US3004735A - Particle detection apparatus - Google Patents

Description

W. H. KINARDv PARTICLE DETECTION APPARATUS Filed DeC- 21, 1959 EEEEW Ill: vIll:fifilllnllllnlllllllllrlflllrlfllllillflllll INVENTOR WILLIAM H KINARD ATTOEYS United StatesPatent 3,094,115*if H 1 PARTICLE DETECTION APPARATUS William H. Kinard, Newport News, Va., assignor'to the United States of America as represented by the Admmistrator of National Aeronautics and Space Administration l Filed Dec. 21, 1959, Ser. No. 861,152

l14 Claims. (Cl. 244-14) l (Granted under Title 35, UJS. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalities thereon or therefor.

This invention relatesgenerally to particle detectors, and more particularly to detector apparatus for indicating the frequency of incidence and energy of minute space particles.

iIn space craft intended for orbital or interplanetary flight, it is necessary for the skin thereof to be capable of withstanding collisions with minute space particles, such for example as micro-meteorites, or the like, to protect the instruments and/or occupants carried by the space craft. In order to insure the adequacy of the skin, or shell, structure, it is desirable that the design thereof be based upon information indicative of the collision conditions likely to be encountered by the space craft, orvehicle.

Although particle collisionedetectiageevieesehave beeae;ea reactedefeaaeeatral plaaaesectien'ls'eonpesedeefaev other objects are attained bythe provision of an erectable and insulating' materials, a common source of potential energy, a common indicating device, and an electrical impedance individually coupling each of the conductive layers to the energy source and indicator.

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily apparent as the same becomes better understood by reference to the following detailed description when considered'in connection with the accompanying drawing wherein:

FIG. l is a side elevational view of the aerospace particle detector in its fully extended and operational condition;

FIG. 2 is Ian enlarged view, partially in section, of the electrical circuitry utilized in the present invention; and,

FIG. 3 is Ia side elevational view, partially in section, of the aerospace particle detector in its stored for launching condition.

Referring now to the drawing, wherein like reference numerals designate identical or corresponring parts throughout the several views, and more particularly to `FIGS.'1 and 2, the particle vdetector apparatus according to the' instant invention is shown as consisting essentially of ra data recording system 11 shock-mounted in a nose cone 12 and ya target body 13 capable of being towed behind the nose cone. The target body, or sail, 13 is conheretofore devised and utilized, in general, these prior art eral superposed :thin sheets of laminated material, and

detection device provides for the disposition of a microphone and counter within the casing of the space vehicle. The microphone provides a signal to the counter in rcsponseto the acoustic noise generated by each particle collision with the vehicle casing. Although this latter system overcomes the aforementioned shortcoming of the former system, neitherof these prior art arrangements are capable of providing a measurement ofthe energy content of the colliding particle.

An object of this invention is therefore to provide a new and improved apparatus for determining the'incidence and energy Vcontent of minute particles.

Another object of the instant invention is the provisionV of a new and improved electrical system for accur-ately counting the frequency of occurrence of small-sized solid particles.

Still another object of the present invention is the provision of a new and improved electrical system for accurately indicating the magnitude of momentum of smallsized solid particles.

A further object of this invention is to provide a novel towable aerospace target selectively responsive tothe impiugement of minute particles of matter.

Vpact packaged condition and of being erected to a* fully extended condition.

According to the present invention, the foregoing and interconnected peripheral and diagonal tubuluar channels 15 -adhesively secured thereto as at 16. The laminated sheets are formed of -a base layer 17 of tensionally strong and flexible insulating material, such for example as the polyester Mylan to which is secured -a layer 18 of lightweight and bendable electrically conductive material, such for example as aluminum. The aluminum may be secured to the base layer by the use of an adhesive or by a conventional metal depositing process. The tubular channels 15 may be formedrof rubber, parachute cloth, or the like, but Mylar is a preferred material. A pair of valves 19 are provided in a forward tubular channel through which an iniiatng medium, such for example' as compressed air, or a plastic foam, such for example as a polyester, is introduced for distribution to all of the channels 15 thereby imparting a degree of rigidity thereto and full extension of the target sail 13. The inating or stiffening medium may Vbe'applied to the valves 19 through a hose-like tow line Y20 connected to a storage container 21 positioned within the nose cone 12. The tow line is preferably in threaded engagement with the valves 19V and container 21. To minimize the likelihood of bucklingof the target sail, one or more diagonal channels also may be formed thereon. It will be apparent to one skilled in the art that byV reason of the lightweight structural nature of the target body 13, a substantially large sized sail can be deployed for sampling a greater spatial area thereby increasing the statistical accuracy of the data obtained.

As more clearly shown in FIG. 2, the data recording system 11 utilized in the present invention consists of an electrical energy source, such for example as a charged condenser 22, one plate of which is electrically coupled through conductor 23 to an outermost aluminum layer 18 ofthe target sail, and the other plate of whichis eleceV trically coupled throughV conductor 24 to a load impedance, such for example as a resistance 25. Each of the remaining aluminum layers 18 is coupled through an individual conductor 26 of an electrical cable 27 to in-Y miniature sized telemetering transmitter 32 is parallel coupled to the common load resistance 25.

vPrior to assuming the fully extended and operational condition illustrated in PIG; 1, the target sail 13 is carried aloft in a `collapsed. and compactly folded condition within an open ended container 33 formed inthe after portion of the nose cone 12 of a launchingvvehicle, or rocket, 34, as shown in. FIG. 3.2 The nose cone .12 is secured'to the propellant motor'BS byV conventional means, not shown. When the-rocket. 3.4. has reached the desired altitude at which it is desired to deploy the target sail, as

may bev determined. by a conventional4 altimcter, or timing. mechanism 36,:the nose. conev Lzfis. detached from the motor-'35 by conventional means, not shown.` Upon separation ot the noseV cone 12, theA collapsed target sail 13 is ejected from its container 33 by conventional means, such for example as a Ycompressed spring 37. Flow of the inliating medium from storage container 21 will then be initiated through towing conduit v and unfolding o the target sail Vuntil fully extended will result. L

In operation, an impinging space particle 38; will penetrate the target sail 13y toA a depth proportionateVA to the level ot momentum thereof, as shown in- FIG. 2;. The

v penetration'of each layer will he attended by thev release,

in the small. immediate area, of la. high level of energy, which is sumcient to successviely vapon'ze the nearby target materials and thenmionize the resultant vapor. Thus, as the particle penetrates. thev stacked. array of laminated sheets. of the central sailfportion 14,. ionization oi each layer of almninum penetrated will occur, thereby effectively producing a. short circuit path between adja cent penetrated aluminum layers 18. As successive adjacent aluminum sheets become short circuited, successive ones of resistors 28 will be placed in parallel with one another in the discharge path of charged condenser 22.

vThe discharge time constant of the circuit will be'correspondingly reduced with a consequent increase in the potential signal, or drop, across.A load resistor 25. Prior calibration of the potential signal `developed across. the

load resistance in response to the introduction of successive ones of resistors 2.8 will allow for a measurement of the depth of penetration of the colliding particles, from which data the momentum of the particles can be readily determined. The potential signal across the load resistor is recorded by the recorder 31 and/ or suitably transmitted by transmitter 32 to a remote receiving station. Inasmuch as the ionization phenomenon is short lived; i.e., two milli-seconds duration, and with the exceeding rarity lof simultaneous particle impingement, an accurate measurement of each particle collision and the momentum thereof will be obtained.

Whereas the operation of the device according toY the present invention has been described in connection with a missile, or rocket, nose cone, it is not so limited, and may also be used with equal advantage in connection with aerial vehicles, suchy for example as aircraft, or the like.

Obviously many modiiications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as. speciiically described.

What is claimed Ias new and desired to be secured by Letters Patent of the United States is:

l. A collapsible target comprising a planar section formed of alternate layers of flexible and tensionally strong non-conductive material and lightweight and bend- `able metallic material, ya continuous enclosed channel formed of tlexible and tensionally strong non-conductive material connected to the periphery of said planar section, andA means for introducing an inflating medium into said channel to elect erection of the target.

2. A collapsible aerospace target. comprising a planar section formed of superposed. alternate-layers of polyester material and aluminum material, a continuous tubular member formed. of polyester material adhesively attached to said planar section alongthe entire periphery thereof, a valve positioned in said tubular member, andl means coupled to said valve for introducing an inflating medium into said tubularmemher-to.- ecct. erection of the vaerospacetarget..

3. A collapsiblex aerospace target' according to claim- 2 and including at least one tubular member diagonally attached to said planar section and formed; integrally withv said continuous tubular member. 4. A collapsible aerospace target according to claim 3 wherein. said intiating medium isaplastic foam.

5. A particle detection system vcomprising a `target formed of superposed alternate layers of flexible vauditeusionally strong` nonconductive materiali-and` lightweight `and bendable metallic material, a plurality of impedances,

each of which is individually coupled toone of; said ntie.-V tallic layers, an electrical energy source, coupled to. one

metallic layer, and means coupled betweeny said energy sourceA and said pluralityy ofimpedances responsive to potential variations resulting from the momentary ionization of said metallic layers penetrated'by particles: colliding with said target..

6. Arsystem according to claim 5: wherein said means comprises a recording device; Y

7. A system according to claim 5. .wherein said means comprises a transmitter.

8. A system according to claim 5 wherein said. e1ec .trical' energy source comprises a chargedV condenser.

9; An aerospace particle detection; system comprising a propelled vehicle, a target sail disposed in said vehicle inra collapsed condition, said target sail being formed of alternate layers of polyester and aluminum materials, a continuous iiexible tube attached to the periphery of said target sail, a container of an inllating medium disposed in saidfvehicle, a exible conduit coupled tosaid container and toV said tube for towing said target sail behind said vehicle upon ejection therefrom and for transmitting said inilatingmedium to said tube thereby electngV erection of said target sail, circuit means disposed in said vehicle, said circuit means including an electrical energy source coupled tov one of said aluminum layers, a plurality of impcdances, each of which is individually coupled to one -of said aluminum layers, and means coupled between said energy source and all of said plurality of impedances responsive to energy flow variations in said circuit means resulting from the momentary ionization of said aluminum layers penetrated by particles colliding with said target sail.

l0. Au aerospace system according to claim 9y wherein said means comprises a recording device. A

ll. An aerospace system according to claim 9 wherein said means comprises a transmitter.

12. An aerospace system according to claim 9 wherein said means comprises a recording device and a transmitter.

13. An aerospace system according to claim 9 wherein said electrical energy source comprises a charged condenser.

14. A particle detection system comprising a target -formed of superposed alternate layers of nonconductive material and metallic material, a plurality of impedances, each of which is connected to. one of said metallic layers, an electrical energy source connected to one metallic layer, and means coupled to said energy source and to said plurality of impedances for responding to potential variations resulting from the momentary ionization of said metallic Vlayers penetrated by particles colliding with said target.

References Cited in the tile of this patent UNITED STATES PATENTS

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