33B-1-2.pdf

T.O. 33B-1-2

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c. Evaluate the CR image of the erased IP by measuring the pixel value and/or intensity over the entire image using the imaging software tools. See paragraph 2 through paragraph 8 for system specific software procedures.

d. Acceptance Criteria/Corrective Action. If the maximum pixel value is greater than the value specified in the system specific acceptance criteria in paragraphs 2 through paragraph 8, the CR eraser shall be evaluated and corrective action taken per Table 2 before further use.

e. Documentation. Document pass/fail of the test and any corrective actions taken IAW the process control documentation requirements listed in T.O. 33B-1-1.

4.9 Equivalent Penetrameter Sensitivity (EPS). For Crack Detection and Welder Certification systems only - NOT

FOR NAVY USE

NOTE

EPS is analogous to signal-to-noise ratio (SNR) but is independent of system software. The EPS test provides a measure of image quality that has been correlated to detection performance for critical USAF applications. %EPS is defined by an equation in ASTM E1025, which shows the %EPS value decreases as image quality improves (for example: an EPS of 2.0% is equivalent to 2-2T image quality level; an EPS of 1.0% is equivalent to 1-2T image quality level).

a. The EPS Standard (Figure 11, detail (a)) shall be imaged at a distance of 48 inches from the surface of the EPS standard to the X-ray tube. The IP shall be placed immediately beneath the specimen, within the appropriate flexible or hard cassette. A minimum of 1/8-inch thick back screen of lead is required for all exposures.

NOTE

The portion of the IP that is not covered by the EPS standard shall be shielded with lead or another material that is more radiographically dense than the EPS standard to prevent formation of a residual image in the IP after multiple exposures. If available, an 8 x 10 imaging plate may be used for this test, provided it is the same type of IP specified for use with the qualified CR system.

b. Technique parameters for kV, mA, and time shall be determined from Table 6. kV may be adjusted ±10kV, but no other technique parameters shall be changed.

c. Confirm that the pixel value (intensity) measured near the center of the 8 mil EPS plaque is within the allowable pixel value range listed in Table 6.

d. Determine the EPS performance by identifying the hole array where a minimum of 20 holes (out of 30 holes in each hole array) are clearly visible (Figure 11, detail (b)).

NOTE

Similar to conventional penetrameter evaluations, holes which are counted should appear round, and clearly distinguishable from the background image noise.

(1) Visually optimize the EPS image using level (brightness), window (contrast), and magnification only.

(2) Set the level of the image to the approximate pixel value (brightness) measured near the center of the 8 mil EPS plaque.

(3) Reduce the window (contrast) so that the holes can be best visualized.

(4) Magnification can be varied to determine the approximate hole array, but for final evaluation of the EPS data, magnification shall be set at absolute magnification of 1 (i.e. 1:1 image pixel to display pixel ratio).

T.O. 33B-1-2

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Table 6. Technique and PV Range for EPS Test

EPS PARAMETERS FOR CRACK DETECTION

allowable pixelSDD

Time (in-min max CR Scanner IP kV mA (sec) ches)

GE CR Tower GE IPS 65 5 70 48 12000 62000 GE CR50P (50 mi- GE IPS or 65 5 70 48 8000 46000 cron) Carestream/Kodak HR VMI 5100 MS GE IPS or 65 5 70 48 15000 62000

Carestream/Kodak HR Carestream/Kodak GE IPS or 65 5 70 48 2500 3900 HPX-1 Carestream/Kodak HR Durr HD-CR35 Carestream/Kodak HR 65 5 70 48 10000 62000 Durr HD-CR35 GE IPS 65 5 70 48 15000 62000 Fuji Dynamix HR2 Fuji IPS 65 5 100 48 7600 15560 GE CR Flex GE IPS 65 5 70 48 10000 62000

EPS PARAMETERS FOR WELD CERTIFICATIONS

allowable pixel

Time SDD CR Scanner IP kV mA (sec) (inches) min max GE CR Tower GE IPU or Carestream XL 70 5 180 48 12000 62000

Blue GE CR Flex GE IPU 75 5 180 48 10000 62000 Carestream HPX-1 Carestream XL Blue 70 5 180 48 2500 3900 Durr HD CR-35 Carestream XL Blue 75 5 180 48 10000 62000 VMI 5100MS Carestream XL Blue 65 5 180 48 13000 62000 Fuji Dynamix HR2 Fuji UR-1 (25 micron) 65 5 180 48 3000 15560