User Manual - GAMPT mbH (Gesellschaft für Angewandte
Contents
1. lt 1 mW red or class Illa with power lt 5 mW green Do not look into the beam or aim it at other people or animals gt Beware high powered ultrasound Do not use the probe on people or animals All rights are reserved by the GAMPT mbH No part of this manual may be copied reproduced translated or transmitted in any form without permission of the GAMPT mbH The GAMPT mbH does not assume responsibility for damages as a result of false use as well as repair and changes which are carried out from third not authorized by the GAMPT mbH Technical and software changes reserved Errors and omissions excepted Copyright in 2009 GAMPT mbH Stra e der Freundschaft 25 06179 Zappendorf Phone 49 34609 23683 Fax 49 34609 23684 www gampt de Components Content 1 Introduction 4 2 Components 5 2 1 Ultrasonic generator operating elements 5 2 2 Set up for SC500 test container 6 2 3 Lens on a glass slide 6 2 4 Laser module 6 3 Experimental procedure 7 3 1 Debye Sears effect PHY 11 7 3 2 Projection of standing ultrasonic waves PHY 12 8 3 3 Concentration measurement IND04 9 3 4 General instructions for experiments 10 4 Technical details 11 4 1 Ultrasonic generator 11 4 2 Ultrasonic transducer 11 4 3 Test container 11 4 4 Laser diode 11 4 5 Lens on glass slide 11 Components 1 Introduction In 1932 Debye and Sears demonstrated for the first time how light is refracted when passing t2. Probe adjustment order no GAMPT 20224 x between the N th and N th order of diffraction must be determined From the known wavelength of the laser light 1 the wavelength of the ultrasound wave 4 can then be calcu lated via 1 _2NA s x 1 hs Procedure The distance s between the ultrasound transducer and the dif fraction image is measured by a ruler The maximum order of diffraction N is determined and the distance between the Nth and the Nth order of diffraction x is measured by a calliper or a ruler The measuring is carried out for all frequencies in the range from 1 MHz on in IMHz steps as long as diffraction maxima are visible and separable The measurement is per formed for red as well as green laser light From the measured values the wavelength of sound 4 is determined after 1 and with the known frequency f the sound velocity c is obtained using c f x 2N c cm z m s 19 25 0139 1525 7 1526 2 5 2 8 0 280 756 8 1514 green laser A 532 nm s 325 cm Technical details 32 Projection of standing ultrasonic waves PHY12 Purpose Using divergent laser light the image of a standing ultrasound wave can be demonstrated By means of the originating pro jection image the dependence on the wavelength of light red and green and on the frequency of the ultrasound wave is investigated From the geometry of the projection image the velocity of sound of the test li
3. adjustable between 4 Vpp to approximately 45 Vpp Can be switched off Red control light current restriction adjustable max value 320 mA Display 16 digit LCD for voltage current and power 8 digit LCD for frequency Monitor signal Frequency signal TTL level 5 ss Sinus signal Sinus max 4 Vss Laser output 3 V DC max 300 mW at socket 5 5 mm outer 2 5 mm inner Can be switched off Red control light Dimensions 256 x 86 x 156 mm Main voltage 115 230 V 50 60 Hz Power consumption max 60 VA 5 VA minimum power laser and ultrasound switched off Fuse T 315 mA 230 V T 630 mA 115 V 4 2 Ultrasonic transducer Probe diameter 27 mm Active surface area 2 cm Cable length lm 4 3 Test container Test vessel 100 x 100 x 120 mm Volume ca 900 ml Laser holder 17 mm internal diameter Transducer holder adjustable designed for the supplied transducer 4 4 Laser diode Beam spot lt 6mmat3m Wave length 650 nm Power red lt 1 mW laser safety class II green lt 5 mW laser safety class Ia Supply voltage 3 V DC Current consumption max 35 mA Connecting plug 1 m cable with plug of 5 5 mm outer 2 5 mm inner O Dimensions 80 mm x 17 mm 4 5 Lens on glass slide Lens slide 76 mm x 26 mm glass slide with roughened gripping surface Lens plano convex f 100 mm in air 16 mm
4. frequency probe order no GAMPT 20138 Laser module red order no GAMPT 20210 Sample reservoir with laser support order no GAMPT 20225 Probe adjustment order no GAMPT 20224 Salt stirrer thermometer a TEL I The empirical formula for the sound velocity in sea water af ter Ha en UASA 70 807 12 is 2 t 1448 96 4 591 7 0 05304 T 0 0002374 T 1 34 5 35 0 01025 T 5 35 With T temperature C S concentration of salt fg salt kg sea water Procedure The distance between the ultrasound transducer and the diffraction pattern s is measured by a tape The maximal diffraction order N is determined and the distance between the Nth and the Nth diffraction order x is measured by a caliper The measuring is carried out for a frequency with a ee distance of diffraction maxima and still su ficient number of maxima e g 9 MHz and with the red laser larger diffraction distance From the results of measurements after 1 the wavelength of sound is is determined and with the known frequency f the sound velocity is calculated by caf is A respective amount of rock salt is added in order to enhance the concentration stepwise from 0 to 10 mass per cent After complete solution the measurement is repeated The temperature of the solution is measured in order to take into account the dependence of the sound velocity on temperature The measured and after 1 calculated sound velocities are plotted versus the concentration wave lengt
5. jected 1 Adjustment screw for changing the angle of the transducer 2 Lid 3 Transducer holder 4 Ultrasonic transducer supplied with SC500 5 Securing screw for laser diode 6 Slot for lens holder 7 Laser holder 8 Securing screw for ultrasonic transducer 9 Glass container The following illustration shows how the lens should be properly placed in the test container Class II laser diode for demonstrating the Debye Sears effect and project ing ultrasonic waves for use with the ultrasonic generator and test con 2 4 Laser module tainer 1 seo 2 3 4 1 2 3 4 Laser beam window Laser module jacket Plug for connecting to the ultrasonic generator Connection lead Technical details 3 Experimental procedure 3 1 Debye Sears effect PHY 11 Purpose The light diffraction at a progressing ultrasound wave can be demonstrated Debye Sears effect For this the dependance of the diffraction maxima on the wavelength of light red and green and on the frequency of the ultrasound will be investigated From the geometry of the diffraction image the sound velocity of a test liquid here distilled water is determined Basics In 1932 Debye and Sears could show for the first time that light crossing a liquid that is excited by a high frequency oscillation undergoes a diffraction The density maxima and minima of a standing or continuously progressing wave act like la
6. E CONTROLLER SC500 14 13 12 11 10 9 8 1 display current transducer 10 socket laser diode 2 display power transducer 11 socket sine output BNC 3 display voltage transducer 12 socket TTL output BNC 4 display frequency 13 socket ultrasonic transducer 5 push button decimal point frequency 14 on off SC500 6 adjustment frequency 15 on off transducer 7 adjustment voltage sine output 16 on off voltage transducer 8 adjustment voltage laser output 17 adjustment current transducer 9 on off laser output Technical details 2 2 Set up for SC500 test container 1 2 y I Ip a 1 vr BE 3 4 5 6 7 8 9 23 Lens on a glass slide A plane convex lens is attached to a rectangular slide This is inserted into the slot in the laser holder of the test container for experiments involving projection 1 2 3 1 Plano convex lens 2 Glass slide 3 Grip Standing ultrasonic waves are generated in a special con tainer It allows the angle of incidence of the waves to be set precisely to the perpendicular by means of a special holder for the ultrasonic transducer The test container con sists of a glass vessel with a lid and a holder for the trans ducer three adjustment screws to set the alignment for the standing wave and a laser holder perpendicular to the axis of the waves which also has a holder for a lens so that the ultrasonic waves and the Debye Sears effect can be pro
7. EDUCATION SOUND WAVE CONTROLLER SC 500 Ultrasonic generator with accessories for the Debye Sears experiment and for demonstrating standing ultrasonic waves User Manual Gesellschaft f r Angewandte Medizinische Physik und Technik mbH GAMPT mbH Stra e der Freundschaft 25 Fon 49 0 34609 23683 06179 Zappendorf Fax 49 0 34609 23684 Germany gaM email info gampt de www gampt de AMPT Safety instructions Before switching on the ultrasonic generator and accessories carefully read the following instructions for the sake of your safety and for the safety of the equipment gt The slits in the device are for ventilation and must be kept clear to avoid overheating the equipment It is recommended that the device is placed on its own stand also included gt Before switching on the device make sure that it is adjusted to the main voltage you intend to use Make sure that you keep within the operating specifications gt Never try to push objects through the slits in the device since this could cause short circuits or electric shocks gt Only use GAMPT ultrasonic transducers with the PROBE connection Be careful voltages may be as high as 70 V gt Do not use the ultrasonic transducer for a lengthy period without contact to fluids Otherwise the trans ducer may overheat and be destroyed gt Do not turn on the SC500 laser diode if there are people standing in the beam This is a class II laser with power
8. h red laser A 652 nm Ne2 40 60 con cast ration kai The sound velocity increases cle with the lncreading conceniration of the salt solution and shows in the measuring range 9 10 g g an almost linear the theoretical values values red curve agree in the range of small concentrations lt 3 with Technical details 3 4 General instructions for experiments Pay attention to the following instructions for the experiment to work Use water that contains as little air as possible since air bubbles disturb both the ultrasonic field and the refraction of the laser beam Any air bubbles around the probe should be removed Allow for the maximum distance between the test container and the projection screen When no measurements are being made the ultrasound should be switched off so that the test fluid does not heat up For precise measurements also measure the temperature and include this in the comparison When using high voltage at any frequency and when the transducer is properly aligned at least 3 orders of diffrac tion should be visible The projection experiment is much more sensitive to the angle of the transducer than the refraction experiment Therefore the conditions for generating standing waves must be stable and very precise 10 Technical details 4 Technical details 4 1 Ultrasonic generator Frequency adjustable 0 1 Hz 20 MHz step size 1 Hz Output signal Sine wave continuously
9. hrough a fluid excited to high frequency oscillation The maxima and minima in density act here like the grid elements of an optical diffraction grating The grating constant corresponds to the ultrasonic wavelength and is thus dependent on the frequency of the ultrasound and the speed of sound in the medium through which the sound is travelling The CW continuous wave generator with its accompanying broad band ultrasonic transducer along with an adjustable test vessel and its inte grated laser holder mean that it is possible for the first time to demonstrate this phenomenon to schoolchildren and college students alike using simple and compact equipment The equipment can demonstrate both frequency depend ence with four different frequencies and the ultrasonic wavelength in various fluids allowing the speed of sound in the medium to be calculated It is also possible to project standing ultrasonic waves by inserting an optical lens between the laser source and the ultrasonic waves The waves are then projected by the diverging laser beam 1 SC 500 Ultrasonic generator with laser diode output 2 Laser diode 3 Test container 4 Ultrasonic transducer Components 2 Components 2 1 Ultrasonic generator operating elements The ultrasonic generator generates continuous high power ultrasonic waves CW continuous wave Furthermore it can generate a sinus or TTL signal with adjustable frequencies An additionally adjustab
10. le voltage output can be used for the laser diode of the company GAMPT The transducer will be connected to the SC500 via socket 13 The ultrasonic power can be changed with the trans ducer voltage 16 between 4 and 45 V The maximum reachable current depends from selected frequency and current restriction The maximum current can be adjusted with the potentiometer 17 max value 320 mA In the left LCD display the values for current 1 voltage 3 and electrical power 2 are shown The transducer outlet can be separately switched off 15 the status is shown with a led The frequency will be adjusted with an incremental switcher 6 The push buttons 5 serves to move the changeable decimal place position to right or left The frequency is shown in the right display 4 At the BNC outlets the frequency is given as rectangular TTL signal 12 or as sine signal 11 The amplitude of the sine signal can be changed with controller 7 The laser diode will be connected via socket 10 The laser voltage can be modified with controller 8 The laser outlet can also be separately switched off 9 With the switch Pulse Cont 18 the SC500 can be used as pulse generator In pulse mode no continuous signal cw but short pulses are created The chosen transmitter frequency 4 represents now the repetition frequency It has to be ad justed to the time of flight and must not be selected to high lt 10 kHz 1 2 3 4 na a a SOUND WAV
11. quid here distilled water is determined Basics At exact alignment of the ultrasound probe to the bottom of the vessel a standing wave arises This can be displayed in transmission with divergent light because the sound pressure generates periodic changes of the refraction index On the screen the density distribution of the standing wave will be shown as modulation of brightness The distance of bright ness maxima follows from a AL ER ini 2 s f 2 2 8 8 For the exact determination ofthe wavelength from the image and the geometry the refraction corrections through the glass walls and the measuring liquid have to be considered beside the focal distance f of the lens in air concerning the geom etry see the following scheme Furthermore one has to con sider that by using monochromatic light the focal distance of the lens f as well as the refraction index are functions of the wavelength of light For the exact determination of the wavelength the method of light diffraction is recommended as described in the experiment of Debye Sears effect Results a 4 05cm a 5 65cm s 280 cm g 4 9mm g 3 9 mm f 10 cm with 652 nm red laser sound velocity of water 1482 m s at 20 C Red laser 1 652 nm Green laser I 532 nm As expected from equation 1 the distance of brightness maxima decreases with increasing ultrasound frequency The determined sound velocity value is always too large and is larger for green light too Thi
12. rojection image can be observed The measurement is carried out for red as well as for green laser light From the results of measurement the wavelength of sound 4 is determined after 1 and using the known fre quency f the velocity of sound c is determined after 2 The values are compared for the different laser wavelengths and deviations to values from the literature discussed Technical details Concentration measurement IND04 Purpose The dependence of sound velocity of a salt solution on the concentration is determined by means of the Debye Sears effect and is compared with udn von suntan for he sound velocity in sea water after enzie Basics With increasing concentration in electrolytes a decrease of compressibility arrives This leads to a concentration depen dent increase of the sound velocity From the diffraction patterns of the Debye Sears experiment PHY1 1 the wavelength of the sound wave can be determined and with that the sound velocity of the liquid can be calcu lated The distance between the ultrasound source and the diffraction patterns has to be measured the number of dif fraction maxima N and the distance between the Nth and the Nth diffraction order x must be determined From the known wavelength of the laser light AL then the wavelength of the ultrasound wave AS can be calculated Results distance 3220 mm Setup Ultrasound wave generator SC500 order no GAMPT 20100 Multi
13. s error results from the change of the focal length of the lens due to transmis sion through the glass plates and the measuring liquid The difference between green and red light is explained by the wavelength dependence of the refraction indices Hehe EHH a 3 40 so ise a 7 90 sio is30 4 4 aar ne a 7 69 301 1564 Setup Ultrasound wave generatorSC500 order no GAMPT 20100 Multi frequency probe order no GAMPT 20138 Laser module red order no GAMPT 20210 Laser module green order no GAMPT 20211 Sample reservoir with laser support order no GAMPT 20225 Probe adjustment order no GAMPT 20224 Lens holder order no GAMPT 20230 The distance a between the sound field and the glass wall on the side of the lens can be taken approximately as half the in ner dimension of the vessel minus half of the transducer diameter a follows then from the inner dimension minus a N is the number of brightness maxima and x the belonging distance The sound velocity of the medium c follows from the frequency f after 2 as c A f Procedure The lense support is inserted into the laser support and by that into the optical path The distance between the edge of the vessel and the diffraction image s is measured by a ruler The number of brightness maxima N is determined and the distance x is measured by a calliper or a ruler The measure ment is done for all frequencies in the range from I MHz on in steps of 1 MHz as long as a p
14. ttice elements of an optical diffraction lattice The lat tice constant corresponds to the wavelength of the ultrasound and therefore depends on their frequency and the sound ve locity of the medium From the diffraction images of the De bye Sears experiment the wavelength of the sound wave can be determined and with that the sound velocity in the liquid can be calculated Therefore the distance s between the ultra sound source and the diffraction image must be measured the number N of diffraction maxima and the distance Results As expected from equation 1 with increasing ultrasound frequency an increase of the distance of diffraction orders can be seen When comparing the distances of diffraction orders for the same ultrasound frequency but different laser lights red light gives larger distances The number of diffraction order is determined mainly by the transmission characteristics of the probe and the frequency attenuation The main error results from measuring the distances of the diffraction orders x This can be reduced applying a larger distance s or a suitable optical projection The mean sound velocity of 1479 m s lies near the theoretical value of 1482 m s at 20 C Distance mm Setup Ultrasound wave generatorSC500 order no GAMPT 20100 Multi frequency probe order no GAMPT 20138 Laser module red order no GAMPT 20210 Laser module green order no GAMPT 20211 Sample reservoir with laser support order no GAMPT 20225
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