Detector Based Apparatus for

Ultrasonic Diffraction -

Acousto optic effect

Model: HO-ED-A-01

The Ultrasonic diffraction apparatus is used to study diffraction of light by ultrasonic waves. Ultrasonic sound refers to sound with a frequency greater than the human audible range (20Hz to 20 KHz). When an ultrasonic wave propagates through a medium, the molecules in that medium vibrate over very short distance in a direction parallel to the longitudinal wave. The apparatus consists of a graduated long rail and rail carriages appropriately fitted with laser head, an RF oscillator and a detector with translation stage. The ultrasonic diffraction setup uses laser as light source. As the laser beam is intense and monochromatic, we get clear higher order diffraction pattern.

The ultrasonic waves generated by the transducer travels down the medium (liquid) and gets reflected at the bottom (flat glass plate) of the cell. The incident and reflected waves interfere and a stationary / standing wave pattern is formed. The laser head is mounted using a kinematic holder. This helps to direct the laser beam through the liquid and then to the detector conveniently. The diffraction pattern is scanned using a translation stage with freedom in X axis. The velocity of ultrasonic waves in liquids can be calculated from this experiment. This instrument is designed to give accurate and best results.

Experiment Examples

To find the velocity of ultrasonic wave in liquids

The velocity of ultrasonic wave in a liquid,

V   =   ʋ ʌ

Where υ is the frequency of the crystal oscillator and Λ is the wavelength of ultrasonic wave.

We have,

Λ   =   n λ / Sin θ

Where n is the order of diffraction, λ is the wavelength of the laser used and θ is the angle of diffraction.

θ   =   tan-1 ( D / L )

D is the order length and L is the distance measured from the crystal oscillator to the detector.

To find the bulk modulus of the given liquid

The bulk modulus of the liquid,

β   =   ρV2

Where ρ is the density of the liquid and V is the velocity of the ultrasonic wave.

To find the compressibility of the liquid

The compressibility of a liquid is the reciprocal of bulk modulus,

K   =   1 / ρV2

Where ρ is the density of the liquid and is V the velocity of the ultrasonic wave.

Specification of Piezo Electric Crystals

Dimension   :   20 mm diameter x 0.7 mm thickness

Resonant frequency fr   :   3 MHz ± 50 KHz

Resonant impedance Zm   :   ≤ 6 Ω.

Static capacitance Cs   :   570 0pF ± 15% @ 1 kHz

Dimension   :   20 mm diameter x 0.4 mm thickness

Resonant frequency fr   :   5 MHz ± 100 KHz

Resonant impedance Zm   :   ≤ 0.48 Ω.

Static capacitance Cs   :   3800 pF ± 20% @ 60 Hz/1 V

Fig: Optical system for observation of diffraction by ultrasonic waves

Fig: Graph shows distance Vs. detector current

Features

Precision design

Diode laser is used as light source

5 MHz,3 MHz crystals

Corrosion free

High quality photo detector

Related Topics

Interference

Standing waves

Huygens' Principle

Bulk modulus

Compressibility

Scope of Supply

Optical Rail

Model No: ED-A-01-OR
Length
:
1500mm
Material
:
Black anodized Aluminum alloy
Quantity
:
1 no.

Kinematic Laser Mount

Model No: ED-A-01-KLM
Material
:
Black anodized Aluminum alloy
:
:
+/-4 degrees
Quantity
:
1 no.

Glass tank Mount with Crystal Holder

Model No: ED-A-01-GMCH
Material
:
Black anodized Aluminum alloy
:
Quantity
:
1 no.

Detector Mount with X- Translation

Model No: ED-A-01-DMXT
Material
:
Black anodized Aluminum alloy
Travel
:
Micrometer controlled
Resolution
:
0.01 mm
Diameter
:
30 mm
Quantity
:
1 no.

Glass Tank

Model No: ED-A-01-GT
Material
:
Float
Dimension
:
50 x 35 x 35 mm
Quantity
:
2 nos.

Piezo Electric Crystals

Model No: ED-A-01-PEC
Frequency
:
3, 5 MHz
Quantity
:
1no. each

RF Oscillator

Model No: ED-A-01-RFO
Frequency Range
:
2 - 6 MHz
Quantity
:
1no.

Diode Laser with Power supply (Red)

Model No: ED-A-01-DLPR
Wave length
:
650 nm
Optical power
:
3 mW
Quantity
:
1no.

Detector Output Measurement Unit

Model No: ED-A-01-DOMU
Sensor Type
:
Photo Transistor
Display
:
7 segment, 3 ½ digit
Range
:
0 - 199 milli / micro amperes
Quantity
:
1no.

Accessories

Test Sample
Connecting Cables
User Manual

Glass Tank / Cuvette

Model No. ED-A-01-GT
\$ 46.00

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