- Email: [email protected]
Application of accelerator in research of condensed lasants for nuclear pumped lasers
!h!lUMl B
Nuclear Instruments and Methods in Physics Research B 89 (1994) 412-415 North-Holland
Beam Interactions with Materials 8 Atoms
Application of accelerator in research of condensed lasants for nuclear pumped lasers E.A. Seregina *, P.P. D’yachenko, V.V. Kalinin Institute of Physics an Power Engineering, 249020 Obninsk, Russian Federation
A technique for measuring a conversion efficiency 7, a lifetime of working level 7 and the position and width of spectral lines of activator ions during excitation of media by nuclear reaction products is presented. The 14-MeV neutrons from the reaction 3H(d, nJ4He have been used for the homogeneous excitation of condensed lasants. The charged particles produced by the interaction of the fast neutrons react with the atomic nuclei of the medium. This technique has been tested on the laser crystal Y,AI,O,, : Nd3+ and has been used for the investigation of laser-active inorganic liquids.
1. Introduction
A problem of today is the search of laser-active media for nuclear pumped lasers (NPLs) [1,2]. To estimate the prospect of some lasant for NPLs it is necessary to know the efficiency of charged particles energy conversion to luminescence energy (conversion efficiency) 7, the lifetime of working level T and the position and width of spectral lines of activator ions during excitation of media by nuclear reaction products [3]. Laser-active inorganic liquids are of great interest as potential lasants for NPLs. However until recently only experimental data for laser crystals and glasses were available. The spectral-luminescence properties of these lasants were measured during excitation by different types of radiation such as X-rays [4-61, electrons [7] and heavy charged particles [8]. It should be mentioned that the high value of the interaction crosssections of all these types of ionizing radiation leads to an effective excitation of solid layers which are only about 0.01-0.1 cm below the surface. In general laseractive liquids are filled in quartz cells. For this reason it is very difficult to excite liquid lasant by short-run ionizing radiation. In order to obtain necessary information about liquid lasant properties the media should be placed into the beam of particles having large penetration capacity, namely into neutron field. In this case the homogeneous volume excitation of lasants is caused by the reaction of charged particles produced by the interaction of neutrons with the nuclei of the medium. * Corresponding author. + This work was supported, in part, by a Soros Humanitarian Foundations Grant awarded by the American Physical Society.
The technique of the investigation of spectralluminescent properties of condensed lasants placed in the beam of fast neutrons is described. This technique has been tested on the laser crystal Y,Al,O,, : Nd3+.
2. Experimental
method
The aim of the method is the measurement of two spontaneous photon emission distributions under the short multi-particle excitation of the active media with nuclear reaction products: the time distribution Qph(t) and the wavelength distribution P(A). The experiments have been carried out at the neutron generator KG-03 of IPPE. Fig. 1 shows the experimental setup. The neutron beam (E, = 14 MeV) was produced in 3H(d, n)4He reactions by a pulsed deuterium beam. The pulse width, frequency and average current on the target are 10 ps, 1 kHz and 2 FA, respectively. The neutrons were recorded by the detector based on a stilben crystal in combination with a photomultiplier FEU-13. The registration threshold was fixed at the value of 6 MeV. The count efficiency of the neutron detector was calculated by a Monte Carlo method using the program “Cristy” [9]. It was 1.9 * 0.2%. The investigated sample has been positioned near the neutron source. 14-MeV neutrons interact with the nuclei of almost all isotopes. The cross-sections of these reactions were measured with high accuracy [lo]. During a very short time charged particles appearing in result of neutron reactions such as A(n, b)B, transfer their energies to the medium and exciting activator ions. The luminescence photons of the sample travel through the quartz waveguides to the entrance slit of the monochromator MDR-23. The photomultiplier FEU-62 working as a photon detector and operating in
0168-583X/94/$07.00 0 1994 - Elsevier Science B.V. All rights reserved SSDI 016%583X(93)E0954-F
E.A. Seregina et al./Nucl. Instr. and Meth. in Phys. Res. B 89 (1994) 412-415
413
the measured photon counting rate n, to the photon numbers radiated by the tungsten lamp is the photon counting efficiency and can be written:
(1)
Fig. 1. Experimental setup. (1) Tritium target; (2) sample; (3) quartz waveguides; (4) neutron detector; (5) amplifier; (6) discriminator; (7) concrete wall; (8) monochromator; (9) photon detector; (10) delay line; (11) two entrance analyzer; (12) CAMAC crate controller; (13) PC.
the single-electron regime, was connected with the slit of the MDR-23. The photocathode of the FEU-62 was cooled by liquid nitrogen vapor to - 50°C. The count rate of phone pulses was lower than 1 s-l. It should be mentioned that the monochromator, the FEU-62 and the other electronic equipment are located in the measuring room shielded by concrete walls from the influence of the radiation. The measuring of the time distributions was carried out by use of a method similar to the well known “time-of-flight method”. The pulse from the target of the neutron generator produces a “start” signal for the registration of the medium excitation moment. Photon and neutron detectors produce “stop” signals. Through discriminators “start” and “stop” signals travel to the two-entrance analyzer of time intervals. The analyzer memory simultaneously stores data of two independent distributions: Qr&) and Q,(r). In addition the lifetime of the 4Fs,2 of Nd3+-ions upon flash lamp pumping was measured by the use of a pulse laser ILGI-503 (A, = 337 nm). The same technique as for measuring Q(t) was used to measure the photon wavelength distribution P(A) and the distribution of the neutron numbers from the generator target, which were directly proportional to the numbers of charged particles exciting the medium. For this purpose the two-entrance analyzer was switched to the multiscaling mode and the monochromator to the wavelength scanning mode. In a special experiment the photon detection efficiency has been measured. In this case a calibrated tungsten lamp served as the source of photons. Using a lens the image of the filament was projected by one-toone magnification into the center of the place, where the sample was located. The photon counting rate nh was measured in the multiscaling mode. The ratio of
where BA,T is the spectral brightness of the lamp’s radiation defined by the Plank formula, K* T the tungsten blackness constant, 6 the spectral width of the outlet slit of the monochromator, S the area of the tungsten filament, K the transmission of the optical system, R the solid angle within which the photons arrive at the collimator of the monochromator. The measurement shows that the value of e* changed from low4 to 10m6 in the wavelength range 340-1150 nm. The principal systematic error of the measuring of lA must be considered as the uncertainty in the calibration of the tungsten lamp. If the uncertainty in the determination of the tungsten filament temperature is It 25”C, the error in E* could be f 25% at A = 600 nm and f 15% at A = 1050 nm.
outlet
3. Results and discussion Time distributions Qr,Jt) were used to determine the lifetimes of excited activator ion levels. Figs. 2a and 2b show the instrumental distributions Q&) of Nd3+ luminescence photons for transitions from levels 2F25,2 (a) and 4F3,2 (b) to the lower levels. The time distribution of the number of neutrons from the KG-O.3 target are shown in this figure too (dashed line). The values of the lifetime calculated from Qr&) were 3.5 f 0.2 us and 210 f 15 ps for levels 2F25,.r and 4F3,2, respectively. The wavelength instrumental distributions of luminescence photons P(A,) are shown in Fig. 3. They were used for determining the absolute yield of photons. The instrumental distribution P(Ai) was treated in the 10
-
D
I---
a
channel
b
number
Fig. 2. Instrumental distributions Q$r) of Nd3+ luminescence photons for transitions of level F2s,, (a) and 4F3,2 (b) to the lower level. Width of the channel is 1 us. IX. MISCELLANEOUS
414
EA. Seregina et al. /Nucl.
Instr. and Meth. in Phys. Res. B 89 (1994) 412-415
following way: one should subtract the background, which was lower then 1 s-l. Then P(hi) was normalized by the average neutron numbers: -
P’(A,)
=fyA&
(2)
where i is the channel number, @ the average number of neutrons from the target, and N(i) the neutron number registered in channel i. Further we have calculated the total energy yield of photons per second in a defined wavelength region using the expression: Ak
Wph = 4PE,h A
c zho
Table 1 Lifetime of ‘F2,,, and 4F,,, levels and conversion efficiency of Nd3+-ions upon excitation by different types of radiation Type of radiation
7 (CL4
n (%)
2=
4F3,2
A(n, b1B
3.5+0.2
f, Q *
3.2+0.2
5/2
(3)
where hi is the wavelength related to channel i, R’(Ai) is the counting rate of photons with wavelength Ai, A = 1.335 nm the monochromator scanning step (width of channel), S the area of the entrance slit, 0 the solid angle, 6 the spectral width of the outlet slit of the MDR-23, L the length of the sample, E,, the mean energy of photons in interval A, - A,. The value of WE, the energy deposited by the nuclear reaction products at the stopping in the active medium, was calculated by a Monte Carlo method using the program “Brand” [ll]. This program code takes into consideration all available information about interaction of neutrons with a substance. The values of cross-sections and energies of nuclear reactions from ref. [lo] were used. These calculations show that the
a
210&15 2.15*0.
41,,2
this work
3.5+0.3 e3.02kO.l y-ray Flash lamp -
R'(h,)A
Sf.k( A,)SL ’
4F3,2
Ref. *4111,2,
215f20 2.0+0.4 180* 10 4.0+ 1.0
200+10 230*30
-
Bl [71 Kl this work
* 7 was measured under excitation by fission fragments of 252cf.
value of w0 (the energy deposition of nuclear reaction products for one neutron from the target) was 9.07 X
lo3 eV cm-3. In our experiment the average neutron flux from the target was 4, = (8.6 f 0.3) x lo8 n s-l. The rate of total energy deposition W, was equal to o,, 4, = 7.8 x 1012 eV cmW3 s-l. The total error in the W, determination was about f6%. It includes the statistic error of the Monte Carlo calculation (0.3%), the error of the neutron reaction cross-section determination (I 2%), the error of the atom concentration measurements (I 2%) and the error of the neutron number measurement (I 5%). Results of r and n measurements for excitation of Y,Al,O,, : Nd3+ by high energy radiation are listed in Table 1. One can see that the lifetimes of the 2F25,2 and 4F3,2 levels obtained in our work are in good agreement with results of other experiments. The conversion efficiency q was only measured in two previous works [7,8]. Here it should be noticed that the value of q measured in the present work is in good agreement with results obtained for excitation of Y Also,, : Nd3+ by o-particles and fission fragments of js2Cf [8].
4. Conclusions
channel
number
Fig. 3. (a) Instrumental distributions of luminescence photons, P&I, for transitions 4F,,, a419,* (1) and 4F3,2 =4I11,2 (2) “0’‘-channel corresponds to 850 nm, width of channel 1.3335 nm; (b) Instrumental distributions of neutron numbers, N(i).
In conclusion we would like to stress some advantages of the proposed method. 1. The use of 14-MeV neutrons from the 3H(d, nj4He reaction for homogeneous excitation of lasants by nuclear reaction products allows to pump a medium with any isotope compositions and in any state of aggregation. 2. The available data on cross-sections and energies of the nuclear reactions A(a,b)B for E, = 14 MeV for all isotopes allow to compute the rate of energy deposition of nuclear reaction products. These computations are produced by a Monte Carlo method and have fairly high accuracy f 6%.
E.A. Seregina et al. /Nucl.
Instr. and Meth. in Phys. Res. B 89 (1994) 412-415
3. The use of the statistical single photon counting technique allows to measure the absolute yield of the luminescence photons and in result to obtain a sufficiently reliable information on the conversion efficiency q. 4. The data obtained by means of the offered method are used for the preliminary selection of lasants for NPLs. The proposed technique was successfully employed for an investigation of liquid lasants activated by rare earth ions [12,13]. In summary we want to notice that the suggested method is of interest not only for the diagnostics of lasants for NPLs but also for an investigation of the mechanisms of rare-earth ion excitation by nuclear reaction products.
References HI LASER’-88. Proc. Int. Conf. on LASER-88, New Orleans, USA (1989). El LASER’%. Proc. Int. Conf. on LASER’-90, San Diego, USA (1991). [31 P.P. D’yachenko, Yu.B. Dorofeev, E.D. Poletaev, E.A. Seregina and V.V. Korobkin, Proc. Int. Conf. on LASER’90 (STS Press, McLean, VA, 1991) p. 835.
415
141Yu.K. Voron’ko, B.I. Denker and V.V. Osiko, Dok. Akad. Nauk SSSR 188 (1969) 1258. 151A. NikIas and W. Jelenski, Phys. Stat. Sol. A 77 (1983) 393. 161H.S. Bogdasarov, I.S. Volodina, A.I. Kolomiicev, M.L. Melman and A.C. Smagin, Kvant. Elektronika (Moscow) 9 (1982) 1158. 171Yu.K. Voron’ko, E.L. Nolle, V.V. Osiko and M.N. Timoshechkin, Zh. Eksp. Teor. Fiz. 13 (1971) 125. b31E.A. Seregina, V.V. Kalinin, O.D. Shevchyk and P.P.D’yachenko, Zh. Prikl. Spectrosk. 54 (1991) 788. 191V.M. Bichkov, V.N. Manohin, A.B. Pashchenko and V.I. Plyaskin, Secheniya porogovikh reaktsy, visivaemikh neitronami (Energoisdat, Moscow, 1982). [lOI L.A. Chulkov, Institut Atomnoi Ehnergii, Report IAE2544 (Moscow, 1974). 1111P.A. Androsenko and A.A. Androsenko, Fiziko- ehnergetichesky Institut, report FEI-1300 (Obninsk, 1982). [121 G.T. Petrovsky, E.A. Seregina, P.P.D’yachenko, B.B. Kalinin, O.D. Shevchuk, V.M. Volinkin and C.A. Markocov, Zh. Fiz. Kihm. 55 (1991) 3075. [131 E.A. Seregina, P.P. D’yachenko, V.V. Kalinin, O.D. Shevchuk, O.N. Gilyarov, Yu.1. Krasilov, B.N. Kulikovski and T.L. Novoderezhkina, Neorganicheskie materialy 28 (1992) 162. [141 P.P. D’yachenko, V.V. Kalinin, E.A. Seregina, O.D. Shevchuk, G.V. Tichonov, O.N. Gilyarov, Yu.1. Krasilov, B.N. Kulikovski and T.L. Novoderezhkina, Laser and Particle Beams ll(3) (1993) 493.
Nuclear Instruments and Methods in Physics Research B 89 (1994) 412-415 North-Holland
Beam Interactions with Materials 8 Atoms
Application of accelerator in research of condensed lasants for nuclear pumped lasers E.A. Seregina *, P.P. D’yachenko, V.V. Kalinin Institute of Physics an Power Engineering, 249020 Obninsk, Russian Federation
A technique for measuring a conversion efficiency 7, a lifetime of working level 7 and the position and width of spectral lines of activator ions during excitation of media by nuclear reaction products is presented. The 14-MeV neutrons from the reaction 3H(d, nJ4He have been used for the homogeneous excitation of condensed lasants. The charged particles produced by the interaction of the fast neutrons react with the atomic nuclei of the medium. This technique has been tested on the laser crystal Y,AI,O,, : Nd3+ and has been used for the investigation of laser-active inorganic liquids.
1. Introduction
A problem of today is the search of laser-active media for nuclear pumped lasers (NPLs) [1,2]. To estimate the prospect of some lasant for NPLs it is necessary to know the efficiency of charged particles energy conversion to luminescence energy (conversion efficiency) 7, the lifetime of working level T and the position and width of spectral lines of activator ions during excitation of media by nuclear reaction products [3]. Laser-active inorganic liquids are of great interest as potential lasants for NPLs. However until recently only experimental data for laser crystals and glasses were available. The spectral-luminescence properties of these lasants were measured during excitation by different types of radiation such as X-rays [4-61, electrons [7] and heavy charged particles [8]. It should be mentioned that the high value of the interaction crosssections of all these types of ionizing radiation leads to an effective excitation of solid layers which are only about 0.01-0.1 cm below the surface. In general laseractive liquids are filled in quartz cells. For this reason it is very difficult to excite liquid lasant by short-run ionizing radiation. In order to obtain necessary information about liquid lasant properties the media should be placed into the beam of particles having large penetration capacity, namely into neutron field. In this case the homogeneous volume excitation of lasants is caused by the reaction of charged particles produced by the interaction of neutrons with the nuclei of the medium. * Corresponding author. + This work was supported, in part, by a Soros Humanitarian Foundations Grant awarded by the American Physical Society.
The technique of the investigation of spectralluminescent properties of condensed lasants placed in the beam of fast neutrons is described. This technique has been tested on the laser crystal Y,Al,O,, : Nd3+.
2. Experimental
method
The aim of the method is the measurement of two spontaneous photon emission distributions under the short multi-particle excitation of the active media with nuclear reaction products: the time distribution Qph(t) and the wavelength distribution P(A). The experiments have been carried out at the neutron generator KG-03 of IPPE. Fig. 1 shows the experimental setup. The neutron beam (E, = 14 MeV) was produced in 3H(d, n)4He reactions by a pulsed deuterium beam. The pulse width, frequency and average current on the target are 10 ps, 1 kHz and 2 FA, respectively. The neutrons were recorded by the detector based on a stilben crystal in combination with a photomultiplier FEU-13. The registration threshold was fixed at the value of 6 MeV. The count efficiency of the neutron detector was calculated by a Monte Carlo method using the program “Cristy” [9]. It was 1.9 * 0.2%. The investigated sample has been positioned near the neutron source. 14-MeV neutrons interact with the nuclei of almost all isotopes. The cross-sections of these reactions were measured with high accuracy [lo]. During a very short time charged particles appearing in result of neutron reactions such as A(n, b)B, transfer their energies to the medium and exciting activator ions. The luminescence photons of the sample travel through the quartz waveguides to the entrance slit of the monochromator MDR-23. The photomultiplier FEU-62 working as a photon detector and operating in
0168-583X/94/$07.00 0 1994 - Elsevier Science B.V. All rights reserved SSDI 016%583X(93)E0954-F
E.A. Seregina et al./Nucl. Instr. and Meth. in Phys. Res. B 89 (1994) 412-415
413
the measured photon counting rate n, to the photon numbers radiated by the tungsten lamp is the photon counting efficiency and can be written:
(1)
Fig. 1. Experimental setup. (1) Tritium target; (2) sample; (3) quartz waveguides; (4) neutron detector; (5) amplifier; (6) discriminator; (7) concrete wall; (8) monochromator; (9) photon detector; (10) delay line; (11) two entrance analyzer; (12) CAMAC crate controller; (13) PC.
the single-electron regime, was connected with the slit of the MDR-23. The photocathode of the FEU-62 was cooled by liquid nitrogen vapor to - 50°C. The count rate of phone pulses was lower than 1 s-l. It should be mentioned that the monochromator, the FEU-62 and the other electronic equipment are located in the measuring room shielded by concrete walls from the influence of the radiation. The measuring of the time distributions was carried out by use of a method similar to the well known “time-of-flight method”. The pulse from the target of the neutron generator produces a “start” signal for the registration of the medium excitation moment. Photon and neutron detectors produce “stop” signals. Through discriminators “start” and “stop” signals travel to the two-entrance analyzer of time intervals. The analyzer memory simultaneously stores data of two independent distributions: Qr&) and Q,(r). In addition the lifetime of the 4Fs,2 of Nd3+-ions upon flash lamp pumping was measured by the use of a pulse laser ILGI-503 (A, = 337 nm). The same technique as for measuring Q(t) was used to measure the photon wavelength distribution P(A) and the distribution of the neutron numbers from the generator target, which were directly proportional to the numbers of charged particles exciting the medium. For this purpose the two-entrance analyzer was switched to the multiscaling mode and the monochromator to the wavelength scanning mode. In a special experiment the photon detection efficiency has been measured. In this case a calibrated tungsten lamp served as the source of photons. Using a lens the image of the filament was projected by one-toone magnification into the center of the place, where the sample was located. The photon counting rate nh was measured in the multiscaling mode. The ratio of
where BA,T is the spectral brightness of the lamp’s radiation defined by the Plank formula, K* T the tungsten blackness constant, 6 the spectral width of the outlet slit of the monochromator, S the area of the tungsten filament, K the transmission of the optical system, R the solid angle within which the photons arrive at the collimator of the monochromator. The measurement shows that the value of e* changed from low4 to 10m6 in the wavelength range 340-1150 nm. The principal systematic error of the measuring of lA must be considered as the uncertainty in the calibration of the tungsten lamp. If the uncertainty in the determination of the tungsten filament temperature is It 25”C, the error in E* could be f 25% at A = 600 nm and f 15% at A = 1050 nm.
outlet
3. Results and discussion Time distributions Qr,Jt) were used to determine the lifetimes of excited activator ion levels. Figs. 2a and 2b show the instrumental distributions Q&) of Nd3+ luminescence photons for transitions from levels 2F25,2 (a) and 4F3,2 (b) to the lower levels. The time distribution of the number of neutrons from the KG-O.3 target are shown in this figure too (dashed line). The values of the lifetime calculated from Qr&) were 3.5 f 0.2 us and 210 f 15 ps for levels 2F25,.r and 4F3,2, respectively. The wavelength instrumental distributions of luminescence photons P(A,) are shown in Fig. 3. They were used for determining the absolute yield of photons. The instrumental distribution P(Ai) was treated in the 10
-
D
I---
a
channel
b
number
Fig. 2. Instrumental distributions Q$r) of Nd3+ luminescence photons for transitions of level F2s,, (a) and 4F3,2 (b) to the lower level. Width of the channel is 1 us. IX. MISCELLANEOUS
414
EA. Seregina et al. /Nucl.
Instr. and Meth. in Phys. Res. B 89 (1994) 412-415
following way: one should subtract the background, which was lower then 1 s-l. Then P(hi) was normalized by the average neutron numbers: -
P’(A,)
=fyA&
(2)
where i is the channel number, @ the average number of neutrons from the target, and N(i) the neutron number registered in channel i. Further we have calculated the total energy yield of photons per second in a defined wavelength region using the expression: Ak
Wph = 4PE,h A
c zho
Table 1 Lifetime of ‘F2,,, and 4F,,, levels and conversion efficiency of Nd3+-ions upon excitation by different types of radiation Type of radiation
7 (CL4
n (%)
2=
4F3,2
A(n, b1B
3.5+0.2
f, Q *
3.2+0.2
5/2
(3)
where hi is the wavelength related to channel i, R’(Ai) is the counting rate of photons with wavelength Ai, A = 1.335 nm the monochromator scanning step (width of channel), S the area of the entrance slit, 0 the solid angle, 6 the spectral width of the outlet slit of the MDR-23, L the length of the sample, E,, the mean energy of photons in interval A, - A,. The value of WE, the energy deposited by the nuclear reaction products at the stopping in the active medium, was calculated by a Monte Carlo method using the program “Brand” [ll]. This program code takes into consideration all available information about interaction of neutrons with a substance. The values of cross-sections and energies of nuclear reactions from ref. [lo] were used. These calculations show that the
a
210&15 2.15*0.
41,,2
this work
3.5+0.3 e3.02kO.l y-ray Flash lamp -
R'(h,)A
Sf.k( A,)SL ’
4F3,2
Ref. *4111,2,
215f20 2.0+0.4 180* 10 4.0+ 1.0
200+10 230*30
-
Bl [71 Kl this work
* 7 was measured under excitation by fission fragments of 252cf.
value of w0 (the energy deposition of nuclear reaction products for one neutron from the target) was 9.07 X
lo3 eV cm-3. In our experiment the average neutron flux from the target was 4, = (8.6 f 0.3) x lo8 n s-l. The rate of total energy deposition W, was equal to o,, 4, = 7.8 x 1012 eV cmW3 s-l. The total error in the W, determination was about f6%. It includes the statistic error of the Monte Carlo calculation (0.3%), the error of the neutron reaction cross-section determination (I 2%), the error of the atom concentration measurements (I 2%) and the error of the neutron number measurement (I 5%). Results of r and n measurements for excitation of Y,Al,O,, : Nd3+ by high energy radiation are listed in Table 1. One can see that the lifetimes of the 2F25,2 and 4F3,2 levels obtained in our work are in good agreement with results of other experiments. The conversion efficiency q was only measured in two previous works [7,8]. Here it should be noticed that the value of q measured in the present work is in good agreement with results obtained for excitation of Y Also,, : Nd3+ by o-particles and fission fragments of js2Cf [8].
4. Conclusions
channel
number
Fig. 3. (a) Instrumental distributions of luminescence photons, P&I, for transitions 4F,,, a419,* (1) and 4F3,2 =4I11,2 (2) “0’‘-channel corresponds to 850 nm, width of channel 1.3335 nm; (b) Instrumental distributions of neutron numbers, N(i).
In conclusion we would like to stress some advantages of the proposed method. 1. The use of 14-MeV neutrons from the 3H(d, nj4He reaction for homogeneous excitation of lasants by nuclear reaction products allows to pump a medium with any isotope compositions and in any state of aggregation. 2. The available data on cross-sections and energies of the nuclear reactions A(a,b)B for E, = 14 MeV for all isotopes allow to compute the rate of energy deposition of nuclear reaction products. These computations are produced by a Monte Carlo method and have fairly high accuracy f 6%.
E.A. Seregina et al. /Nucl.
Instr. and Meth. in Phys. Res. B 89 (1994) 412-415
3. The use of the statistical single photon counting technique allows to measure the absolute yield of the luminescence photons and in result to obtain a sufficiently reliable information on the conversion efficiency q. 4. The data obtained by means of the offered method are used for the preliminary selection of lasants for NPLs. The proposed technique was successfully employed for an investigation of liquid lasants activated by rare earth ions [12,13]. In summary we want to notice that the suggested method is of interest not only for the diagnostics of lasants for NPLs but also for an investigation of the mechanisms of rare-earth ion excitation by nuclear reaction products.
References HI LASER’-88. Proc. Int. Conf. on LASER-88, New Orleans, USA (1989). El LASER’%. Proc. Int. Conf. on LASER’-90, San Diego, USA (1991). [31 P.P. D’yachenko, Yu.B. Dorofeev, E.D. Poletaev, E.A. Seregina and V.V. Korobkin, Proc. Int. Conf. on LASER’90 (STS Press, McLean, VA, 1991) p. 835.
415
141Yu.K. Voron’ko, B.I. Denker and V.V. Osiko, Dok. Akad. Nauk SSSR 188 (1969) 1258. 151A. NikIas and W. Jelenski, Phys. Stat. Sol. A 77 (1983) 393. 161H.S. Bogdasarov, I.S. Volodina, A.I. Kolomiicev, M.L. Melman and A.C. Smagin, Kvant. Elektronika (Moscow) 9 (1982) 1158. 171Yu.K. Voron’ko, E.L. Nolle, V.V. Osiko and M.N. Timoshechkin, Zh. Eksp. Teor. Fiz. 13 (1971) 125. b31E.A. Seregina, V.V. Kalinin, O.D. Shevchyk and P.P.D’yachenko, Zh. Prikl. Spectrosk. 54 (1991) 788. 191V.M. Bichkov, V.N. Manohin, A.B. Pashchenko and V.I. Plyaskin, Secheniya porogovikh reaktsy, visivaemikh neitronami (Energoisdat, Moscow, 1982). [lOI L.A. Chulkov, Institut Atomnoi Ehnergii, Report IAE2544 (Moscow, 1974). 1111P.A. Androsenko and A.A. Androsenko, Fiziko- ehnergetichesky Institut, report FEI-1300 (Obninsk, 1982). [121 G.T. Petrovsky, E.A. Seregina, P.P.D’yachenko, B.B. Kalinin, O.D. Shevchuk, V.M. Volinkin and C.A. Markocov, Zh. Fiz. Kihm. 55 (1991) 3075. [131 E.A. Seregina, P.P. D’yachenko, V.V. Kalinin, O.D. Shevchuk, O.N. Gilyarov, Yu.1. Krasilov, B.N. Kulikovski and T.L. Novoderezhkina, Neorganicheskie materialy 28 (1992) 162. [141 P.P. D’yachenko, V.V. Kalinin, E.A. Seregina, O.D. Shevchuk, G.V. Tichonov, O.N. Gilyarov, Yu.1. Krasilov, B.N. Kulikovski and T.L. Novoderezhkina, Laser and Particle Beams ll(3) (1993) 493.