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X-ray Capability for Energy Response. Ludlum already has many capabilities in-house:  PMT’s and plastic scintillators  Circuit boards (4-layer SMT)

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Presentation on theme: "X-ray Capability for Energy Response. Ludlum already has many capabilities in-house:  PMT’s and plastic scintillators  Circuit boards (4-layer SMT)"— Presentation transcript:

1 X-ray Capability for Energy Response

2 Ludlum already has many capabilities in-house:  PMT’s and plastic scintillators  Circuit boards (4-layer SMT)  Transformers  Cables and Harnesses  Welding (Alum and Steel)-Robot added 2011  Stamping, Milling, Turning  Die and Mold making  Plastic Injection Molding  Lead Casting  Wire EDM machining  Alpha, Beta, Gamma, and Neutron source calibrations

3 But not much energy response capability. Customers sometimes ask difficult questions about energy response…and not enough monoenergetic radiation sources with long half-lives exist to test well. To test both GM and scintillation detectors, we would need both uR/hr and mR/hr level sources. Sometimes, it’s just not good enough to use supplier or scientific data.

4 As more sales go international…more people are starting to realize that there are energy differences between exposure units and dose equivalent units. “Energy-flat” in terms of exposure isn’t the same as “energy-flat” in terms of dose equivalent. And more people are asking “Why shouldn’t the US join the rest of the world in using the Sievert?”

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6 Once the decision to purchase an x-ray machine was made we needed: 1.A location 2.An appropriate x-ray machine 3.Radiation license and safety 4.Setup and Calibration

7 An unused 2 nd floor site was chosen…with six inch concrete floor and plenty of space- approximately 40 feet wide by 100 feet long.

8 When looking at x-ray systems used by other calibration facilities we found: NIST: Pantak HF320 system LANL: Pantak HF320 system ORNL: Pantak HF320 system PNNL: Pantak HF320 system Ludlum decided to get the same system.

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11 A used (1999) Pantak HF320 system was purchased, which would give crucial energy response data in the 20-300 keV region. An x-ray technician installed and calibrated the system onsite, and provide operational training.

12 Ludlum RSO performed the license modification: radiation source and x-ray devices handled separately. “X-ray in Use” signs and lights installed. Door Interlocks installed downstairs-opening door causes control panel to shut beam off. Radiological survey done inside on the 1 st and 2 nd floors and also outside with beam at full working power and kVp. Procedures written for use, log and safety equipment established.

13 NIST H-series filters-made with 99%+ pure materials

14 Two filter wheels were made, each holding 8 filters. The second wheel hold HVL, used to verify the correct output spectral energy.

15 X-ray Calibration A NIST-traceable PTW ion chamber was used to establish exposure and dose rates at approximately 16 feet. A CdTe isotope identifier (ICS-4000) was used to qualitatively see the spectra.

16 Clearly, we had some serious scattering issues…some additional steel shielding was added

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18 X-Ray Calibration (continued) With the steel shield in place, measurements (again with the NIST-traceable ion chamber) were taken at each of the 8 energies. The HVL filter wheel was added, and the measurements repeated- measurements were within 2% of half-value. Exposure and Dose Equivalent values were then taken at both the 16 and 72 ft distances to give approximately 15 mR/hr and 1 mR/hr exposure distances for GM and scintillation detectors.

19 RESULTS: A version of the 9DP (the Ludlum pressurized ion chamber) has been developed to be energy flat to H*(10) within 20 % from 40 keV to 1.3 MeV, and this result has been verified by an independent lab. More results to follow….

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