RESONANT COHERENT EXCITATION OF
LI-LIKE URANIUM
Y. Nakano1 , Y. Takano2 , T. Ikeda3 , Y. Kanai3 , S. Suda1,4,T. Azuma1,4, H. Br¨auning5, A. Br¨auning-Demian5, Th. St¨ohlker5
, D. Dauvergne6
, Y. Yamazaki2,3 1
AMO Physics Laboratory, RIKEN, Japan
2
Graduate School of Arts and Sciences, Univ. of Tokyo, Japan
3
Atomic Physics Laboratory, RIKEN, Japan
4
Department of Physics, Tokyo Metropolitan University, Japan
5
Gesellschaft f¨ur Schwerionenforschung (GSI), Germany
6
IPNL, Universit´e Lyon 1, CNRS/IN2P3, France
An ion passing through a mono-crystalline target gfeelsh an os-cillating electric field with frequencies determined by its velocity and the crystal indices. When the frequency fits the energy dif-ference between the two levels of the ions, a so-called resonant coherent excitation (RCE) sets off. We have been intensively studying dynamic aspects of the RCE process with gmedium-heavyh highly-charged ions (Z = 18 or 26) of ∼400 MeV/u [1,2,3] at NIRS-HIMAC, Japan.
Here we report on commissioning experiments for applying the 2D (two-dimensional)-RCE process to a high resolution spec-troscopy of gheavyh highly-charged ions employing ion beams supplied from the SIS at GSI. We concentrated on a transition of 1s22s1/2-1s22p3/2(the transition energy is 4459 eV) of 191.5 MeV/u
Li-like U89+
ions. A well collimated beam with small diver-gence passed through the (220) atomic plane of a 7µm-thick Si crystal mounted on a goniometer. We tuned the resonance con-dition by rotating the crystal with respect to the beam direction,
and observed the resonance through enhancement of the x-ray yield emitted from the RCE-excited ions. Four silicon drift de-tectors (SDD) equipped with a large detection area (100 mm2
) detected the de-excitation x-rays with high efficiency. As shown in the figure below, we succeeded in observing a strong reso-nance peak, and have proven the feasibility of applying the RCE scheme to this collision system.
1s22s RCE 4459 eV X-ray 1s22p 3/2 1s22p 1/2 Li-like U89+ 0 2 4 6 8 10 4.2 4.4 4.6 4.8 5.0 5.2 4450 4455 4460 4465
Incident angle θ [deg.] Transition energy [eV]
X-ray yield [arb.]
The present scheme is quite universal for various ions for a wide range of transition energies including hyperfine splitting of un-stable nuclei, i.e., once the feasibility of the heavy ion RCE tech-nique is established for high precision spectroscopy, a lot of ap-plications would emerge in the field of atomic as well as nuclear physics.
References
[1] Y. Nakano et al., Phys. Rev. Lett. 102 (2009) 085502. [2] C. Kondo et al., Phys. Rev. Lett. 97 (2006)135503. [3] Y. Nakai et al., Phys. Rev. Lett. 101 (2008)113201.
EUV SPECTROSCOPY OF HIGHLY
CHARGED IONS WITH HIGH- AND
LOW-ENERGY EBITS
YATSURUGI Junji, WATANABE Etsushi, OHASHI Hayato,
SAKAUE Hiroyuki A.*, NAKAMURA Nobuyuki Institute for Laser Science, The University of Electro-Communications, Tokyo 182-8585, JAPAN
(*) National Institute for Fusion Science
Spectral data of multiply charged ions in the EUV region are needed in several areas. For example, to develop an EUV light source for the next-generation lithography, the atomic data of Sn ions are strongly needed. The atomic data of Fe ions are needed for the spectroscopic diagnostics of the solar atmosphere. For the next-generation fusion device ITER, the spectroscopic data of W ions are needed. We have been accumulating such spectral data using two EBITs in Tokyo; one of them is the Tokyo-EBIT [1] designed for the operation with a high energy electron beam, and another is “CoBIT” [2] designed for low electron energy operation. In addition to the grazing incidence flat-field grating spectrometer [3] designed for CoBIT, we have recently devel-oped a new grazing incidence spectrometer for the Tokyo-EBIT. Spectra obtained with these spectrometers are presented.
References
[1] N. Nakamura et al., Phys. Scr. T73, 362 (1997).
[2] N. Nakamura et al., Rev. Sci. Instrum. 79, 063104 (2008). [3] H.A. Sakaue et al., J. Phys.: Conf. Ser. 163, 012020 (2009).
Visible spectroscopy of Rh-like ions
SAKODA Junpei, KOMATSU Akihiro, KIKUCHI Hiroyuki,
NAKAMURA Nobuyuki
Institute for Laser Science, The University of Electro-Communications, Tokyo 182-8585, JAPAN
M1 transitions between ground-state fine-structure levels in highly charged ions are useful for plasma diagnostics especially when the transition wavelength falls in the visible range. Thus iden-tifications and wavelength measurements of such transitions are strongly needed. Accurate wavelength measurements are also important to test the theories of relativistic many-electron sys-tems.
In the present study, we have observed the visible transition be-tween ground-state fine-structure levels, 4d9 2D, of Rh-like Ba
using a compact electron beam ion trap in Tokyo [1]. The ex-perimentally obtained wavelength is compared with theoretical calculations [2]. The same transition in Rh-like Xe has also been observed, and the result is compared with the previous measure-ment by Tak´acs [3] as well as theories.
References
[1] N. Nakamura et al., Rev. Sci. Instrum. 79, 063104 (2008). [2] Y. Liu, private communications.
VISIBLE SPECTROSCOPY OF HIGHLY
CHARGED TUNGSTEN IONS
KOMATSU Akihiro, SAKODA Junpei,
WATANABE Hirofumi*, SAKAUE Hiroyuki A.†, KATO Daiji†, MURAKAMI Izumi†, NAKAMURA Nobuyuki
Institute for Laser Science, The University of Electro-Communications, Tokyo 182-8585, JAPAN
(*) Chubu University
(†) National Institute for Fusion Science
Tungsten is a major candidate for the divertor material of ITER, so that its spectroscopic data are strongly needed to diagnose and control the high temperature plasma in ITER. By using two EBITs in Tokyo [1,2], we are systematically measuring spec-tra of highly charged tungsten ions with a wide range of charge states over a wide range of wavelength. In particular, we are currently interested in the visible region because a lot of effort has already been paid for the shorter wavelength range such as VUV and X-rays at the Berlin EBIT [3]. The charge state of the tungsten ion responsible for observed lines was identified from the appearance energy by observing electron energy dependence. For the detailed identification of the lines, comparisons with the-oretical calculations were also made.
References
[1] N. Nakamura et al., Phys. Scr. T73, 362 (1997).
[2] N. Nakamura et al., Rev. Sci. Instrum. 79, 063104 (2008). [3] R. Radtke et al., Phys. Rev. A 64, 012720 (2001).
M
F-DEPENDENT HYPERFINE INDUCED
TRANSITION RATES IN AN EXTERNAL
MAGNETIC FIELD
Jiguang Li, Chenzhong Dong, Per J¨onsson∗, Gediminas
Gaigalas†,‡
College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, China
Joint Laboratory of Atomic and Molecular Physics, NWNU & IMP CAS, Lanzhou 730070, China
(∗) Center for Technology Studies, Malm¨o University, Malm¨o
S-20506, Sweden
(†) Department of Physics, Vilnius Pedagogical University,
Studentu¸ 39, Vilnius LT-08106, Lithuania
(‡) Institute of Theoretical Physics and Astronomy, A. Gostautˇo
12, Vilnius LT-01108, Lithuania
Recently, the hyperfine induced transition (HIT) rate of the 2s2p3P
0
level for Be-like 47Ti ions has been measured with high
accu-racy in the heavy-ion storage-ring TSR of the Max-Planck In-stitute for Nuclear Physics, Heidelberg, Germany [1]. However, all present theoretical results [2, 3, 4] differ from the experimen-tal value by about 20%. Because the major part of the electron correlation has been taken into account in these accurate theoret-ical calculations, it is desirable to find out other reasons for the difference.
At present, we studied the effect of the external magnetic field present in the heavy-ion storage-ring on the HIT rate [5]. Rele-vant calculations were performed using GRASP2K [6] and HF-SZEEMAN package [7]. The HIT transition rate in an external
magnetic field depends on the magnetic quantum number MF
of the excited state, even in a relatively weak field. This effect, combined with the non-statistical distribution of the magnetic sublevel population of the excited level [8, 9], might lead to the difference in transition rate mentioned above.
References
[1] S. Schippers, E. W. Schmidt, D. Bernhardt, et al., Phys. Rev. Lett. 98, 033001 (2007)
[2] K. T. Cheng, M. H. Chen and W. R. Johnson, Phys. Rev. A 77, 052504 (2008)
[3] M. Andersson, Y. Zou, R. Hutton and T. Brage, Phys. Rev. A 79, 032501 (2009)
[4] J. G. Li and C. Z. Dong, Plasma Science and Technology (2010) (in print)
[5] J. G. Li, C. Z. Dong, P. J¨onsson and G. Gaigalas, Phys. Lett. A (2010) (Submitted)
[6] P. J¨onsson, X. He, C. Froese Fischer and I. P. Grant, Comput. Phys. Commun. 177, 597 (2007)
[7] M. Andersson and P. J¨onsson, Comput. Phys. Commun. 178, 156 (2008)
[8] F. H. Mies, Phys. Rev. A 7, 942, 957 (1973)
[9] Th. Stoehlker, D. C. Lonescu, P. Rymuza, et al. Phys. Rev. A 57 845 (1998)
BOUND BETA-DECAY AND DECAY
OF ISOMERIC STATES FOR NEUTRAL
ATOMS AND CORRESPONDING
MULTICHARGED IONS
A.V. Glushkov*, A.A. Svinarenko
Odessa University, PO.Box 24a, Odessa-9, 65009, SE, Ukraine Russian Academy of Sciences, Troitsk, 142090, Russia
*E-mail: glushkov@paco.net
Many attempts ha ve be en made t o influence o n the nuc lear decay r ate b y v arying chemical envi ronments etc or b y applying s trong electromagnetic fields. The s ituation is completely di fferent in hot stellar plasmas where the ions are partially or fully ionized (multicharged ions). In this case it can be ex pected that t he r ates of nuc lear b eta de cay and electron capture, as well as internal conversion, are strongly affected in comparison to those of neutral atoms [1]. In our paper the QED many-body perturbation theory is used to calculate the β decay parameters for a number of the beta-transitions. The relativistic calculation method is b ased on t he opt imized D irac-Kohn-Sham formalism with taking into account the nuclear, radiative and exchange-correlation c orrections [ 2]. W e have cal culated the probabilities of excitation to the final discrete states of 6Li+
(including to the doubly excited autoionizing states) as well as the total probabilities for single and double ionization. We have calculated be ta d ecay pa rameters f or a num ber o f t ransitions:
33P-33S, 35S-35Cl, 63Ni-63Cu, 241Pu-241Am etc and show that the
theoretical va lues a gree qui te w ell with some a vailable experimental data. We have studied the chemical environment effect on parameters of the β transitions, in particular, 63Ni(0)
-63Cu(+1), Ni(+2)-Cu(+3), 241Pu(0)-241Am(+1), Pu(+2)- Am(+3). T he
correct treatment of the chemical environment effect is shown to modify the be ta de cay p arameters ( the in tegral F ermi function, ha lf-life period, pr obability). This m odification is connected w ith account of a few factors ( changing t he integration limits in the F ermi f unction integral; the e nergy corrections f or di fferent che mical s ubstances as w ell as t he possibility of t he bou nd or ot her de cay ch annels). The estimates f or a r atio λb/λc of bound-state ( b) and c
ontinuum-state (c) beta de cay rates for the case of bare 207Tl81+ions and isomeric s tates of fully ioni zed 144mTb etc ar e g iven. T he
similar “multicharged ions” effects are also studied for 187Re. It
is found a giant increases of the half-lives of bare isomers by factors of up to 20 compared to their neutral counterparts. Such physical f actors as a strong i nternal conversion, electron-capture (bound be ta-decay) channels i n the r adioactive decay of these bare nuclei. The theoretical results are in a physically reasonable agreement with some experimental data [1].
References
[1] M. Jung et al., Phys. Rev. Lett. 69, 2164 ( 1992); F. Bosch et al., Phys. Rev. Lett. 77, 5190 (1996); K. Takahashi et al., At. Data N ucl. Data T ables 36, 375 (1987); C. B ertulani, Nucl.Phys.A 626, 187 (1997); M.Jung, et al, Phys. Rev. Lett.69, 2164 (1992); Yu. Litvinov et al, Phys. Lett. B573, 80 (2003). [2] A.V.Glushkov, L.N.Ivanov, P hys.Lett.A. 170, 36 ( 1992); A.V.Glushkov et al, Nucl. Phys. A734, e21 (2004); J.Phys.CS 35,420 ( 2006); Advances i n t he T heory of Atomic a nd Molecular S ystems: Dynamics, S pectroscopy, C lusters, a nd Nanostructures. Series: Progress in Theoretical Chemistry and Physics, E ds. P iecuch P ., M aruani J ., D elgado-Barrio G., Wilson S. (Berlin, Springer), 20, 125-172 (2009).
QED PERTURBATION THEORY
CALCULATING NUCLEAR QUADRUPOLE
MOMENTS AND HYPERFINE STRUCTURE
PARAMETERS FOR LI-LIKE
MULRICHARGED IONS
O.Yu. Khetselius*, A.A. Svinarenko, Yu.V. Dubrovskaya,
I.N. Serga, N.V. Mudraya
Odessa University, PO.Box 24a, Odessa-9, 65009, SE, Ukraine *E-mail: nuclei08@mail.ru
Relativistic calculation of the spectra, hyperfine structure (hfs) parameters f or he avy atoms a nd m ulticharged i ons w ith account of relativistic, correlation, nuclear, QED effects [1,2] is carried out . M ethod i s ba sed on t he g auge-invariant Q ED perturbation theory and generalized dynamical n uclear m odel [1]. T he F ermi m odel ha s b een us ed for modelling t he distribution of c harge i n a nuc leus. T he r esults of t he t est calculation of the hyperfine structure parameters for Н-like ion with nuclear cha rge Z=170 ( plus de rivatives of e nergy contributions on nuc lear radius) are presented. A contribution of the relativistic, nuclear and radiative corrections is definitive one f or H -like ion with Z=170. C alculation of t he hfs parameters, splitting energies, constants (plus derivatives from energy c ontributions, t he nuc lear electric a nd va cuum-polarization potentials on nuclear radius) for Li-like ions with Z=20-100 is carried out. It i s c arried out an an alysis of t he inter-electron correlations, nuclear, r adiative ef fects contributions, i ncluding a n a nalysis of t he r ole f or nuclear effects contribution (core-polarization ones, which are induced by va lent pr otons of a nuc leus), t emporal di stribution of
magnetization in a nucleus and high order QED corrections. As example t able 1 contains da ta on hfs pa rameters A=Z3
gI A , B= B I I Q Z ) 1 2 ( 3
− (cm-1 ) for some Li-like ions.
nlj/Z 41 59 69 79 92 3s A 32 –03 43 –03 51 –03 63 –03 90 –03 4s A 14 –03 16 –03 19 –03 24 –03 36 –03 2p1/2 A 35 –03 46 –03 56 –03 71 –03 105 –02 3p1/2 A 09 –03 12 –03 16 –03 20 –03 31 –03 4p1/2 A 43–04 58 –04 72 –04 91 –04 11 –03 2p3/2 A 60 –04 65 –04 67 –04 71 –04 72 –04 B 11 –04 12 –04 13 –04 15 –04 17 –04 3p3/2 A 16 –04 18 –04 19 –04 21 –04 22 –04 B 41 –05 48 –05 51 –05 55–05 62 –05 4p3/2 A 77 –05 84 –05 89 –05 92 –05 10 –04 B 14 –05 18 –05 20 –05 22 –05 26 –05
[1] A .V.Glushkov, JETP L ett. 55,108 (1992), A .V.Glushkov, L.N.Ivanov, Phys.Lett.A. 170, 36 (1992); A.V.Glushkov, E.P. Ivanova, J .Quant. S pectr. R ad. T r. ( US) 36,127 ( 1986); E.Ivanova, L.N.Ivanov, A.V.Glushkov, A.S.Kramida, Phys.Scr.
32, 512 ( 1985); A .V.Glushkov, In: Low E nergy Antiproton
Phys. (AIP Serie) 796, 211 (2005) ; J.Phys.CS. 11,199 (2005); References
[2] A ..Glushkov, O .Khetselius e tal, N ucl. P hys.A. 734, e 21 (2004); P hys.CS. 35, 42 5 ( 2006); A . G lushkov etal, R ecent Advances i n T heory of Phys. a nd C hem. S ystems, e dited J .-P.Julien, J. M aruani, D .Mayuo, S .Wilson, G .Delgado-Barrio (Springer) 15, 301 (2006); Ibid. 15, 285 (2006).
LASER SPECTROSCOPY OF THE
(1s
22s2p)
3P
0–
3
P
1LEVEL SPLITTING
IN BE-LIKE KRYPTON
Danyal Winters1,2, Th. Kühl1,3, D. Schneider4, P. Indelicato5,
R. Reuschl5, R. Schuch6, E. Lindroth6 and Th. Stöhlker1,2,7 1 GSI Darmstadt, Germany
2 Heidelberg University, Germany 3 Mainz University, Germany
4 Lawrence Livermore National Laboratory, USA 5 Laboratoire Kastler Brossel, Paris, France
6 Stockholm University, Sweden 7 Helmholtz Institute Jena, Germany
Heavy few-electron ions, such as He-, Li-, and Be-like ions, are ideal atomic s ystems to study e ffects of correlation, relativity and quantum electrodynamics [1-4]. Very recently, theoretical and experimental s tudies of t hese s pecies achi eved a considerable i mprovement i n a ccuracy. T he B e-like i ons a re interesting because their first excited state, i.e. the (1s22s2p) 3P0,
has an almost infinite lifetime in the absence of nuclear spin (I), as i t can only de cay b y a t wo-photon E1M1 transition to the (1s22s2) 1S0 ground s tate [5]. If t here i s nu clear s pin, t he
corresponding hyperfine structure will reduce th is lifetime b y orders of m agnitude. In addition, t he e nergy di fference between the 3P
0 and the 3P1 states i s ex pected to be al most
completely un affected by Q ED effects, and i s t herefore dominated by the effects of correlation and relativity [6]. We want to determine the (1s22s2p) 3P
0 - 3P1 level splitting in
Be-like krypton (84Kr32+), which ha s I=0, b y m eans of l aser spectroscopy at t he e xperimental s torage ring at G SI,
Darmstadt. In such an experiment, the energy splitting can be obtained w ith ve ry good a ccuracy, i.e. of t he o rder of ~10-5, and be compared with recent calculations [6].
References
[1] H. Persson et al., Phys. Rev. Lett. 76, 204 (1996) [2] W.R. Johnson et al., Phys. Rev. A51, 297 (1995) [3] P. Beiersdorfer et al., Phys. Rev. A52, 2693 (1995) [4] R. Marrs et al., Phys. Rev. A52, 3577 (1995) [5] J.P. Marques et al., Phys. Rev. A47, 929 (1993) [6] P. Indelicato, using the 2010 version of MCDFGME (a MultiConfiguration Dirac Fock and General Matrix Elements program, http://dirac.spectro.jussieu.fr/mcdf )
X-RAY SPECTROSCOPY OF COLLISIONS
BETWEEN HIGHLY-CHARGED IONS
AND H
2CLUSTERS
Natalya Winters1,2, H.F. Beyer1,3, W. Chen1, R.D. DuBois1,4,
R.E. Grisenti1,5, T. Gross1,2, A. Gumberidze1,4, S. Hagmann1,5,
M. Hegewald1,5, S. Hess1,5, P.M. Hillenbrand1,6,
C. Kozhuharov1, R. Märtin1,2, N. Petridis1,5, M. Schwemlein1,2, U. Spillmann1, D.B. Thorn1,4, S. Trotsenko1,3, G. Weber1,2,
D.F.A. Winters1,2, Z. Yin1,2 and Th. Stöhlker1,2,3 1 GSI Darmstadt, Germany
2 Heidelberg University, Germany 3 Helmholtz Institute Jena, Germany 4 ExtreMe Matter Institute, Darmstadt, Germany
5 Frankfurt University, Germany 6 Gießen University, Germany
We pe rformed x-ray s pectroscopy o f c ollisions be tween highly-charged ions and H2 clusters at the ESR storage ring of
GSI. These c ollisions w ere chosen to oc cur at relatively l ow kinetic ene rgies of some t ens of M eV/u, and at various H2
target de nsities, i.e. average d ensities between 1012 and 1014
atoms/cm2. At l ow ene rgies, the cr oss-section f or electron capture (i.e. REC and NRC) of target electrons by the projectile is much larger than at high energies [1]. At high target densities, a projectile ion could have multiple interactions with a target (cluster) [2]. The chosen collision scenario might the n be appropriate to l ook at I) t he transition from the single- to t he multiple-collision regime, and II) single- and multiple-electron capture processes. Two ex periments w ere pe rformed at t he internal target of the ESR to look for such effects.
In the first experiment, which took place in March 2009, bare r uthenium i ons ( Ru44+) collided with H2 at an energy of
~10 MeV/u. The H2 target was generated by a novel cryogenic
cluster s ource t hat cr eated an average t arget ar ea-density of 5x1012 atoms/cm2. At this density the jet produces (~30 nm size) clusters of atoms rather than molecules [2].
In March 2010 a s econd E SR e xperiment w as performed, us ing H -like kr ypton i ons (Kr35+) at an energy o f ~30 MeV/u. The average H2 target density was varied between
1012 and 10 14 atoms/cm2. These t wo experiments w ith H 2
aimed for e ffects f rom mul tiple c ollisions ( case I). However, with the h ydrogen target mul tiple-electron capture ( case II) cannot be studied. Therefore, we also used nitrogen and argon gas as a target.
We w ill pr esent and di scuss the ( preliminary) results obtained from both ESR experiments.
References
[1] J. Eichler and Th. Stöhlker, Phys. Rep. 439, 1 (2007). [2] M. Kühnle, N. Petridis, R.E. Grisenti, et al., Nucl. Instr. Meth. Phys. Res. A 602, 311 (2009).
PRECISION LASER SPECTROSCOPY OF
TRAPPED HIGHLY CHARGED IONS
Z. Andjelkovic1,2, S. Bharadia2,3, S. Stahl4, R. Thompson3, M.
Vogel3, W. Nörtershäuser1,2 and the HITRAP collaboration2
1
Mainz University, Germany; 2GSI Darmstadt, Germany;
3
Imperial College London, United Kingdom; 4Stahl Electronics, Mettenheim, Germany
The extremely strong fields that exist around the nuclei of few-electron heavy ions drastically change the properties of the electronic system such as energy level spacings, lifetimes and magnetic moments. In turn, the electrons serve as sensitive probes for nuclear properties such as size, magnetic moment and spatial distribution of charge and magnetization. The energies of their forbidden fine and hyperfine structure transitions strongly depend on the nuclear charge and shift from microwave domains in or close to the optical domain [1] [2]. Thus, they become accessible for laser spectroscopy and its potentially high precision. A number of such measurements have been performed in storage rings [3] [4] and electron beam ion traps [5], and have yielded results with relative accuracies in the permille region. We present here an experiment under development at GSI Darmstadt which aims to significantly increase the accuracy by employing charged particle traps which allow to slow the ion motion nearly to rest, thus reducing Doppler effects and increasing the possible accuracy to the more than ppm region [6].
References:
1. Shabaev, V.M.: J. Phys. B: At. Mol. Opt. Phys. 27, 5825 (1994)
2. Safronova, M.S., Johnson, W.R., Safronova, U.I.: Phys. Rev. A 54, 2850 (1996)
3. Klaft, I. et al.: Phys. Rev. Lett. 73, 18, 2425 (1994) 4. Seelig, P. et al.: Phys. Rev. Lett. 81, 22, 4824 (1998)
5. Crespo Lopez-Urrutia, J.R. et al.: Phys. Scr. T80, 448 (1999)
HIGHER-ORDER RESONANT INTER-SHELL
ELECTRONIC RECOMBINATION FOR
HEAVY HIGHLY CHARGED IONS
C. Beilmann, J.R.Crespo Lopez-Urrutia, S. Bernitt, Z. Harman, P.H.Mokler, J. Ullrich
Max-Planck-Institut f. Kernphysik, 69117 Heidelberg, Germany
Inter-shell Tri-electronic Recombination (TR) with K-shell ex-citation (cf. [1]) is reported for Li- to N-like ions of Ar, Fe, and Kr. Simultaneously to the K-shell excitation, an additional L electron is excited at recombination of a free electron, here also to the L shell: KL-LLL TR processes. Even clear indications on Quadru-electronic Recombination (QR) have been found, where one K electron and two additional L electrons are simultaneously excited during recombination with a free electron: KLL-LLLL QR processes. The highly charged ions (HCI) have been pro-duced and trapped in an EBIT and recombination with electrons is detected via the emitted resonant x-rays. Using a forced evap-orative cooling technique, high-resolution electronic recombina-tion spectra could be achieved - a prerequisite for observing the higher-order recombination processes.
The method significantly improving the energy resolution for resonant recombination measurements in an EBIT will be de-scribed. This forced evaporative cooling technique does not rely on a reduction of the primary electron beam current as previ-ously done. Hence, it provides abundant cooled ions for mea-surements. Typically an order of magnitude improvement in res-olution, and hence in sensitivity, is achieved. Results on
first-and higher-order recombination processes along iso-electronic sequences are reported. Special emphasis is given to the C-like sequence. Higher-order processes increase considerably with decreasing atomic number Z. At lower Z, the electron-electron correlation effects are more dominant; in some cases TR is even overwhelming the first-order dielectronic recombination process, a phenomenon truly relevant for plasma-related considerations. The higher-order recombination processes, their strength and rel-evance are discussed in the light of theoretical considerations. For the Be-like sequence no KL-LLL TR contributions are pre-dicted due to parity reasons. Indications for faint QR contribu-tions have been found for some iso-electronic sequences. *) P.Mokler@mpi-hd.mpg.de
References
DOUBLY EXCITED RESONANCE
1S
eAND
3P
eSTATES OF TWO ELECTRON ATOMS
Jayanta K Saha, S Bhattacharyya*and T K Mukherjee
Narula Institute of Technology, Agarpara, Kolkata 700 109 West Bengal, India
*Acharya Prafulla Chandra College, New Barackpore Kolkata 700 131, West Bengal, India
Stabilization m ethod [1] ha s be en s uccessfully employed i n order to calculate the resonance position and widths of 3Pe state of helium arising due to two electrons having same azimuthal quantum num ber be low di fferent i onization threshold of helium using extended Hylleraas basis set. The structure of the correlated wave function is taken from reference [2]. The non linear parameters of the wave function are taken in geometrical sequence [3] . T he energy eigenvalues are obtained by matrix diagonalisation procedure for different sets of geometrical ratio. All calculations are carried out in quadruple precession.
We have used 1575 parameters basis set wave function in order to construct the s tabilization plot(fig-I). T aking t he 25 th
eigenvalue from the stabilization plot in the interval γ = 1.74 to 1.79, w e ha ve calculated t he i nverse of t he slope or t he density of resonance s tates us ing t he f ormula t aken f rom reference [4]. This fitting procedure (fig-II) gives Er= -0.33618
a.u. a nd Γ = 0.00446 a .u. T he pr esent result i s i n g ood agreement with that of Ho and Bhatia [5]. It is worthwhile to mention t hat us ing t he s ame f itting pr ocedure w e f ind 2 2 resonance s tates of 3Pe below N = 3 t hreshold of he lium
whereas us ing c omplex-coordinate r otation m ethod H o a nd Bhatia [5] estimated the resonance parameters for 8 resonance states. Resonance pos itions a nd w idths of doubl y e xcited 1
resonance s tates o f t wo-electron atoms [ Z=3-10] be low N =2 hydrogenic threshold have also been studied using stabilization method. The pr esent resonance p arameters are i n excellent agreement with the available theoretical estimates. So in order to locate t he resonance pos ition and to calculate t he corresponding width, the present method may serve as a very useful one. 1.5 1.6 1.7 1.8 1.9 2.0 -0.34 -0.32 -0.30 -0.28 -0.26 -E ( a. u. ) γ
Fig- I : Stabilization plot for the 3Pe states of He below
N=3 threshold. - 0 .3 7 - 0 .3 6 - 0 .3 5 - 0 .3 4 - 0 .3 3 - 0 .3 2 - 0 .3 1 - 0 .3 0 - 0 .2 9 0 2 4 6 8 1 0 Density E n e r g y ( a . u )
Fig-II:Calculated density (circles) and t he f itted Lorentzian ( solid line) c orresponding t o 3p2 (3Pe)
state of He References
[1] V. A. Mandelshtam, T.R.Ravuri and H.S.Taylor, Phys. Rev. Lett., 70, 1932, 1993
:
[2] T. K. Mukherjee and P. K. Mukherjee, Phys. Rev. A, 69, 064501, 2004
[3] M. Bylicki, J. Phys. B: At. Mol. Opt. Phys., 30, 189, 1997 [4] W.J.Pong and Y.K.Ho, J. Phys. B: At. Mol. Opt. Phys., 31,
2177, 1998
STABILIZATION METHOD FOR
UNDERSTANDING BOUND AND RESONANCE
STATES OF HELIUM
T. K. Mukherjee, Jayanta K. Saha, S. Bhattacharyya*
Narula Institute of Technology, Agarpara, Kolkata 700 109 West Bengal, India
*Acharya Prafulla Chandra College, New Barackpore Kolkata 700 131, West Bengal, India
On the basis of stability, doubly excited states can be classified into two general groups as autoionizing and non-autoionizing depending upon the angular momentum coupling scheme and parity conservation rule [1]. In spite of being embedded in the continuum above N = 1 threshold of He+, the 2pnp (1,3PP
e
) and
2pnd (1,3
Do) states are non-autoionizing under strict L-S coupling scheme but inclusion of the relativistic effect makes autoionization possible [2]. These non-autoionizing doubly excited states are referred as metastable bound states. We have explained the well-known metastable bound state characteristics of 2pnd (1,3Do) and 2pnp (3PeP) states from a
different angle by applying the state-of-the-art method proposed by Mandelshtam et. al.[3]. In the line of this interpretation the nature of 3dnf (1,3Do) state has been discussed.
1,3
Dstate of odd parity may originate from both pd and df configuration. The structure of the correlated wave function of 495 parameters for 1,3Do state due to pd and df configuration is taken from ref.[4]. The non linear parameters (ρ) of the wave function is taken in geometrical sequence [5] .The energy eigenvalues are obtained by matrix diagonalization procedure for different sets of geometrical ratio. The estimation of density of resonance states and corresponding resonance parameters
from the stabilization plot are given by Saha and Mukherjee [6] where detailed investigation was done for 3PP
e
states of helium. A portion of stabilization diagram for 1Do state due to df configuration below N 3 threshold of He+ is given in fig-1. Horizontal lines are being obtained in case of 3dnf (1Do) states which confirms that these states are metastable bound states embedded in the continumm.
1.30 1.32 1.34 1.36 1.38 1.40 1.42 1.44 1.46 1.48 1.50 1.52 1.54 1.56 1.58 1.60 1.62 1.64 1.66 1.68 1.70 -0.270 -0.268 -0.266 -0.264 -0.262 -0.260 -0.258 -0.256 -0.254 -0.252 -0.250 -0.248 -0.246 -0.244 -0.242 -0.240 -0.238 -0.236 -0.234 -0.232 -0.230 -0.228 -0.226 -0.224 -0.22222 E nerg y ( a .u. ) γ
Fig.1: Stabilization diagram for 1Do states of helium due to df
configuration. References:
[1] G. W. F. Drake and A. Dalgarno, Phys. Rev. A 1, 1325(1970).
[2] E. Holoien, Nucl. Instrum. Meth. 90, 229 (1970) and references therein.
[3] V. A. Mandelshtam, T. R. Ravuri and H. S. Taylor, Phys. Rev. Lett. 70, 1932(1993).
[4] S. Bhattacharyya, A. N. Sil, T. K. Mukherjee and P. K. Mukherjee, J. Chem. Phys. 126 011104(2007).
[5] M. Bylicki, J. Phys. B 30, 189(1997).
[6] J. K. Saha and T. K. Mukherjee, Phys. Rev. A 80, 022513(2009) and references therein.
EFFECT OF DEBYE PLASMA ON
TRANSITION WAVELENGTH BETWEEN
DOUBLY EXCITED STATES OF
TWO-ELECTRON IONS
S Bhattacharyya*, Jayanta K. Saha, T K Mukherjee
Narula Institute of Technology, Agarpara, Kolkata 700 109 West Bengal, India
*Acharya Prafulla Chandra College, New Barackpore Kolkata 700 131, West Bengal, India
Interest in accurate atomic data for the helium atom embedded in different plasma e nvironments [ 1] a rises f rom the he lium abundances i n a strophysical pl asmas [ 2] a nd f rom t he production of helium-like laser plasmas in the laboratory [3]. In the pr esent w ork, t he Debye m odel ha s be en em ployed to include the effect of weakly coupled plasma background on the energy levels of the doubly excited states of two electron atoms [Z=2-4] as it is the most w ell know n a mong a ll t he approximate s tatic m odels w here t he effect o f s tatic pl asma screening i s t aken into account. The advantage of t he D ebye model lies in the fact that the screening constant is a function of t emperature and plasma de nsity and a v ariety of pl asma conditions can be simulated by changing the screening constant. The non-relativistic energy eigenvalues of doubly excited 2pnp (1Pe) [ n=3-8], 2pnp (3Pe) [ n=2-7] and 2pnd (1,3Do) [ n =3-6] metastable bound states of t wo electron atoms [ Z=2-4] are estimated under w eakly coupled pl asma screening using explicitly cor related Hylleraas t ype basis in the framework of Rayleigh-Ritz va riational pr inciple. It i s obs erved t hat the
system t ends t owards gr adual i nstability and t he num ber o f bound states reduces with increasing plasma coupling strength. The wavelengths for 2pnp (1Pe) [n=3-8] → 2pnd (1Do) [n=3-6] and 2pnp (3Pe) [ n=2-8]→2pnd (3Do) [ n=3-6] t ransitions i n
plasma embedded two electron atoms have also been estimated. The present calculated results show a general trend of the red shifting of th e tr ansition w avelengths with increasing pl asma screening effect. H owever, occasionally at some s pecific values of the Debye screening parameter a blue shifting of the transition wavelength is observed. This is possibly due to the difference of the effect of Debye screening on different angular momentum states [4]. 0.0 0.1 0.2 0.3 0.4 -0.8 -0.7 -0.6 -0.5 -0.4 -0.3 -0.2 -0.1 0.0 He2+ (2p) 2p2 (3 pe ) 2p3p(3 pe ) 2p4p(3 pe ) 2p5p(3 pe ) 2p6p(3 pe ) 2p7p(3 pe ) E ner gy (a. u. ) µ
Fig.1: Modified energy
values of 2pnp(3Pe) of He [n=2-8] versus Debye parameter. 0.00 0.010.02 0.03 0.04 0.05 0.06 0.07 0.08 0.090.10 -0.60 -0.58 -0.56 -0.54 -0.52 -0.50 -0.48 -0.46 -0.44 -0.42 -0.40 -0.38 -0.36 -0.34 -0.32 -0.30 He+(2p) 2p3d (3 Do ) 2p4d (3Do) 2p5d (3 Do ) 2p6d (3 Do ) Ener gy (a. u. ) µ
Fig.2 : Modified energy values of 2pnd(3Do) of
He [n=3-6] versus Debye parameter. References
1) S Kar and Y K Ho, J. Phys. B, At. Mol. Opt. Phys. 40 1403 (2007)
:
2) D Leckrone and J Sugar, Phys. Scr. T 47 (1993) 3) S Nakai and K Mima, Rep. Prog. Phys. 67 321 (2004) 4) J P Connerade, V K Dalmatov and P A Lakshmi, J. Phys.
DESIGN AND MANUFACTURE A
CATHODOLUMINESCENCE INSTRUMENT
FOR MATERIAL CHARACTERIZATION
Yousefi, Elham, Shafiekhani, Azizollah*
Carbon Research Laboratory, Alzahra University, Tehran, Iran (*) Physics Department, Alzahra University, Tehran, Iran The ai m o f thi s s tudy is to make a nd test the Cathodoluminescence i nstrument ( CL) as a no n-destructive tester for analyzing and characterizing material.
CL has a capacity o f 2 l itres and has s pecial geometry f or installation of electron gun, s ample, s pectrometer op tic fibre, vacuum gages a nd va cuum pumps. For increasing t he m ean free path of electrons, the pressure of CL decreases to 10-6 torr,
by r otary and diffusion pum ps. E lectron g un emits electrons and accelerates them to the sample as a target. Electrons impact the s ample and due t o t his ha ppening, some di fferent phenomena occur l ike: X-ray, s econdary and b ackscattering electrons, a uger e lectrons, vi sible l ight, ul traviolet a nd ne ar infrared lights. T he three l ast phe nomena are called Cathodoluminescence. By using spectrometer EPP2000 which is capa ble of detect ul traviolet-visible-near i nfrared e mission; the emission spectrum can be obtained by an intensity diagram vs. wavelength. The elements of m aterial and respect am ount of ea ch are obt ained b y t he an alysis of t his s pectrum. At t he first measuring, the pure material like copper, aluminium and iron are studied. These spectrums ar e completely compatible with the r egistered spectra obtained b y ot her ways. Further projects will be on complex and nano material
The advantage of this CL is simplicity, accuracy and low cost. This CL is also the first one in Iran.
References
[1] J. Gotze, “ Potential of C athodoluminescence ( CL) Microscopy and Spectroscopy for the Analysis of Minerals and Materials”, Anal Bional Chem., (2002)
[2] http://physics.nist.gov/cgi-bin/ASD/lines1.pl
[3] B. G . Y acobi, “Cathodoluminescence Microscopy of Inorganic Solids”, Plenum Press, New York, (1990)
Experimental studies of X-ray from H- and He-like
highly charge argon ions
Y. Zhao1*, X. Zhang1, 2, O. Rosmej3, J. Rzadkiewicz4,
Y. Wang1, X. Wang1,5, Z. Yang1, X. Chen6, F. Li5, G. Xiao1
1. Institute of Modern Physics,CAS, Lanzhou, China 730000 2. Xianyang Normal University, Xianyang, China 712000
3. GSI, Darmstadt, Germany 64591 4. IPJ Swierk, Poland 87545
5. Xi’an Jiaotong University, Xi’an, China 710049 6. Lanzhou University, Lanzhou, China 730000
(*) zhaoyt@impcas.ac.cn
X ra ys from H - and H e-like hi ghly charged a rgon i ons w ere investigated in recent f ew years both on t he E CRIS a t IMP-Lanzhou a nd on t he hi gh pow er Z-pinch machine at IP J, Warsaw. The S i(Li) de tector and FSSR(Focus Spectrometer with Spatial Resolution) w as us ed i n t he e xperiments respectively. The results are compared and discussed, and the future e xperiments a bout t his t opic on t he S uper-conductive ECRIS at IMP-Lanzhou are introduced.
References
[1] Y. Zhao, G. Xiao, and X. Zhang et.al, NIM B258, 1 (2007) [2] J. Abdallah 86 Jr et al. Journal of Quantitative Spectroscopy & Radiative Transfer 62 (1999)
A pulsed supersonic gas jet target for
experiments at the HITRAP facility*
K. E. Stiebing, D.F.A. Winters1,2, W. Quint†1,2, V.
Varentsov†1,3, A. Warczak†4, and Th. Stöhlker1,2,5
Institute of Nuclear Physics, Goethe University Frankfurt am Main, Germany
1GSI Darmstadt, Germany; 2Heidelberg University, Germany; 3ITEP, Moscow, Russia; 4Jagiellonian University, Krakow,
Poland; 5Helmholtz Institute Jena, Germany;
The heavy ion trap facility (HITRAP) at GSI, Darmstadt, offers unique possibilities to perform experiments with slow very highly charge heavy ions and opens new frontiers to tests of theories of atomic physics in very high fields and complex atomic structures.
In order to provide a common experimental basis for such experiments at the external beam of HITRAP, a novel gas target was designed in the frame of an INTAS cooperation† and
is presently under construction. By utilizing the time structure of ion bunches extracted from HITRAP, this new target is distinguished from other installations by a comparatively compact design, while it nevertheless provides sufficient pumping power to be operated at a VUHV beam line, essential for experiments with very heavy HCI’s up to e.g. U92+.
For most of the planned experiments, the cross-sections are fairly large (e.g. ~10−13 cm2 for electron capture) demanding for target densities of the order of 1011 atoms/cm2, which can
easily be achieved. The supersonic jet target consists of two expansion stages (with skimmers) providing a sufficiently localized jet in the interaction chamber. The jet is then funneled into a jet dump. The interaction chamber will be supplied with ports for launching different types of x-ray detectors under defined observation angles at maximized solid angles.
The first expansion stage will be pumped via a three-stage roots-pump system combined with a rotary vane pump at the point of exhaust. All other stages and beam lines entering and leaving the target area are pumped via turbo-pumps (500 l/s), selected for highest compressions for effective pumping of H2,
which will be one of the working gases, most frequently used. The design of the setup is compact, robust, and modular, so that, besides the above multi purpose chamber for x-ray measurements, specially designed collision chambers can be mounted as well. The residual gas pressure in the beam line is expected to be 10−10 mbar or better when the target is under operation. The design of the vacuum system will be finalized in the first half of 2010. Assembly of the gas target will be started after delivery of the elements of the vacuum recipient, in the second half of 2010.
BRANCHING RATIOS OF X-RAY PHOTONS
IN HE-LIKE IONS
Kadrekar Riddhi and L.Natarajan Department of Physics, University of Mumbai,
Mumbai-400098, India.
He-like i ons pr ovide t he m ost i mportant X -ray s pectral diagnostics i n hi gh t emperature f usion a nd astrophysical plasmas. In this w ork, l arge s cale calculations on t he various possible radiative transitions from He-like Ti and Fe i ons w ith 2p2 and 2s 2p c onfigurations de caying
sequentially to the ground state have been carried out. The transition parameters h ave been calculated using m ulti-configuration Dirac-Fock wavefunctions with the inclusion of Breit interaction and quantum electrodynamic effects [1]. The c orrelation c ontributions have be en evaluated in the active s pace approximation. The br anching ratios ar e compared with available experimental data [2].
This w ork w as s upported b y t he pr oject f inanced b y t he Department of S cience a nd T echnology, G overnment of India, India.
References
[1] P.Jonsson et al.,Comput. Phys. Commun. 177, 597 (2007) .
Accurate spectroscopy of excited levels in He-like
uranium
M. Trassinelli1, A. Kumar2, H.F. Beyer3, P. Indelicato4, R. M¨artin3,5, R. Reuschl1 , Y.S. Kozhedub6 , C. Brandau3 , H. Br¨auning3 , S. Geyer3 , A. Gumberidze7 , S. Hess3 , P. Jagodzinski8 , C. Kozhuharov3 , D. Liesen3 , U. Spillmann3 , S. Trotsenko9
, G. Weber3,5, D.F.A. Winters3,5, Th. St¨ohlker3,5,9
(1) Institut des NanoSciences de Paris; CNRS; Univ. Pierre et Marie Curie - Paris 6, Paris, France
(2) Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai, India
(3) GSI Helmholtzzentrum f¨ur Schwerionenforschung GmbH, Darmstadt, Germany
(4) Laboratoire Kastler Brossel, ´Ecole Normale Sup´erieure; CNRS; Univ. Pierre et Marie Curie - Paris 6, Paris, France
(5) Physikalisches Institut, Univ. Heidelberg, Heidelberg, Germany
(6) Department of Physics, St. Petersburg State Univ., St. Petersburg, Russia
(7) ExtreMe Matter Institue, Darmstadt, Germany (8) Institute of Physics, Jan Kochanowski Univ., Kielce, Poland
(9) Helmholtz-Institut Jena, Jena, Germany
Heliumlike heavy ion spectroscopy represents an unique probe of relativistic and Quantum Electrodynamics effects on the electron-electron interaction in the domain of strong fields. As com-pared to a one-electron and many-electron ions, these ions are
the simplest multibody systems where theory can make predic-tions in a rigorous way. Here we present the first clear identifi-cation and highly accurate measurement of the intra-shell tran-sition 1s2p3
P2 → 1s2s3S1 of He-like uranium performed via
X-ray spectroscopy. The present experiment has been conducted at the gas-jet target of the ESR storage ring in GSI (Darmstadt, Germany) where a Bragg spectrometer, with a bent germanium crystal, and a Ge(i) detector were mounted. Using the ESR de-celeration capabilities, we performed a differential measurement between the 1s2p3
P2 → 1s2s3S1 He-like U transition energy,
at 4510 eV, and the 1s22p 2P3/2 → 1s22s2S1/2 Li-like U
tran-sition energy, at 4460 eV. By a proper choice of the ion veloc-ities, the x-ray energies from the He- and Li-like ions could be measured, in the laboratory frame, at the same photon energy. This allowed for a drastic reduction of the experimental system-atic uncertainties, principally due to the Doppler effect, and for a comparison with the theory without the uncertainties arising from one-photon QED predictions and nuclear size corrections. The description of the experiment and the final result of the data analysis will be presented.
References
[1] M. Trassinelli et al., Eur. Phys. Lett. 87, 63001 (2009). [2] M. Trassinelli et al., J. Phys. CS 163, 012026 (2009).
