FR2798764A1 - DEVICE AND METHOD FOR AUDIO RECOVERY OF PARTICLE PROPERTIES FROM COSMIC RADIATION - Google Patents

Abstract

The invention concerns a device and a method for sound reproduction (1) of properties of particles, preferably elementary ionising particles, derived from cosmic radiation. The device comprises a system for spatial detection (11, 12) of particles in several detection points and a sound transmission set (36, 37) coupled with the detection system, capable of transmitting in a plurality of transmission points sounds corresponding in space and time to the properties of the detected particles. The sound transmission set advantageously transmits sounds which differ according to the properties of the detected particles, advantageously in real time relative to the detection of the particles.

Description

The present invention relates to a device and method for sound restitution of properties of particles from cosmic radiation, preferably elementary ionizing particles.

"ionizing elementary particles" are understood to mean not only charged leptons and charged hadrons, but also atomic nuclei.

interstellar space is continuously traveled high energy particle stream: cosmic radiation. These particles are the trace of violent phenomena that liberated and accelerated them somewhere in the universe. Most of them are charged particles, mainly protons, produced in our galaxy, where they are then confined for several million years by the galactic magnetic field to form an approximately continuous and isotropic background of radiation. Their energy spectrum covers a range of about ten orders of magnitude, with a maximum around <B> of GeV followed by a rapid decay at higher energy.

In the vicinity of the earth, cosmic rays interact in the upper atmosphere by creating sheaves of secondary particles, some of which can reach sea level. The most frequent case (primary energy of a dozen GeV) is the production of a penetrating particle, the muon, which propagates to the ground: at sea level, the flow of these muons of cosmic origin is of the order of several tens of Hz per ml. In the rarer cases corresponding to a primary energy greater than a hundred GeV, a sheaf of several muons can be detected on the ground, the number and density of muons providing information on the energy of the primary particle. Sprays of energy greater than a thousand Gev also have an electromagnetic component (mixture of electrons, positrons and photons) large enough to be detected by its wake Cerenkov light radiation. In extreme cases (beyond a hundred thousand GeV), this electromagnetic component can even reach the ground directly.

The human body is by nature insensitive to the ionizing particles produced in the cosmic sheaves. Although there are instruments capable of measuring the properties of such particles, these properties are restored centrally, for example on a computer screen.

The invention aims at a surprising restitution of properties of such ionizing particles, or more generally particles derived from cosmic radiation. This device of the invention has the advantage of being attractive and significant for a wide audience, while being easy to implement and economical.

The device of the invention can thus directly perceive the flow, the trajectory, the direction, the nature, the energy and / or the density of the particles and / or cosmic sheaves, and / or the size of the cosmic sheaves.

Unexpectedly, the invention relates to such a device allowing the unfolding of a real show with unpredictable progress.

The invention also relates to a corresponding sound reproduction method.

The invention thus relates to a device for sound restitution of properties of particles derived from cosmic radiation, preferably elementary ionizing particles, comprising: a system for spatially detecting particles in a plurality of detection points, and a set of sound emission coupled to the detection system, capable of emitting, at a plurality of emission points, sounds corresponding spatially and temporally to the properties of the detected particles.

The detected particles are preferably elementary ionizing particles, but in an alternative embodiment, they are elementary non-ionizing particles.

By "point" is meant areas of the space where the spatial detection system is intended to perform detections discriminated against each other. Similarly, the "emission points" are zones in which the sound emission set is intended to emit discriminated sounds relative to one another. The "spatio-temporal" correspondence between particle detections and sound emissions is in one advantageous embodiment a spatio-temporal identity. In this case, the sound emission assembly emits the sound approximately at the location where the spatial detection system detects the particles and at the moment these particles are detected.

It is understood that even in this advantageous embodiment, the sound emission assembly can only reproduce, in the form of sounds, a small part of the detections made, since the stream of detected particles has a much higher frequency. higher than the frequency of sound emission. In addition, each sound effect has a duration generally much longer than the duration of a detection. These measures make it possible to ensure the audibility of the sounds emitted. Thus, for example, the muons of cosmic origin have at sea level a flow typically of the order of 100 Hz / m2 and their detection lasts a few billionths of a second, whereas the sound effects produced advantageously have a frequency of about 0.5 Hz and a duration of 1 s.

Spatio-temporal "matching" of particle detection and sound emission also encompasses other advantageous embodiments, in which the sound emission is shifted in time or space, and slowed or accelerated by ratio with detection frequency retained for the emission of sounds, or restored in a narrowed space or widened with respect to the real space of detection.

Thus, unlike existing measuring instruments, the device of the invention allows spatiotemporal sound reproduction. The distribution of the properties of the detected particles obeys statistic laws whose random fluctuations can constitute an essential source of unforeseen in the course of a representation.

Among the possible applications of the device of the invention, the following applications are particularly interesting: # Permanent instrumentation of a large dedicated space by a complete set of detectors. Such a device makes it possible to maximize the range of phenomena detected. It can serve as a support for musical performances reflecting the sensibilities of composers tempted by the composition of a cosmos music.

 # A traveling installation intended for representations of the same type, but in various places, for example in the open air under the starry sky. In this case, the emphasis is on the robustness and modularity of the elements of the device, to facilitate the adaptation of its configuration to the topology of each location.

 # An installation with a more didactic vocation, for a science museum for example.

 # Small devices intended for the decoration of public places or even for sale to private individuals.

It may also be interesting to couple the sound reproduction device with visual effects or scenography involving actors, dancers or musicians in action on a stage.

The following four categories of size of the sound reproduction device can be distinguished essentially in terms of both particle detection and sound emission: # medium-sized devices, covering a surface area of 10 to 100 mz, particularly suitable for restitution of properties of isolated particles: # devices of large size, covering an area of 100 to 10 n12, particularly suitable for restitution of properties of large showers of particles that can cover 1 to 20 m side or even 100 m side; # small devices covering approximately 1 2; and # miniaturized devices, for example in the form of individual helmets equipped with small detectors and earphones.

detectors then advantageously have the surface density below, which is in relation to one or more detection surfaces of the spatial detection system: # for devices of average size, between 4 detectors per m2 and 1 detector per 4 m2 , and preferably about 1 detector per m2; # for large devices, 1 detector per 10 to 500 m2; # for small devices, 1 to 10 detectors per m2; and # for miniaturized devices, 100 to 1000 detectors per m2. Preferably, the sound emission assembly emits sounds that differ according to the properties of the particles detected.

Thus, it is possible for a listener to distinguish by ear, for example, the energy of the detected particles, their number or their direction. These differences in sound can be expressed in particular by differences in intensity or frequency (more or less acute or severe sounds), or by the combination of several distinct sounds, or differences in timbre.

In addition, the sound emission assembly advantageously produces particular sono effects aiming for example to simulate movements or shocks, which may be manifested by variations in frequency or intensity. Thus, in particular, the passage of a given particle from one detector to another can be expressed in sound form similar to a Doppler effect, thanks to the variations in intensity and frequency of sounds emitted concomitantly at the two detectors. .

Advantageously, the sound emission assembly is designed to emit the sounds in real time with respect to the detection of the particles. De.plus, preferably, the sound emission assembly is provided to produce sound effects spatially restituting displacements of the detected particles.

This embodiment allows a three-dimensional spatial rendering of cosmic radiation. Advantageously, the sound emission assembly makes it possible to produce the sound effects simulating displacements at the very locations where these displacements take place.

It is particularly advantageous for the sound reproduction device to detect particles and to reproduce sounds in a three-dimensional environment, within which a listener can even be placed.

Thus, preferably, the spatial detection system makes it possible to detect the particles in at least two distinct detection surfaces, advantageously consisting of two parallel planes. Such a configuration is particularly useful for identifying the displacements of particles from one of the surfaces to another, which makes it possible to reproduce the trajectories in a sonorous manner.

 Preferentially, the spatial detection system comprises a network of particle detectors.

The detectors are advantageously chosen from plastic or liquid scintillators, gas detectors such as, for example, wire, drift or plasma chambers, Cerenkov light detectors, calorimeters and silicon detectors.

Preferably, the sound reproduction device also comprises a triggering system connected to the detector array and to the sound emission assembly, intended to selectively authorize the emission of sounds as a function of temporal coincidences between the signals coming from the detectors. Such a triggering system has the advantage of eliminating the background noise of the ambient radioactivity. Advantageously, the triggering system is also capable of performing a received signal filtering by eliminating the detected signals having an intensity lower than a minimum threshold of discrimination.

Advantageously, spatial detection system having at least two distinct detection surfaces, the triggering system is provided to allow the emission of sounds only when at least one of the detectors disposed according to a first of these detection surfaces and at least one other detectors arranged along a second of these detection surfaces perform detections in time coincidence.

The filtering is thus based on the passage of particles by the two detection surfaces concerned, which eliminates parasitic effects. Another advantage of this embodiment is that it allows a sound rendering in the space of the displacement of the particles.

Preferably, the sound emission assembly comprises a network of high-parleul coupled to the array of detectors, preferably having a surface density of between 0.2 and 4 times the surface density of the detectors. The "surface density" of the loudspeakers is that present in sound emission surfaces of the sound emission assembly. Thus, advantageously, the density of the speaker array is the same as the detection resolution, which has the effect of ensuring a good stability of the sound in the space.

In an advantageous embodiment, the surface density of the cells is of the order of 1n2, which corresponds to the spatial resolution power of the ear.

Advantageously. each of the loudspeakers is coupled to a single detector, the loudspeakers and the detectors being preferentially located in one and the same location. Spatial coincidence between detectors and loudspeakers is thus complete.

Detectors and loudspeakers, or at least their exact positions, remain preferentially invisible to listeners in order to allow a better perception of the sound effects.

The subject of the invention is also a sound reproduction method of properties of particles derived from cosmic radiation, preferably elementary ionizing particles, in which: # the particles are spatially detected at a plurality of detection points, and # is emitted in a plurality of emission points of sounds corresponding spatially and temporally to the properties of the detected particles.

The invention will be better understood and illustrated by means of particular examples of embodiment and implementation, in no way limiting, with reference to the accompanying drawings in which: Figure 1 is a schematic view of an embodiment of the sound reproduction device according to the invention; Figure 2 is a diagram of the acquisition electronics of the detectors of the device of Figure 1; Figure 3 is a particular embodiment of the diagram of the acquisition electronics of Figure 2; Figure 4 shows a first embodiment of the sound emission chain of the sound reproduction device of Figure 1; and Fig. 5 shows a second embodiment of the sound transmission chain of the device of Fig. 1. The contents of the figures should be considered as an integral part of the description.

A sound reproduction device 1 (FIG. 1) comprises two parallel networks of scintillator slats, respectively referenced 1 and 12. These two arrays are respectively arranged in a plane P 1 and a plane P2 on the ground. Such scintillator slats, for example plastic, are well suited to detecting the muon component of cosmic sheaves, and make it possible to instrument large surfaces at a reasonable cost and with great ease of implementation.

The slats 11 and 12 advantageously have a symmetrical configuration. They are for example distributed in concentric circles.

The slats 11 and 12 have, for example, a surface area of approximately 0.1 m 2, at a rate of approximately 1 slug per ml, for the instrumentation of a surface area of around 20 μm. Such a segmentation of the space is satisfactory with regard to the power of localization of sound sources by the ear. For a larger installation, the slats 11 and are advantageously more spaced and larger individual surfaces. These slats 11 and 12 are for example based on the BC-400 scintillator material manufactured by BICRON and preferentially emitting in blue.

The slats 11 and 12 are respectively associated with loudspeakers 36 and 37, which in the embodiment shown are arranged at the same locations as the slats.

For example, the loudspeakers 36 and 37 consist of loudspeakers of 50 W.

Advantageously, the up and down arrays of the pairs of detectors and loudspeakers are respectively disposed above a false ceiling and under a platform. The height of the false ceiling in relation to the floor of the stage is then preferably twice the average height of the ears of an individual, or 3.2 m. The materials of the stage and the false ceiling are transparent in terms of acoustics but make the detectors 11 and 12 and the loudspeakers 36 and 37 invisible, so as not to divert the auditory attention of the spectators. The acoustic environment of the device 1 comprises absorbing materials which make it possible to eliminate the reverberations harmful to the three-dimensional sound effects. This environment also offers good isolation of outside noise.

Preferably, the detectors 11 and 12 up and down are aligned to the centimeter, which makes possible the detection multi-nluons sheaves.

In principle, in operation, a spectator 5 places between the two networks of slats <B> II </ B> and 12, therefore in the environment speakers 36 and 37. Cosmic rays 15 of ionizing elementary particles are detected by the slats 11 and they pass through, and these slats 1 1 and 12 emit signals that the device transforms into sounds emitted by the speakers 36 and 37 associated with the slats 11 and 12 traverses. Preferably, the device 1 emits sounds if two of the detectors 11 and 12 respectively arranged in planes P 1 and P2 detect almost simultaneously the passage of a particle. It is therefore interesting that the sounds emitted account for the trajectory of this particle between the ceiling and the ground, by the combined sound effects of the speakers 36 and 37 associated with the slats <B> 11 </ B> and 12 traversed by this particle.

The device 1 will now be more fully detailed, with reference to FIGS. 2 to 5. The device 1 essentially comprises a spatial detection system 2 or 102 (FIGS. 2 and 3 and a sound emission assembly 3 or 103 (FIGS. ) connected a connection 4.

The spatial detection system 2 (FIG. 2) comprises, in addition to the slats 1 1 and 12, photomultipliers 21 and 22 located respectively at the ends of the slats 11 and 12, which collect the lights emitted by the slats and convert them into electrical signals. usable. These signals, which generally last a few nanoseconds, are then processed by a fast electronic chain. Thus, the spatial detection system 2 also comprises discrimination units 23 and 24 respectively connected to the photomultipliers 21 and 22, which compare the received electrical signals to a minimum threshold corresponding to the passage of a particle. The discrimination units 23 are connected to the inputs of an "OR" gate 25 and the discrimination units 24 are connected to the inputs of another "OR" gate 26, the two gates 25 and 26 having their outputs connected to the inputs This electronic arrangement makes it possible to time coincide discriminated signals of the photomultipliers 21 up and down, so that the doors 25-27 constitute a triggering system. Thus, a high-low coincidence signifies the passage of a cosmic particle and produces a trigger signal initiating sound generation steps.

Photomultipliers 21 22 are for example those marketed under the name PM XP 3230B manufactured by Photonis, preferentially powered by a high voltage of the order of 1000 to 1500 V.

The optical transmission between the batten of one of the detectors 11 or 12 and the photomultiplier 21 or 22 associated can be made by simple mechanical contact between the slice of the slat and the window of the photomultiplier 21 or 22, this contact being for example maintained by the pressure of a spring. The entire detector 11 or 12 and the photomultiplier 21 or 22 is usefully wedged by cylindrical PVC spacers, inside a PVC tube closed at both ends by suitable plugs. Preferably, the optical sealing of these assemblies is ensured in order to avoid saturating the photomultipliers 21 or 22 with stray light.

The spatial detection system 2 also comprises an encoding entity 29 in MIDI format, connected to the output of the "AND" gate 27 and, by a central communication link 28, to all the signals emitted by the photomultipliers 21 and 22. The encoding entity 29 has the function of identifying slats 11 and 12 touched by the particles and coding the information obtained in MIDI format. It is capable of treating several slats 11 and several slats 12, activated simultaneously, in order to take into account the case of multi-nltions sheaves, and electromagnetic sheaves.

In a particular embodiment of the spatial detection system 2, referenced 102 and shown in FIG. 3, the detectors 11 and 12 are for example 24 in number (12 high and 12 low) and are divided into distinct groups, respectively referenced 41 and 42 for high and low networks.

Each of the groups 41 and 42 comprises four of the neighboring detectors 11 12 and their photomultipliers 21 or 22 associated, and a local electronics module, respectively referenced 45 and 46 for the high and low networks. This module 45 or 46, connected to the detectors 11 or 12 of the group concerned via photoillustrators S 21 or 22 associated, is responsible in particular for supplying high voltage of these detectors.

Each of the local electronics modules 45 or 46 receives a low input voltage, for example 24 V, and converts it into four individually adjustable high voltages up to a value of 2000 V for distribution to the four connected photomultipliers 21 or 22. to module. This increases safety by avoiding transporting high voltages over long distances. This module also collects the signals from the four associated photomultipliers and, after amplification, compares them to a reference threshold (discrimination). It then transforms the significant signals into a standardized pulse whose length and rise time are adjustable, in order to allow good synchronization of the signals of all the detectors 11 and 12 during the search for temporal coincidences. The functions of the trigger assembly (elements 25-27) and the encoding entity 29 are provided by a processing module 90 associated with a first computer 95. This processing module 90 receives the signals from the modules local electronics 45 and 46 via screened cables 76 at points. Preferably, the signals are transmitted in differential ECL mode. This eliminates the possible effects of coherent noise over long distances. The processing module 90 processes signals from the twenty-four detectors 11 and 12, and makes it possible in particular to time coincide, over a duration of a few tens of billionths of a second, two signals of the high and low networks. This coincidence, which signifies the passage of a cosmic particle in any pair of high and low detectors 11, produces a trigger signal which initiates the reading of the data of the twenty-four detectors 11 and 12 by the computer 95.

The computer 95 receives the TTL trigger and data signals via an acquisition card connected to its internal bus. It performs the following functions: waiting for a triggering signal, and reading the signals of the detectors 11 and 12 on reception of a signal; # shape recognition for identifying the type of event detected (isolated muon, electromagnetic shower or multi muon), possibly filtering events, according to their type or configuration, in order to enrich the rendition in rare events that are more interesting; encoding the relevant parameters of the event (up-down pair, etc.) for transmission to the sound transmission string; - viewing the event on the computer screen 95; # Production of histograms to check the operation of detectors 11 and 12 (individual response rates,.) to easily identify possible faults.

The relevant parameters of each event are transmitted in real time to the sound transmission chain, after conversion into MIDI format by a card connected to the internal bus of the computer 95, by means of the connection 4 The sound emission assembly 3, which includes loudspeakers 36 and 37 also includes in a first embodiment (FIG. 4) a processing processor 30 in MIDI format, connected to the encoding entity 29 (or to the computer 95) by the This processor 30 is capable of driving a battery of synthesizers 31 and a switching matrix 33, according to the information it receives from the encoding entity 29. The processor 30 preferably implements an algorithm specialized in handling MIDI messages.

The programmable switching matrix 33 makes it possible to direct the signals generated by the synthesizers 31 towards the loudspeakers 36 and 37 which must be activated, by means of amplifiers respectively referenced 34 and 35. These latter are advantageously of standard I -1IFI and power at least equal to 50 W. The number of synthesizers 31 depends on the complexity of the sound effects envisaged.

In a second embodiment of sound emission assembly, referenced <B> 103 </ B> and shown in FIG. 5, elements identical or similar to those of the first embodiment are designated by the same references. The sound emitting assembly 103) comprises, instead of the processing processor 30, a processor 50 arranged to digitally perform in real time a sound synthesis and a processing of the MIDI signals received from the encoding entity (or the sound processor). computer 95). This processor 50 is connected to digital / analog converters 51, consisting of cards marketed under the name MOTU 2408 which can process eight channels each. These converters 51 also function advantageously in the analog / digital direction, so as to allow possible interaction with the sound synthesis by providing analog information.

The converters 51 are connected to the networks of the speakers 36 37 via a switching matrix 53 connected to the amplifiers 34 and 35.

In an alternative embodiment, the switching matrix 53 is not used. Preferably, it is present only for a sufficiently large number of channels, and for example at least 24 channels.

According to a third embodiment of the sound emission assembly (not shown), it does not include a digital sound synthesis system, rais memories in which are prerecorded sound effects. These effects are then directly produced in relation to the received signals.

With twelve detectors ll and twelve detectors 12 of dimensions 1 cm3 each, distributed uniformly over an area of about twenty mz, it is possible to detect: # isolated cosmic muons, identified by the temporal coincidence of the signal of a high detector and low detector, at a rate of 1 to 2 muons per second; these muons most often have a vertical direction, but a significant fraction of them have a noticeable inclination of up to 45 and beyond; electro-magnetic sheaves from the interaction of a cosmic milon in the immediate vicinity of the installation; these electromagnetic sheaves consist of an avalanche of photons of electron-positron pairs; they are detected by the temporal coincidence of the signals of two contiguous groups of detectors located on the ground and on the ceiling; a few sheaves of nlulti-nluons resulting from the interaction of a primary cosmic ray of very high energy in the upper atmosphere; these nlulti-muons are identified by the simultaneous detection several muons corresponding to pairs of up-down detectors of parallel and non-adjacent directions; for the detector dimensions indicated above, the expected rate is low, of the order of a multi-muon every few hours; a significant increase in this detection rate is achieved by means of much larger detectors.

Preferably, the sound transmission assembly has capabilities. following: restitution of the impact and the direction of the detected particles, by the main activation of the speakers 36 and 37 corresponding to slats 1 1 and 12 affected, restitution of the direction of movement of the particles, by the simulation of a Doppler effect creating an impression of movement between loudspeakers 36 high and 37 low, restitution of the energy of the event, estimated for the sheaves of nlulti-muons by the number and the density of the muons detected, thanks to a modification of the intensity and the timbre of the sounds emitted, restitution of an avalanche effect associated with an electromagnetic sheaf, by the production of a "sound streaming" in the direction of the sheaf, superposition to the sound events in real-time background music, which enhances the auditory concentration of the audience.

Claims (1)

<U> CLAIMS </ U>. Device (1) for sound restitution of properties of particles derived from cosmic radiation, preferably elementary ionizing particles, comprising: a system for the spatial detection (2, 102) of said particles in a plurality of detection points, and # a set of sound emission (3, 103) coupled to the detection system (2, 102), capable of emitting at a plurality of emission points sounds corresponding spatially and temporally to the operations of the detected particles. Device according to claim 1, characterized in that the sound emission assembly (3, 103) emits sounds which differ according to said properties of the detected particles. Device according to one of claims 1 or 2, characterized in that the sound emission assembly (3, 103) is provided for transmitting said sounds in real time with respect to the detection of said particles. 4. Device according to any one of claims 1 to 3, characterized in that the sound emission assembly (3, 103) is provided to produce sound effects spatially restoring displacements of the detected particles. 5. Device according to any one of claims 1 to 4, characterized in that the spatial detection system (2, 102) detects said particles in at least two distinct detection surfaces, preferably consisting of two parallel planes (P1 , P2). . Device according to one of Claims 1 to 5, characterized in that the spatial detection system (2, 102) comprises an array of particle detectors (11, 12). Device according to Claim 6, characterized in that the said detectors <B> (11, </ B> 12) are chosen from liquid or liquid plastic scintillators, gas detectors, light detectors, calorimeters and silicon detectors. . 8. Device according to one of claims 6 or 7, characterized in that it also comprises a triggering system (25-27, connected to the detector array (I1, 12) and to the sound emission assembly (3, 103) for selectively authorizing the transmission of sounds as a function of time coincidences between the signals from the detectors (1, 12) 9. Device according to claims 5 and 8, characterized in that the triggering system (25-27, 90) is provided to authorize the emission of sounds only when at least one of the detectors (I1) disposed on a first of said detection surfaces (P1) and at least one of the other detectors disposed according to a second one of said detection surfaces (P2) perform time-coincidence detections 10. Apparatus according to claim 6 and any one of claims 6 to 9, characterized in that the sound emission assembly (3, 103) comprises a high-p network arleurs (36, 37) coupled to the network of said detectors 1, 12) and preferably having a surface density of between 0.2 and 4 times the surface density of the detectors. 11. Device according to claim 10, characterized in that each of the speakers 37) is coupled to a single one of said detectors (11, 12), said speakers and detectors being preferably located at the same location. 12. A method of sound restitution of properties of particles from cosmic radiation, preferably elementary ionizing particles, wherein: # said particles are spatially detected at a plurality of detection points, and # emitted at a plurality of emission points sounds corresponding spatially and temporally to the properties of the detected particles.