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if the axions or other axion - like pseudoscalar particles couple with electrons then they are emitted from sun by the compton process and by bremsstrahlung @xcite-@xcite .
the expected spectrum of axions was calculated using theoretical predictions for the compton cross section given in @xcite and the axion bremsstrahlung due to electron - nucleus collisions given in @xcite .
the axion flux is determined for radial distribution of the temperature , density of electrons and nuclei given by bs05(op ) standard solar model @xcite based on high - z abundances @xcite .
the results of our calculations presented in fig.[fig1.eps ] @xcite .    as a pseudoscalar particle
, the axion should be subject to resonant absorption and emission in the nuclear transitions of a magnetic type . in our experiment
we have chosen the @xmath0tm nucleus as a target .
the energy of the first nuclear level ( 3/2@xmath10 ) is equal to 8.41 kev , the total axion flux at this energy is @xmath11 .
the 8.41 kev nuclear level discharges through @xmath12-type transition with @xmath13-transition admixture value of @xmath14=0.11% and the relative probability of @xmath15-ray emission is @xmath16 @xcite .
the cross - section for the resonant absorption of the axions with energy @xmath17 is given by the expression that is similar to the one for @xmath15-ray resonant absorption , but the ratio of the nuclear transition probability with the emission of an axion @xmath18 to the probability of magnetic type transition @xmath19 has to be taken into account @xcite . the @xmath20 ratio calculated in the long - wave approximation , depends on isoscalar @xmath21 and isovector @xmath22 coupling constants and parameters depending on the particular nuclear matrix elements @xcite .    as a result
the rate of axion absorption by @xmath0tm nucleus dependent only on the coupling constants is ( the model - independent view ) @xcite : @xmath23 using the relations between @xmath24 , @xmath25 and axion mass given by ksvz model , the absorption rate can be presented as a function of @xmath26 and axion mass @xmath27 ( @xmath27 in ev units ) : @xmath28    , @xmath29 ) @xcite .
3 - spectrum of the axions produced by primakoff effect ( @xmath30 ) .
the level scheme of @xmath0tm nucleus is shown in the inset @xcite.,scaledwidth=50.0% ]
if the mass of the axion is several kev , the expected solar axion spectra changes significantly and depends on the particular @xmath31 value @xcite . to calculate spectra we used the procedure similar described above .
the spectra of solar axions were determined for different values of @xmath31 @xcite .
an axion interacting with an electron should undergo axio - electric absorption , which is an analog of the photoelectric effect .
silicon atoms entering into the composition of a si(li ) detector were used in our experiment as targets for the axio - electric effect .
the cross section of the axioelectric absorption was calculated by the formula @xmath32 where @xmath33 is the cross section for the photoelectric effect and @xmath34 is the velocity of the axion . at @xmath35 1 and @xmath35 0 ,
this formula coincides with the cross sections for relativistic and nonrelativistic axions obtained in @xcite and provides an extrapolation approximately linear in @xmath36 , which ensures a sufficient accuracy for the case under consideration .
the energies of the gaussian peaks are given near them .
the expected spectrum is shown for the case of the detection of axions with @xmath37 kev and @xmath38.,scaledwidth=50.0% ]    the expected signal from 5 kev axions undergouing axioelctric effect in si - detector is shown in fig.[fig2.eps ] .
to search for quanta with an energy of 8.41kev due to axion resonant absorption , the planar si(li ) detector with a sensitive area diameter of 66 mm and a thickness of 5 mm was used .
the detector was mounted on 5 cm thick copper plate that protected the detector from the external radioactivity .
the detector and the holder were placed in a vacuum cryostat and cooled to liquid nitrogen temperatures .
a @xmath39 target of 2 g mass was uniformly deposited on a plexiglas substrate 70 mm in diameter at a distance of 1.5 mm from the detector surface .
external passive shielding composed of copper , iron and lead layers was adjusted to the cryostat and eliminated external radioactivity background by a factor of about 500 .    to search for axioelectric effect we used a si(li ) detector with a sensitive - region diameter of 17 mm and a thickness of 2.5 mm .
the detector was placed in a vacuum cryostat with the input beryllium window 20 @xmath40 m thick .
the window was used for energy calibration and determination of the detection efficiency of gamma - ray photons in order to find the sensitive volume of the detector .
the detector was surrounded by 12.5 cm of copper and 2.5 cm of lead , which reduced the background of the detector at an energy of 14 kev by a factor of 110 as compared to the unshielded detector .
the experimental setups were located on the ground surface .
events produced by cosmic rays and fast neutrons were registered by an active shielding consisting of five plastic scintillators @xmath41 cm in size .
the rate of 50 @xmath40s veto signals was 600 counts / s , that lead to @xmath42 3% dead time .
more details of experiments one can find in @xcite .    . the regions of excluded values lie above the corresponding lines .
the inclined lines show the @xmath26 values in the dfsz and ksvz ( @xmath43 ) models.,scaledwidth=50.0% ]
the upper limit on axions absorption rate by @xmath9 nucleus @xmath44 set by our experiment limits the possible values of coupling constants @xmath26 , @xmath45 and axion mass @xmath27 . according to ( [ rategamag0g3 ] ) and ( [ rategama ] ) and taking into account the approximate equality of the axion and @xmath15-quantum momenta @xmath46 for @xmath47 kev we obtain ( at 90% c.l . ) : @xmath48 @xmath49 the restriction ( [ lim1 ] ) is a model independent one on axion ( or any other pseudoscalar particle ) couplings with electron and nucleons .
the result ( [ lim2 ] ) presented as a restriction on the range of possible values of @xmath26 and @xmath27 ( ksvz relations between @xmath45 and @xmath27 are used ) allows one to compare our result ( fig.[fig3.eps ] , line 9 ) with results of other experiments restricting @xmath26 ( fig.[fig3.eps ] ) .
the limits on @xmath50 for dfsz axion lie in the range ( @xmath51 ) of the restriction .
as we mention in @xcite the sensitivity of experiment with @xmath9 can be increased significantly ( in @xmath52 times ) by introducing the tm target inside the sensitive volume of detector having high energy resolution , at present , cryogenic detectors have the best option .
when looking for the axioelectric effect the measured spectrum is fitted by the sum of an exponential function , describing the smooth background and the response function for axions @xmath53 : @xmath54 here , @xmath55 is the number of silicon atoms in the sensitive volume of the detector and @xmath56 is the live time of measurement .
the upper bound for @xmath57 at @xmath27=0 is @xmath58 at 90% c.l
. limit ( [ mainlimit ] ) is a model independent bound for the coupling constant of the axion or any other pseudoscalar relativistic particle with the electron .    for nonrelativistic axions
the fitting range was expanded to 16 kev . to describe the experimental spectrum in a wide range , function [ fit_a_e ]
was supplemented by a linear term for describing the continuous background and six gaussians for describing the peaks of the characteristic np x rays manifested in the measurements @xcite .
the fit results and @xmath53 for @xmath31 = 5 kev are shown in fig.[fig2.eps ] .
the maximum deviation of @xmath59 from zero for all tested ( from 1 to 10 kev with a step of 1 kev ) @xmath31 values is 2.5@xmath60 .
the upper bounds obtained for @xmath57 at various @xmath31 values are shown in fig.[fig3.eps ] ( line 1 ) in comparison with the other experimental results .
this work was supported by rfbr grants 13 - 02 - 01199-a and 13 - 02 - 12140-ofi - m .
the search for resonant absorption of compton and bremsstrahlung solar axions by @xmath0tm nuclei have been performed . 
 such an absorption should lead to the excitation of low - lying nuclear energy level : @xmath1tm @xmath2tm@xmath3 @xmath4tm @xmath5 ( 8.41 kev ) . 
 additionally the axio - electric effect in silicon atoms is sought . 
 the axions are detected using a si(li ) detectors placed in a low - background setup . as a result , a new model independent restrictions on the axion - electron and the axion - nucleon coupling : @xmath6 and the axion - electron coupling constant : @xmath7 has been obtained . 
 the limits leads to the bounds @xmath8 7.9 ev and @xmath8 1.3 kev for the mass of the axion in the dfsz and ksvz models , respectively ( 90% c.l . ) .