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Well ionization chamber calibration with electronic brachytherapy sources
Well ionization chamber calibration with electronic brachytherapy sources
X-ray radiation calibration services are temporarily suspended. We anticipate resumption of services no later than May 15, 2025.
Primary NIST Technical Contact:
Secondary NIST Technical Contact:
(Each additional source)
The calibration of well-type ionization chambers, instruments that measure x-rays from electronic brachytherapy sources, is performed in terms of the physical quantity air-kerma in units of Gy. Calibrations are performed by comparing the well-type ionization chamber response to air kerma realized by a NIST primary x-ray standard. The measurement process results in a NIST calibration coefficient for the well chamber for each source in units of the NIST air-kerma rate (Gy/s) at 50 cm per ampere, Gy/(A s) normalized to 295.15 K (22 oC) and 101.325 kPa (1 Atm). Only well-ionization chambers known to be stable and reproducible are accepted for calibration in this program. Facilities submitting well-ionization chambers for calibration are strongly urged to perform stability checks involving redundant measurements in highly reproducible radiation fields before sending their instruments to NIST, and to repeat those checks after NIST calibration, and again at suitable intervals. The appropriate chamber insert must be provided by the customer. Calibrations of x-ray measuring instruments have a relative expanded uncertainty of 1 %.
Key comparison BIPM.RI(I)-K3 of the air-kerma standards of the NIST, USA and the BIPM in medium-energy x- rays, C M. O'Brien, D T. Burns, Ronaldo Minniti, Metrology 54, (2017).
Methods for characterizing a radiation detector for specifying radiation fields during testing against standards for homeland security applications, Anne L. Sallaska, Leticia S. Pibida, Ronaldo Minniti, C M. O'Brien, NIST TN 1916 (2016).
SIM.RI(I)-K3 Comparison of Calibration Coefficients at Radiotherapy Level for Orthovoltage X-ray Beams, C M. O'Brien, J.P. McCaffrey, H Shen, M Saravi, G M. Ortiz, G Stefanic, M Carlos, C.N.M. da Silva, J L. Alvarez, V Tovar, Metrologia 52, (2015).
New National Air-Kerma Standard for Low-Energy Electronic Brachytherapy Sources, Stephen M. Seltzer, C M. O'Brien, Michael G. Mitch, NIST JRES 119.022, (2014).
Test Report-Exposure and Ambient dose Equivalent Rate Measurements in Support of the ITRAP+10 Testing, Leticia S. Pibida, Ronaldo Minniti, Larry L. Lucas, C M. O'Brien, NIST TN 1800, (2013).
Key Comparison BIPM.RI(I)-K2 of the air-kerma standards of the NIST, USA and the BIPM in low-energy x-rays, C M. O'Brien, D T. Burns, C Kessler, IOPscience, (2012).
Key comparison BIPM.RI(I)-K7 of the air-kerma standards of the NIST, USA and the BIPM in mammography x-rays, C M. O'Brien, C. Kessler, D T. Burns, Metrologia 0612, (2011).
Efficiency calibrations of cylindrically bent transmission crystals in the 20 keV to 80 keV x-ray range, Lawrence T. Hudson, C M. O'Brien, Uri Feldman, Stephen M. Seltzer, Hye-Sook Park, John F. Seely, Optics Letters 36, (2011).
Validation Testing of ANSI/IEEE N42.49 Standard Requirements for Personal Emergency Radiation Detectors, Leticia S. Pibida, Ronaldo Minniti, C M. O'Brien, Health Physics 98, (2010).
Comparison between the NIST and the KEBS for the Determination of Air kerma Calibration Coefficients for Narrow X-ray Spectra and Cs-137 Gamma-Ray Beams, C M. O'Brien, Ronaldo Minniti, Stanslaus Masinza, NIST JRES 115, (2010).
Comparison of the NIST and PTB Standards for Air Kerma and Low-Energy X-rays, C M. O'Brien, L. Buermann, NIST JRES 114, (2009).
Comparison of national air kerma standards for ISO 4037 narrow spectrum series in the range 30 kV to 300 kV, C M. O'Brien, L. Buermann, P. Butler, I. Csete, F. Gabris, A. Hakanen, J. -. Lee, M. Palmer, N. Saito, W. deViries, Metrologia 45, (2009).
X-Ray and Gamma-Ray Absorbed Dose Profiles in Teeth: An EPR and Modelling Study, S Sholom, C M. O'Brien, E Bakhanova, V Chumak, Marc F. Desrosiers, A Bouville, NIST JRES, (2007).
Comparison of the NIST and BIPM Standards for Air Kerma in Medium-Energy X-Rays, D T. Burns, C M. O'Brien, NIST JRES 111 No. 5, (2006).
NIST Measurement Services: Calibration of X-Ray and Gamma-Ray Measuring Instruments, P. J. Lamperti, and M. O'Brien, Natl. Inst. Stand. Technol. Spec. Publ. 250-58 (Apr. 2001).
Comparison of the NIST and NPL Air Kerma Standards Used for X-ray Measurements Between 10 kV and 80 kV, C M. O'Brien, P J. Lamperti, T T. Williams, Tillman H. Sander, NIST JRES 105 No. 5, (2000).
Comparison of the NIST and BIPM Air-Kerma Standards for Measurements in the Low-Energy X-Ray Range, D T. Burns, P J. Lamperti, C M. O'Brien, NIST JRES 104 No. 2, (1999).
Comparison of Exposure Standards in the Mammography X-Ray Region, J G. Coletti, D W. Pearson, Larry A. DeWerd, C M. O\'Brien, P J. Lamperti, Medical Physics 24, 8 (1997).
Please contact the NIST Technical Contact listed above before sending your equipment for calibration. A shipping address and RMA number will be provided after an order is placed.
$4,915.00