The patent relates to a system and a method to test components, circuits and complex equipments, in order to determine the effect of an external particle flux on the characteristics and operating parameters of such systems or, if applicable, on the software program which drives them. The particle flux can be accompanied by an X ray or gamma radiation flux, at different energies and intensities. Among such systems we enumerate: electric, electronic, optical, mechanical devices or combinations of these, that are present onboard satellites, space ships or planes flying at very high altitude, control systems for nuclear reactors or particle accelerators, equipment used for nuclear material handling and in areas affected by nuclear accidents.

The X radiation represents electromagnetic radiation of wavelength ranging between 10 pm and 10 nm, while gamma radiation wavelength is lower than 10 pm. It is well known that particle fluxes (electron, ion, proton, neutron and other elementary particle fluxes), as well as very low wavelength electromagnetic radiation with dimensions comparable to those of atoms or molecules (such as X and gamma radiation), could inflict severe damage on electronic equipment, leading to malfunction or even total damage (see for example: A. Holmes-Siedle, L. Adams, Handbook of Radiation Effects, Oxford University Press, England, 2002, ISBN 0- 19-850733-X). Therefore development of components and complex electronic, optical and control systems (including software) designed to withstand high intensity radiation levels and operate normally under such conditions, is considered to be of outmost importance. This is why components and systems should be tested in conditions similar to those encountered in critical environments, such as those we describe here. With such aim in view, a mandatory condition is linked to the design and realization of experimental setups able to generate particle and radiation fluxes with characteristics comparable to those encountered in outer space, at very high altitude, inside nuclear reactors or in case of nuclear accidents. In order to test the effect of a high energy particle flux on various equipment, conventional particle accelerators are generally used. Operation of such devices is based on acceleration of charged particles for different electric and magnetic field configurations. Their use has some drawbacks such as:

- generation of particle fluxes requires large dimension facilities -fluxes are generated that consist only of a unique type of particles, which does not allow testing of simultaneous action of several types of particles

- the cross section of the particle flux is very small, which renders impossible testing its effect on the whole tested element or over a significant area of it

- the particle flux is usually monoenergetic, a feature which differs completely compared to the conditions met in outer space or in practice

It is well known that use of high power lasers allows achieving small dimension, compact particle accelerators, with features similar to those of conventional accelerators. Such type of accelerators is based on the generation of particles followed by their acceleration in the plasma which results owing to the interaction between the laser beam and a solid or gaseous target (Refs.: X. Wang, Quasi-monoenergetic laser-plasma acceleration of electrons to GeV, Nature Communications 4, article number:1988, doi :10.1038/ncomms2988, 11 June 2013, and V. Malka, S. Fritzler, E. Lefebvre, M.-M. Aleonard, F. Burgy, J.-P. Chambaret, J.-F. Chemin, K. Krushelnick, G. Malka, S. P. D. Mangles, Z. Najmudin, M. Pittman, J.-P. Rousseau, J.-N. Scheurer, B. Walton, A. E. Dangor, Electron Acceleration by a Wake Field Forced by an Intense Ultrashort Laser Pulse, Science 298, 1596-1600 DOI: 10 A 126/ science.1076782, 2002). In Ref.: X. Wang, Quasi-monoenergetic laser-plasma acceleration of electrons to GeV, Nature Communications 4, article number: 1988, doi :10.1038/ncomms2988, 11 June 2013, a system which generates a 2 GeV energy electron beam is described, based on the interaction between an extremely intense, ultrashort laser pulse of around 1 PW power (150 fs time length, 1.057 μπι wavelength and energy E<150 J), interacting with a gaseous environment consisting of He with 99.99% purity, at a pressure around 1 - 8 Torr, located within a capillary tube of 3 mm diameter and 7 cm length. Such systems intended for particle acceleration based on the interaction between high intensity pulsed laser beams and different types of targets, are called laser plasma accelerators. In case of a conventional accelerator, a distance 10000 times larger is required in order to obtain an electron beam with the same energy spectrum. The laser plasma accelerator is triggered (which means that a bundle of accelerated particles results at its output) by supplying a high intensity ultrashort laser pulse (also called incident laser pulse) at its input, delivered by a high power external laser. The nature, shape and target dimensions, as well as the laser pulse intensity and pulse length determine the type of particles that are generated. By changing these parameters we can control the type and energy of the generated particles. According to S. Abuazoum, S. M. Wiggins, R. C. Issac, G. H. Welsh, G. Vieux, M. Ganciu, and D. A. Jaroszynski, A high voltage pulsed power supply for capillary discharge waveguide applications, Rev. Sci. Instrum. 82, 063505 (2011), an electron accelerator is based on the interaction between a focused laser beam and a filamentary plasma contained within a capillary tube that enables matching the parameters of the accelerated electron beams to the test conditions (pulse length, energy, divergence), by modulating the parameters of the initial capillary current, the pressure value and the type of gas in the capillary tube.

By combining electron, respectively proton acceleration devices, mixtures consisting of ionizing accelerated particles with different structures can be generated, that could also include other types of radiation (X or gamma) or other nuclear particles (neutrons) in a timely controlled manner. In Ref: B. Hidding, T. Konigstein, O. Willi, J. B. Rosenzweig, K. Nakajima, G. Pretzler, Laser-plasma-accelerators-A novel, versatile tool for space radiation studies, Nuclear Instruments and Methods in Physics Research A 636, 31-40 (2011), the authors demonstrate how the energy distribution of particles generated by laser-plasma accelerators exhibits similar features compared to the particles which populate the outer (cosmic) space. Therefore, there exists the possibility to use the flux of particles generated by a laser-plasma accelerator in order to test the effects of particle fluxes (that exhibit features similar to those encountered in the cosmic space) on complex systems (mentioned previously) and on software programs which control them, located on-board satellites and space ships. An already known technical solution consists of a testing system that uses a single laser- plasma accelerator. The high power laser generates very high intensity ultrashort pulses that propagate along a given direction. The pulses are guided towards a parabolic mirror that focuses them on a solid or gaseous target located within the laser-plasma accelerator. Every incident pulse triggers a complex physical process, whose outcome consists of a pulsed accelerated particle flux characterized by a spatial divergence.

In pursuit of the same goal, we recognize the technical solution described in the American patent US2011/0240888 Al from 06.10.2011, which presents a method to test the sensitivity of electronic components and circuits when irradiated. Different types of particles and radiations can be generated, among which electrons, protons, ions, neutrons, photons, and combinations of all these, with a wide range of parameters, of relevance when using electronic components, circuits and systems in the outer space, such as those located on-board satellites, those that operate at high altitudes or in places where radioactive materials are present, such as the case of nuclear power plants. When modifying at least a parameter of the following: the laser pulse energy, the threshold energy of the laser pulse, pulse length, wavelength or the beam distribution and density, a particle flux results that is characterized by an energy distribution of the charged particles close to the exponential one, with an important component consisting of electrons.

In connection with testing of complex components and circuits using small sized, compact particle accelerators, with characteristics comparable to those of conventional accelerators, based on very high power lasers, we refer to known patent applications US2009/0119042A1 from 07.05.2009, ,yMethod of testing an electronic circuit and apparatus thereof and US 2014/0131594A1 from 15.05.2014, "Method for generating electron beams in a hybrid laser- plasma accelerator". The method consists in irradiating the electronic circuit using an accelerated particle beam delivered by a laser-plasma accelerator, and then analysing the response signal at the output of the circuit during application of the particle flux. The method also consists in accumulating samples in order to generate a value, followed by generation of a test result based on such value. According to the patent application, the setup used to test electronic circuits consists of a laser whose output pulse is applied to the laser-plasma accelerator, a control system that directs the accelerated particle beam towards a specific area of the circuit, and a measuring circuit which discriminates a large number of samples out of an output signal while the laser radiation is applied. The setup also comprises a signal processor which accumulates samples and generates a value, and a test result based on such value.

The systems and methods previously described do have certain drawbacks such as:

- The particle beam consists only of a unique type of particles

- The particle beam is delivered only from a single direction

From EP2067049 Bl it is known that a single event upset occurs in a test circuit when applying a particle beam to the integrated circuit device, while driving the scan chain circuit with a clock signal, to generate an output data pattern. The technical issue solved by our patent lies in the fact that two or even more pulsed fluxes of particles and of different types, can be generated simultaneously or with a specific time delay, able to propagate in different directions, characterized by a certain space extent, with characteristics similar to those encountered in the cosmic space. The system described in EP2067049 Bl is complicated and does not test circuits during operating mode. The testing system for components, circuits and complex equipment we devised, solves the above mentioned technical problems. According to the patent application our system is characterized by the fact that, in a first version, it consists of at least two laser-plasma accelerators, placed in different positions with respect to the system which undergoes testing. The system we devised generates at least two pulsed laser accelerated particle fluxes, consisting in identical or different particles, depending on the design of the laser-plasma accelerators. At the input of each one of a minimum number of two laser-particle accelerators, incident laser pulses are applied which result from very high power lasers, so that the surface of the subsystem under test exposed to the particle fluxes is larger compared to the case when a single laser-plasma particle accelerator would be used. One of the laser beams generated by the high power lasers is directed towards a parabolic mirror that focuses the beam to the input of one of the laser-plasma accelerators, while another laser beam, generated by the other high power laser is directed towards another parabolic mirror which in an identical manner focuses the beam at the input of a second laser-plasma accelerator. The setup and method we suggest also consists of the measuring instruments, that are used to achieve calibration of the setup by determining the initial operating parameters for the subsystem to be tested, and to perform measurements of the operating parameters of such subsystem after the particle fluxes were applied.

According to the patent application, the technical solution our system achieves is characterized by the fact that the generated pulsed particle fluxes, consisting of different types of particles, are applied (simultaneously or not) to the same area of the subsystem under test. According to the patent application, the technical solution our system achieves is characterized by the feature that the generated pulsed particle fluxes can be applied to different areas of the subsystem under test.

According to the patent application, the technical solution our system achieves is characterized by the feature that triggering of the output pulses for the two high power lasers is controlled by a complex electronic module which generates drive signals that can lag in time, a unique feature which ensures successive irradiation using the generated particle fluxes of the subsystem to be tested, either of the same area or of different areas of the subsystem. According to the patent application, the technical solution our system achieves is characterized by the feature that the control signals can be simultaneous, which enables simultaneous irradiation of the subsystem to be tested using particle fluxes consisting of identical or different types of particles, either of the same area or of different areas of such subsystem.

According to the patent application, the technical solution our system achieves is characterized by the feature that the number of separate laser-plasma accelerators is selected according to the testing requirements and the dimensions of the subsystems under test, as a function of the power of the lasers and their number.

According to the patent application, the technical solution our system achieves is characterized by the feature that the holder system which holds the subsystem under test can rotate, so that the incident particle flux can be applied under different optical angles and on different areas of the subsystem.

The system we suggest, intended for testing components, circuits and complex equipment, solves the above mentioned technical problem due to the fact that, in case of a second version where we test the effect of radiations, the subsystem under test is made out of at least two separate laser-plasma accelerators. The incident pulse for each of these accelerators is delivered by a single power laser, whose output beam is divided by means of a beam splitter. One of the beams is directed using a system of mirrors towards a parabolic mirror that focuses the beam at the input of one of the laser-plasma accelerators, while the other beam crosses a compensating plate after which it is guided via a system of mirrors towards a parabolic mirror that focuses the beam at the input of the other laser-plasma accelerator. By shifting the aggregate composed of the system of mirrors, one could change the optical path of the laser pulses applied to the input of one of the laser - plasma accelerators, which implicitly generates the accelerated particle fluxes with a certain delay with respect to the other laser-plasma accelerator. The system and method we devised also consists of the measuring instruments (known), that are used to achieve calibration of the setup by determining the initial operating parameters for the subsystem under test and to perform measurements of the operating parameters of such subsystem after the particle fluxes were applied.

According to the patent application, the technical solution our system (method) achieves is characterized by the fact that the generated pulsed particle fluxes, consisting of different types of particles, are applied (simultaneously or not) to the same area of the tested subsystem. According to the patent application, the technical solution our system achieves is characterized by the feature that the generated pulsed particle fluxes can be applied to different areas of the subsystem under test. According to the patent application, the technical solution our system achieves is characterized by the feature that the holder system which supports the subsystem under test can rotate either clockwise or counter-clockwise, therefore the incident particle flux can be applied under different optical angles and to different areas of the subsystem.

According to the patent application, the technical solution our system achieves is characterized by the feature that the holder system which supports the subsystem under test can translate along both the vertical axis and the horizontal plane, hence the incident particle flux can be applied under different optical angles, to different areas of the subsystem under test, that can also be tested under vibration conditions.

Based on the setup we have described above, we can ascertain that the method we have devised to test complex components and circuits under pulsed and synchronized particle fluxes, solves the current technical problem as it is characterized by the fact that, in order to determine the effect of an external flux of particles and radiation of different energies upon the characteristics and operating parameters of the subsystem under test, as well as upon the program that controls such subsystem, consists of:

- Calibration of the system by determining the intensity, the energy, the space distribution and the nature of particles carried by the particle fluxes, for a known intensity of the laser beams, a given spatial configuration of these and specific laser-plasma accelerator characteristics. This is achieved by placing the known measurement instrumentation which helps in determining the mentioned parameters at different space locations that are part of the volume occupied by the subsystem under test;

- Measuring of the operating parameters of the subsystem which undergoes testing in absence of particle fluxes, with an aim to determine its endurance when irradiated;

- Removing the measurement instrumentation and then placing the subsystem under test, for which adequate electromagnetic shielding should be ensured;

- Application of the particle fluxes to the subsystem under test, under conditions of similar characteristics for the laser beams, identical space configuration for these and identical accelerator characteristics;

- Measuring the operating parameters of the subsystem under test during irradiation with particle fluxes, followed by comparison with the values recorded in absence of irradiation. According to the patent application, the technical problem is also solved by the method we suggest as it is characterized by the fact that the calibration procedure is achieved by changing: i) the intensity of the laser beams, ii) their spatial configuration, and by modifying the characteristics of the laser-plasma accelerators, such as the intensity, energy, space distribution, and the nature of particles carried by the particle fluxes lies within the optimum required values.

According to the patent application, the technical problem is also solved by the method we suggest as it is characterized by the feature that the two (at least) accelerated particle fluxes are delivered simultaneously or with a controllable time delay between them onto the component or to the whole subsystem which undergoes testing.

According to the patent application, the technical problem is solved by a method based on the feature that the holder system holding the subsystem under test can rotate either clockwise or counter-clockwise while the tests are performed, therefore the incident particle flux can be delivered under different optical angles and to different areas of the subsystem under test. According to the patent application, the technical problem is solved by a method based on the feature that the holder system holding the subsystem under test can translate along the vertical axis and the horizontal plane, while performing the tests, therefore the incident particle flux can be applied under different optical angles, to different areas of the subsystem under test, that can be also tested for vibration conditions.

According to the patent application, the method and system we suggest intended for testing components, circuits and complex equipment presents the following advantages:

- Simultaneous or operator controlled time delayed generation of multiple particle fluxes with different characteristics

- Generation of pulsed fluxes consisting of different types of particles (electrons and protons, for example), that can be applied simultaneously or with a human operator controlled delay to the component or subsystem of test;

- Delivery of particle fluxes which arrive from different directions;

- Simultaneous or successive irradiation (by means of particle fluxes) of different areas of the subsystem or component under test, thus sensibly increasing the exposed area;

- Simultaneous or successive irradiation of different areas of the subsystem or component under test, that enables simulation of the situation where the particle flux acts upon the most critical elements;

- Pulsed particle fluxes are achieved characterized by a higher degree of uniformity or with controllable space and temporal inhomogeneity; - We can simulate the conditions that emerge in the Solar System in case of solar flares, coronal mass ejections or when a space ship crosses the van Allen radiation belts;

- A large number of damage (malfunctions) can thus be induced in a very short time interval, drastically reduced compared to the lifetime of space equipment. The systems may operate while being tested;

- Specialized software programs can be tested in order to correct the damage induced in the physical structure of the test system, under conditions of instantaneous fluxes for which the probability of simultaneous damage is high;

- The capacity of the whole system to recover and come back to stable operation after inducing multiple damage distributed within a controllable time interval can thus be tested. We further present two examples of implementing the method and system intended for testing components, circuits and complex equipment, according to the patent application, with respect to Fig. 1, 2, 3, 4 and 5 that represent:

- Fig. 1, block diagram of a system intended for particle generation and acceleration, according to the patent application, where the pulsed particle flux is delivered to different areas of the subsystem under test.

- Fig. 2, block diagram of a system intended for particle generation and acceleration, according to the patent application, where the pulsed particle flux is delivered to the same area of the subsystem under test.

- Fig. 3, block diagram of a system intended for particle generation and acceleration, according to the patent application, in a different design version, where the incident pulse for every one of the two laser-plasma accelerators is generated by a single power laser, whose output beam is splitted by means of optical methods

- Fig. 4, block diagram for system calibration procedure, according to the patent application

- Fig. 5, block diagram that points out the multiplication of the incident laser pulse by optical methods

The example schemes illustrate how to achieve and use the S system intended for testing components, circuits and complex equipment in order to estimate the effect of an external particle flux, with different energies, upon the characteristics and operating parameters, as well as upon the program which controls the system operation (if this is the case), according to the patent application, for the situation when the subsystem 1 undergoes testing. According to a first design, the testing system S is made out of two separate laser-plasma accelerators 3 and 4, located at different positions with respect to the subsystem 1 under test which is electromagnetically shielded in an adequate manner, firmly attached to the holder system 2 that can rotate clockwise and counter-clockwise and can translate vertically or horizontally. The holder system 2 allows vibration testing and irradiation of various areas of the subsystem 1 under test. The two laser-plasma accelerators generate the 5 and 6 pulsed accelerated particle fluxes that consist of identical or different particles, depending on the design of the laser-plasma accelerators 3 and 4.

The holder system 2 to which the test subsystem 1 is attached, can rotate or translate such as the particle fluxes 5 and 6 can be applied under different optical angles or to different areas of the subsystem 1 under test. At the input of each of the laser-plasma accelerators 3 and 4 incident laser pulsed beams are applied, which result from two separate high power lasers 7 and 8, therefore the surface of the subsystem 1 exposed to the particle fluxes 5 and 6 is larger compared to the case when a single laser-plasma particle accelerator is used.

The holder system 2 which supports the subsystem 1 can be displaced along the vertical axis, so that the subsystem 1 can be subject to vibration conditions, while the accelerated particle fluxes (5 and 6) can be applied under different angles or to various areas of the subsystem 1 under test.

A laser beam 9, generated by the high power laser 7, is guided by a mirror 11 towards a parabolic mirror 13, which focuses the laser beam 9 to the input of the laser-plasma accelerator 3. Another laser beam 10 generated by the high power laser 8, is guided by a mirror 12 towards a parabolic mirror 14, that focuses the laser beam 10 to the input of the laser-plasma accelerator 4.

Triggering of the output pulses for the two high power lasers 7 and 8 is achieved by means of a module 15, that delivers some control signals denoted by 15a and 15b. The signals 15a and 15b can lag in time one with respect to the other, which allows successive irradiation using particle bunches of the subsystem 1 under test. In such case, the pulsed particle fluxes 5 and 6 are applied to different areas of the test subsystem 1.

According to a different design, the two separate laser-plasma accelerators 3 and 4, placed at different locations with respect to the subsystem 1 under test, generate the 5 and 6 pulsed particle fluxes that can be applied to the same area of the subsystem 1. According to the patent application, the S system also consists of the measurement instruments 27a, 27b, 27c, 27d and 27e, used in order to achieve calibration by determining the characteristics of the particle fluxes 5 and 6, namely the nature, intensity, energy and spatial distribution of these. According to the patent application, the pulsed particle fluxes 5 and 6 could be made out of different particles, thus allowing testing the effect of simultaneous action of different types of particles on the subsystem 1. The particle fluxes could consist out of electrons, ions, protons, neutrons or other elementary particles, as they might be accompanied by gamma or X radiation.

The subsystem 1 under test may include electrical, electronic and optoelectronic devices, or combinations of these. Moreover, the subsystem 1 under test could consist of specialized software used in space industry applications and in any other application which exploits such systems under conditions of high radiation doses and intense accelerated particle fluxes, which can be continuous or intermittent.

In another different design we suggest, the testing system S is made out of two separate laser - plasma accelerators 3 and 4. The incident laser pulse for each of the two laser-plasma accelerators 3 and 4 is generated by a single power laser 16. The output beam 17 generated by the power laser 16 is splitted by means of a beam-splitter 18. One of the beams 19 is directed using a set of mirrors denoted as 20, 21 and 11 to the parabolic mirror 13, that focuses the 19 beam at the input of the laser-plasma accelerator 3. The remaining beam denoted by 22 crosses a compensating plate 23, and is then directed using the mirrors 24, 25, 26 and respectively 12, to the parabolic mirror 14, which focuses the 22 beam at the input of the laser-plasma accelerator 4. By shifting the ensemble composed of the mirrors 24 and 25, the optical path of the incident laser beams applied to the laser-plasma accelerator 19 beam at the input of the laser-plasma accelerator 4 can be modified, which implicitly leads to accelerated particle fluxes 6 that are delayed with respect to those generated by the laser-plasma accelerator 3.

According to the patent application, the method we suggest for testing components, circuits and complex equipment using pulsed and synchronized particle fluxes, based on the test system S, determines the effects of an external radiation and particle flux with different energies, upon the characteristics and operating parameters or, if applicable, to the software which controls them. In order to achieve that, the first step implies calibration of the system S. With such an aim in view, the intensity, energy, space distribution and the nature of particles of which the fluxes 5 and 6 are made of, are to be determined, for a given (known) intensity of the laser beams 9, 10, or respectively 17, for a given space configuration of these, and for given characteristics of the 3 and 4 accelerators, using known instruments denoted by 27a, 27b, 27c, 27d and 27e. The instruments 27a, 27b, 27c, 27d and 27e are used to determine the intensity, energy and the nature of the incident particles, at different positions in space which are part of the volume later occupied by the subsystem 1 under test, and for a given rotation angle of the holder system 2. The calibration procedure is achieved by modifying the intensity of the laser beams 9, 10, and respectively 17, their space configuration, and by changing the characteristics of the accelerators 3 and 4, therefore the intensity, energy, space distribution and the nature of particles carried by the fluxes 5 and 6 should lie within required values. In the second step, the initial operating parameters of the subsystem 1 are measured, as the subsystem 1 is the object of tests concerning particle flux endurance. After calibration and determination of the initial operating parameters, the third step implies removing the measurement instruments 27a, 27b, 27c, 27d and 27e, which are replaced by the test subsystem 1, previously insured against radiation effects through proper electromagnetic shielding.

In the fourth step, the particle fluxes are applied to the subsystem 1 under test. The applied particle fluxes 5 and 6 do possess similar characteristics for the laser beams 9, 10, or respectively 17, under conditions of identical space configuration for each of these, as well as for identical characteristics of the laser accelerators 3 and 4. The fifth step implies measuring, if such is the case, of the initial operating parameters of the subsystem 1 under test in operating mode and then compare the results with the initially measured values from step two. At the end of the tests, in the sixth step, the operating parameters of the subsystem 1 under test are measured once more and they are compared with the initially measured values.

According to the patent application, by applying the method we suggest, the values of the density and energy for a specific type of particles can be determined, for which the subsystem 1 under test retains acceptable operating parameters, either as a whole or only for a set of functions it performs.

In order to apply the method to which our patent refers, the high power lasers 7, 8 or 16 generate laser pulses with an instantaneous power ranging between 10 TW and 10 PW, for a pulse length of 25-50 fs and for repetition rate values ranging between 0.1 Hz and 10 Hz. The parameters of the incident laser pulse are adjusted according to the conditions that are reproduced. For example, in order to simulate the conditions within the van Allen radiation belts we bear in mind that, according to T. Konigstein, O. Karger, G. Pretzler, J. B. Rosenzweig, B. Hidding, Design considerations for the use of laser-plasma accelerators for advanced space radiation studies, J. Plasma Physics, vol. 78, part 4, pp. 383-391 (2012) doi:10.1017/S0022377812000153, the energy distribution for the electron flux within the van Allen radiation belts is approximated using the equation N(E)=Noexp(-E/k _B T), which is similar to the expression that characterizes the electron flux generated by a laser-plasma accelerator. The T _e f = JBT parameter stands for the beam effective temperature. The No and T _e ff parameters depend on the distance with respect to Earth, and the intensity of the solar activity. The parameters are estimated using theoretical models from literature, based on satellite gathered data. According to T. Konigstein, O. Karger, G. Pretzler, J. B. Rosenzweig, B. Hidding, Design considerations for the use of laser-plasma accelerators for advanced space radiation studies, J. Plasma Physics, vol. 78, part 4, pp. 383-391 (2012) doi:10.1017/S0022377812000153, the effective temperature of the electron flux generated by a laser-plasma accelerator depends on the incident pulse intensity /, its wavelength λ, and it is approximated by the expression T _e ff∞ (Ιλ ² ) ^ς νά χ ς = 1/3-1/2. The electron flux peak values during periods of maximum solar activity are three times larger compared to those recorded during minimum solar activity. For example, during the Hipparcos mission, according to M. A. C. Perryman, K. S. O laherty, D. Heger, A. J. C. McDonald, The Hipparcos and Tycho Catalogues, SP-1200, Vol.2 , June 1997, at a distance R = 6.6R , where RE stands for the Earth radius, the recorded electron flux is characterized by the following recorded values: for an electron energy value E _e > 0.5 MeV, the mean electron flux is around 3 x 10 ^u electrons x cm ^"2 x day ^"1 , while for electron energies E _e > 2 MeV, the mean electron flux is around 3 x 10 ⁹ electrons x cm ^"2 x day ^"1 . In case of electron energies E _e > 4 MeV, the mean electron flux is around 7 x 10 electrons x cm ^" x day ^" .

The fluence value for the electrons that reach the surface of a satellite is considered as a reference in order to adapt and use laser-plasma accelerators as electron sources, with an aim to test components and circuits located on-board satellites. In case of a satellite located at a distance of around 3.5RE , an estimated number of around 3 ^χ 10 ¹² electrons x cm ^{"2 χ} day ^"1 reach its surface under conditions of maximum solar activity. A laser whose energy per pulse is around 1 J, under conditions of adequate focusing, can supply (in case of a laser-plasma accelerator) an electron flux at a temperature T _e g= 0.35 MeV and a total charge of around 100 nC/pulse, which corresponds to a number of 6,2 x lO ¹¹ electrons emitted per laser pulse, along the laser pulse direction, for a total divergence angle of around 25 degrees (T. Konigstein, O. Karger, G. Pretzler, J. B. Rosenzweig, B. Hidding, Design considerations for the use of laser- plasma accelerators for advanced space radiation studies, J. Plasma Physics, vol. 78, part 4, pp. 383-391 (2012) doi:10.1017/S0022377812000153). Based on such ground, when using a laser with a pulse length of about 25 - 30 fs, λ= 800 nm, a pulse energy of around 1 J and a frequency of 10 Hz, it follows that for a total surface of 400 cm ² , a time interval of 200 s is required in order to generate a total incident electron flux which corresponds to a day at an altitude of 3,5i? _£ . Thus we prove that use of laser-plasma accelerators assures (guarantees) accumulation of a global irradiation dose within a short time interval, under the major advantage of an electron energy distribution which is similar to the one from cosmic space, namely an exponential one. Another key advantage of the laser-plasma accelerator is the possibility to induce (within a short time interval, e.g. during a laser pulse) a pulsed flux of accelerated electrons, whose instantaneous value exceeds by 10-13 orders of magnitude the value of the maximum electron flux in the van Allen radiation belts, thus allowing to test equipment in case of induced damage for very short time intervals (0.1-10 ns), synchronized with the laser pulse. Such a method also enables inflictment of multiple damage in very short time intervals, a matter of ever increasing interest in order to test the programs which control the operation of circuits and equipment which are acted upon by an external particle flux, that can be accompanied by a flux of X or gamma radiation with different intensity and energy values. By setting the intensity of the laser beams (9, 10 or 17) at adequate levels, particle fluxes can be generated with intensity and energy distribution similar to the one of particle fluxes em encountered in cosmic space. Such fluxes can be measured using the instruments 27a, 27b, 27c, 27d and 27e, of known characteristics. The laser beams 9, 10 or 17, generated by the high power lasers 7, 8 or 16, can be splitted using optical methods by means of optical dividers 28, 29, 30 and 31, thus generating the beams denoted by 32, 33, 34, 35 and 36, therefore multiplying the number of achievable laser-plasma accelerators and consequently the number of available fluxes consisting of accelerated particles.

The pulsed fluxes of particles generated by the S system (which is the subject of the patent application), either simultaneously produced or with variable delays, can exhibit very high values of the cumulated instantaneous intensities, for time intervals in the picosecond range, thus being able to inflict multiple damage upon the systems or components to be tested. Due to the different energetic distribution and different optical path, the multiple induced damage can be inflicted within a time interval in the tenths or hundreds of picosecond range (for relativistic particles, path differences of around 10 cm result in temporal dispersions of their effects of around 300 ps).

Thus a larger number of damage effects can be induced in a shorter time interval that can be smaller than the periods of time characteristic for the operation of the test subsystems 1, that can operate during testing. Thus specialized programs can be tested, aimed at correcting the damage inflicted (induced) in the physical structure of the test subsystem 1, under conditions of instantaneous fluxes for which the probability of simultaneous damage is high. The capacity of the whole system to come back to an acceptable state of operation can thus be verified, after inflicting multiple damage by using a specific time interval distribution.

To summarize, the use of the system and method which is subject of the patent application we submit, is able to ensure based on the above, testing of components, circuits and complex equipment, which may operate or not during the irradiation procedure, as well as testing of dedicated software programs used in space industry and in any other domain which implies exploitation of such systems under conditions of high radiation levels and intense particle fluxes, which may be continuous or intermittent.