Planar Doppler Velocimetry Hardware 

Permanently Sealed Iodine Cell

(Product ID:I2S-5, I2S-10)

sealThe spectrum of molecular Iodine includes discret rotational and vibrational bands with very fine structure in the visible (490-650 nm) spectrum. For this reason, Iodine has been used as frequency references for years. More recently, Iodine has been used as frequency discriminators in Planar Doppler Velocimetry (PDV) and Filtered Rayleigh Scattering (FRS) systems. When used in PDV/FRS systems, the stability of the Iodine cell transmission-vs-frequency profile has been identified as a significant source of error. This instability is caused by variations in the Iodine number density. The number density (pressure) of the Iodine vapor is a strong function of temperature, and therefore, small changes in cell temperature (~ 0.1 °C) can have significant impact on the transmission-vs-frequency profile. An improved design, the starved or super-heated vapor cell, is the basis of the ISSI cell design. To create the permanently sealed starved cell, the cell is evacuated and cold-finger filled with Iodine is brought to the desired vapor pressure (cold-finger operating temperature). The stem between the cold-finger and cell is then permanently sealed with a torch, isolating the Iodine in the cell body and fixing the number density. The cell is then operated 10-20 °C above the cold-finger set temperature and the Iodine in the cell is a super-heated vapor with a set number density. The result is a molecular cell with a very stable absorption spectra.

Specifications for I2S-5

Length 125-mm
Diameter 76-mm
Housing   Anodized Aluminum
Mounting 1/4" -20 Threaded
Maximum Operating Temperature 130 °C
Thermocouple Type T
Set Point 30°C – 50 °C

 

Specifications for I2S-10

Length 250-mm
Diameter 76-mm
Housing   Anodized Aluminum
Mounting 1/4" -20 Threaded
Maximum Operating Temperature 130 °C
Thermocouple Type T
Set Point 30°C – 50 °C

 


Downloads

Datasheet: PDF


 


transmission of cell

Transmision versus frequency for 5-inch iodine cell at a range of vapor pressure set points.

Sealed Cell stability

Long term stability of sealed Iodine Cell


Manifold Iodine Cell

 (Product ID: I2M-5, I2M-10) 

     The spectrum of molecular Iodine includes discret rotational and vibrational bands with very fine structure in the visible (490-650 nm) spectrum. For this reason, Iodine has been used as frequency references for years. More recently, Iodine cells have been used as frequency discriminators in Planar Doppler Velocimetry (PDV) and Filtered Rayleigh Scattering (FRS) systems. When used in PDV/FRS systems the stability of the Iodine cell transmission-vs-frequency profile has been identified as a significant source of error. This instability is caused by variations in the Iodine number density. The number density (pressure) of the Iodine vapor is a strong function of temperature, and therefore, small changes in cell temperature (~ 0.1 °C) can have significant impact on the transmission-vs-frequency profile. An improved design, the starved or super-heated vapor cell, is the basis of the ISSI cell design. To create a sealed starved cell with a flexible set point, a glass cell with an attached cold-finger and vacuum port is constructed. The vacuum port and cold-finger include stopcocks. The cell is evacuated and cold-finger filled with Iodine is brought to the desired vapor pressure (cold-finger operating temperature). The stem between the cold-finger and cell is then sealed by closing the stopcock, isolating the Iodine in the cell body and fixing the number density. The cell is then operated 10-20 °C above the cold-finger set temperature and the Iodine in the cell is a super-heated vapor with a set number density. The result is a molecular cell with a very stable absorption spectra.

Specifications for I2M-5

Length 125-mm
Diameter 76-mm
Housing   Anodized Aluminum
Mounting 1/4" -20 Threaded
Maximum Operating Temperature 130 °C
Thermocouple Type T
Set Point 30°C – 50 °C

 

Specifications for I2M-10

Length 250-mm
Diameter 76-mm
Housing   Anodized Aluminum
Mounting 1/4" -20 Threaded
Maximum Operating Temperature 130 °C
Thermocouple Type T
Set Point 30°C – 50 °C

 


Downloads

Datasheet: PDF


 

manifold iodine cell

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       Manifold Iodine Cell Model (I2M-10)                                                                                                                                                                                                                                        Manifold Iodine Cell Model (I2M-10) Profile

                                                                                                                                                                                                                               

                   

 Call Jim Crafton (xt. 107) with questions or specifications for you application.