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Submitted on 1 Jan 1979
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PROJECT AND THE PRELIMINARY RESULTS OF THE EXPERIMENTS ON THE 57Fe MÖSSBAUER
LEVEL EXCITATION USING SYNCHROTRON RADIATION
A. Artemiev, V. Kabannik, Y. Kazakov, G. Kulipanov, E. Meleshko, V.
Sklyarevskii, A. Strinsky, E. Stepanov, V. Klestov, A. Chechin
To cite this version:
A. Artemiev, V. Kabannik, Y. Kazakov, G. Kulipanov, E. Meleshko, et al.. PROJECT AND THE
PRELIMINARY RESULTS OF THE EXPERIMENTS ON THE 57Fe MÖSSBAUER LEVEL EX-
CITATION USING SYNCHROTRON RADIATION. Journal de Physique Colloques, 1979, 40 (C2),
pp.C2-23-C2-25. �10.1051/jphyscol:1979206�. �jpa-00218464�
JOURNAL DE PHYSIQUE Colloque C2, suppl6ment au n O 3, Tome 40, mars 1979, page C2-23
PROJECT AND THE PRELIMINARY RESULTS OF THE EXPERIMENTS ON THE 5 7 ~ e M ~ S S B A U E R LEVEL E X C I T A T I O N USING SYNCHROTRON RADIATION
A.N. Artemiev, V.A. Kabannik, Y. Kazakov, G.N. Kulipanov, E.A. Meleshko, V.V. Sklyarevskii, A.N. Strinsky, E.P. Stepanov, V.B. Klestov and A.I. Chechin.
I n s t i t u t e of Nuclear, Physics, Novosibirsk and Kurchatov Atomic Energy I n s t i t u t e , U.S.S.B.
R6sum6.- Un dispositif expsrimental est propos6 pour rLaliser des expgriences de r6solution en temps.
Abstract. An experimental arrangement is proposed for the performance of time resolution experiments.
The properties of SR give rise to the possibi- lity of a direct excitation of Mijssbauer levels and an investigation of the resonant diffraction time dependence. To perform such experiments without SR one has to design an ultra-rapid chopper and a su- per intense source. So SR brightness amounts to-10"
phot ./cm2. s.sterp~ of rnat of
57~e7
while O.1ci/m2 source gives 2x10' phot. /cm2s .ster.Chopping will reduce the mean brightness of the sour- ce by a factor 10'. In contrast to that the SR time distribution E n s pulses spaced by fortunately suits experiments (1)
.
The work was carried out on a VEPP-3 storage ring Ee=2.2 GeV,Ie= 100
4.
The monochromator (Fig. 1) consists of two perfect Ge crystals set in a highly dispersive position.Fig. 1 : Layout of the experiment on 5 7 ~ e Mgssbauer level excitation by SR.
("other possible application of SR are discussed / I ,2/.
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1979206
C2-24 JOURNAL DE PHYSIQUE
A hematite a-57~e203 single crystal was positioned for purely nuclear Bragg reflection 131. Pure nu- clear Bragg reflection suppressed coherent electron scattering by factor of
lo5
oz even more. Moreover, the high degree of SR polarization (90%) and the an- gle of scattering by a-57~e203 (which is near 90') suppressed coherent and incoherent background scat- tering, too.The monochromator stability on the SR was checked with the help of a 3rd Ge single crystal re- placing the a -"Fe203 on the goniometer. We varied the storage ring current up to 25 mA. The persisten- ce of the measured 3rd crystal rocking curve posi- tion gave evidence of the stability in the monochro- mator energy transmission band. The linear increase in the intensity indicates the persistance of re- flectance of the Ge crystals.
We have measured the c%-'~F~zo~ rocking curves for E =2.0 GeV, I =IOmA in the (666) reflection and obetained Icohe=6.6x10*/s (1:Zic=4 .3x105/s). In the
exp
vicinity of pure nuclear reflection (777) there was mpeak. To clear up the nature of background in the last case we measured amplitude spectra (Fig. 2). A strong (666) reflection spectrum consists of a sin- gle 14.4 keV peak. The coherent peak in the (888) reflection is considerably suppressed because of the high degree of SR polarization and because the angle of scattering of the (888) reflection is near 90'.
Therefore X-ray peak (E=6.3keV) of 5 7 ~ e presents in the spectra. There is practically only X-ray peak in the amplitude spectrum in the vicinity of (777) re- flection. After electronic discrimination of this peak we have got 1~'~(777)=0.3/s (Icalc(777)=3/s). coh
exp
Electronics comprises a reference pulse former, detection channel time to amplitude convector and amplitude analyzer /5/ Time measurements were car- ried out with a-57~e203 (444) feable reflection (Fig. 3)
.
tune, n s
Fig. 3 : The time distribution of scattered quanta on the NaI(T1) detector
Fig.2 : The energy (amplitude) spectra of the allo- wed (666) and (888) reflections and in the vicinity of the forbidden (777) one.
The instantaneous diffraction peak width is 911s.
Peak to background ratio is 1 .7x103.
So the major difficulty in Mijssbauer experi- ments with SR appears to have been overcome. The conditions are found at which the background resul- ting from instantaneous electronic diffraction of the huge SR flux is suppressed.
References
/I/ Kulipanov, G.N. and Skrinsky, A.N., Sov.Phys.
Uspekhi
122
( 1977) 369./2/ Synchrotron radiation research, SSRP Report (1976) 76-100.
131 Stepanov, E.P., Artemiev, A.N. et al. JETP
3
(1974) 1150.
/4/ Kagan, Yu. Afanasyev, A.M., JEPT
50
(1966) 271 151 Meleshko, E.A., Morozov, A.G., PTE1
(1977) 141 161 Budker, G.I. et al. Report at the SatelliteMeeting after SR Instrument and Development, Orsay, France ( 1 977).
