 (5)
Energy Present Theory[8]
666.G9 (7) 669.9 GG9.G7(14) 670.2 670.44 (7)
671.48 (7) 672.64(18) 674.87(10)
676.14 (4) 676.3 677.26 (5)
678.43 (4) 682.25(13)
683.04(9) 686.1 684.00(20) 684.8 685.76(12) 686.4 686.36(18) 685.4 688.57(23) 689.79(13)
* The transition having no assignment is identified as Li-like one because it belongs to the same intensity ratio group a s the nssagned ones when comparing the intensities in tzoo different spectra.
Relative intensity '
total group int.=l.
0.046(5) 0.035 (7) 0.01 l(2) 0.028(3) 0.012(1) 0.030(3) 0.015(2) 0.016(1) 0.017(2) 0.029(9) 0.046(10) 0.061(16) 0.088(15) 0.037(13) 0.048(5) 0.062(10)
Transition*
120 2 S
+
200 111 4 P a 200 l S Li - like core++spectator 111 2P+ 3 200 ' S 111 ' P - 3 200 102 4 P 3 200 102 ' 0 3 200
Energy Present Theory [8]
652.23(12) 656.4 656.49 (7) 656.2 660.10 (9) 662.06(6) 665.71(21) 668.44(19) 668.7 673.45(11) 675.8 674.11(12) 673.9 680.61 (8) 682.3
Ilelative intensity total group int.=l.
0.046(2) 0.346(41)
0.007(2) 0.008(3) 0.026(8) 0.074(18) 0.222(46) 0.137(40) 0.135(18)
C9-288 JOURNAL DE PHYSIQUE
Table 3 The group of Ne K-Auger transitions from KL initial states
* An abbreviated spectroscopical notation [I] is used in the tables (1312s22p5 = 125)
Transition*
1 2 5 3 P
*
2 0 5 2 P 125 lp 3 205 2P 125 3P+
214 2P 125 3f'+
2142s
125 'P
*
214 2P125 3P
+
214 2 D 125 ' P+-
214 2L) 125 3P 3 214 * P 125 3P+
223 2P 1163s +
2142o
125 3P
+
223 2 D 125 'P 3 2232P
125 'P
+
223 2D 116 '5 214 2 DAcknowledgement
- The authors acknowledge the contribution of the operating crew of the U-300 heavy-ion cyclotron in Dubna as well as that of the crew of the Debrecen cyclotron to these results. Thanks are due to the Academic Research Fund of the Hungarian Academy of Sciences for partly sponsoring this work. The high quality technical assistance by Mr. J. Koblos and Mr.L. Barta is also acknowledged.
References
Energy Present Theory[8) 731.01 (4) 731.3 735.55 (4) 735.4 751.51 (4) 751.0 753.27 (4) 754.7 755.84 (4) 755.1 759.59 (4) 760.2 763.87 (4) 764.3 768.34 (6) 770.3 783.35 (4) 784.1 785.51(10) 788.2 786.04(10) 787.8 787.80 (4) 788.2 790.48 (4) 791.9 792.37 (5) 795.7
[l] Matthews
(D.
L.), Johnson (B. M.), Mackey (J. J.), Smith (L. E.), Hodge (W.) and Moore (C. F.), Phys.Rev., 1974,A 10, 1177.[2] Mann (R), Folkmann (F) and Beyer (H. F.), J.Phys.B, 1981, 14, 1161.
131 KMG (I.), Ricz (S.), Shchegolev (V. A,), Varga (D.), Vdgh (J.), Berdnyi (D.), Hock (G.) and Sulik (B.), Phys.Lett., 1986, A115, 439.
[4] Ricz (S.), KQdir (I.), Shchegolev (V. A.), Varga (D.), Vdgh (J.), Berdnyi (D.), Hock (G.) and Sulik (B.), J.Phys.B, 1986, 19, L411.
[5] Sulik (B.), KAdir
(I.),
Ricz (S.), Varga (D.), Vkgh ( J . ) , Hock (G.) and Berdnyi (D.), ATOMKI preprint, 1987, B/19, Nucl. Instr. Meth., to be published6 Bhalla (C. P.), J. El. Spy. Rel. Phenom., 1975, 7, 287.
7 KAdAr (I.), Ricz (S.), Shchegolev (V. A.), Sulik (B.), Varga (D.), VQgh (J.), Ber6nyi (D.) and
I1
Hock (G.), J.Phys.B, 1985, 18, 275.(81 Maurer (R. J.) a n d \ITa.t>son (R. L.),At. Nucl. Data Tables, 1986, 34, 185.
Relative intensity total group int.= 1.
0.068(7) 0.034(5) 0.051(5) 0.022(2) 0.070(10)
0.094(9) 0.016(3) 0.030(3) O.lOO(9) 0.131(8) 0.208(19)
0.050(7) 0.102(14)
0.031 (1)
