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01:46 Sep-16-2005
Scott
2% or Really 4% Sensitivity


The codes for radiography typically specify a 2-2T sensitivy level to be achieved.

Would this not really be a 4% level of sensitivity? The penetrameter is 2% of the thickness of the weld and the 2T hole diameter is 2x thickness of the penny. Does this not give 4% sensitivity?

2-2T really means, The 2 is 2% sensitivity (able to see 3 sides of the penny) and be able to see the 2T hole. But if you can see 3 sides but not the hole, is this still not 2% sensitivity.

Its a little confusing. Can someone please explain this.


 
05:14 Sep-18-2005

S.V.Swamy

Engineering, - Material Testing Inspection & Quality Control
Retired from Nuclear Fuel Complex ,
India,
Joined Feb 2001
784
Re: 2% or Really 4% Sensitivity Dear Scott,

The thickness of the penetrameter is so chosen that a difference in density of nearly 2% is seen on the film. The diameter of the hole, which is 2% of the strip is chosen so that a small detail like the hole is seen, thus confirming the technique's Image Quality. The sharpness of an image depends on several factors including the spectral quality of the radiation, the graininess of the film and the Source to the Film Distance. These need to be optimised so that a small detail like the penetrameter hole or a thin wire (for a DIN type penetrameter) is seen. That is the reason the penetrameter or penny is now called IQI Image Quality Indicator.

2-2T thus does not become 4%.

Swamy

----------- Start Original Message -----------
:
: The codes for radiography typically specify a 2-2T sensitivy level to be achieved.
: Would this not really be a 4% level of sensitivity? The penetrameter is 2% of the thickness of the weld and the 2T hole diameter is 2x thickness of the penny. Does this not give 4% sensitivity?
: 2-2T really means, The 2 is 2% sensitivity (able to see 3 sides of the penny) and be able to see the 2T hole. But if you can see 3 sides but not the hole, is this still not 2% sensitivity.
: Its a little confusing. Can someone please explain this.
------------ End Original Message ------------




 
05:27 Sep-18-2005
Scott
Re: 2% or Really 4% Sensitivity Thats doesnt really answer what I was asking. The hole is not 2% of the strip (I assume you mean penny thickness)The diameter is 2x the tickness of the penny for the 2T hole. The 1T hole is 1X the thickness of the shim, which is 2% of th thickness of the weld. So I am still confused as to why a hole who's diameter is 4% of weld thickness is not considered 4% sensitivity.


----------- Start Original Message -----------
: Dear Scott,
: The thickness of the penetrameter is so chosen that a difference in density of nearly 2% is seen on the film. The diameter of the hole, which is 2% of the strip is chosen so that a small detail like the hole is seen, thus confirming the technique's Image Quality. The sharpness of an image depends on several factors including the spectral quality of the radiation, the graininess of the film and the Source to the Film Distance. These need to be optimised so that a small detail like the penetrameter hole or a thin wire (for a DIN type penetrameter) is seen. That is the reason the penetrameter or penny is now called IQI Image Quality Indicator.
: 2-2T thus does not become 4%.
: Swamy
: :
: : The codes for radiography typically specify a 2-2T sensitivy level to be achieved.
: : Would this not really be a 4% level of sensitivity? The penetrameter is 2% of the thickness of the weld and the 2T hole diameter is 2x thickness of the penny. Does this not give 4% sensitivity?
: : 2-2T really means, The 2 is 2% sensitivity (able to see 3 sides of the penny) and be able to see the 2T hole. But if you can see 3 sides but not the hole, is this still not 2% sensitivity.
: : Its a little confusing. Can someone please explain this.
------------ End Original Message ------------




 


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