Physical Review Special Topics. Accelerators and Beams (Nov 2006)

Measurement of the energy and power radiated by a pulsed blackbody x-ray source

  • H. C. Ives,
  • W. A. Stygar,
  • D. L. Fehl,
  • L. E. Ramirez,
  • S. C. Dropinski,
  • D. L. Wall,
  • J. S. Anctil,
  • J. S. McGurn,
  • J. H. Pyle,
  • D. L. Hanson,
  • B. N. Allison,
  • M. J. Berninger,
  • E. A. Bryce,
  • G. A. Chandler,
  • M. E. Cuneo,
  • A. J. Fox,
  • T. L. Gilliland,
  • C. L. Haslett,
  • R. J. Leeper,
  • D. F. Lewis,
  • M. A. Lucero,
  • M. G. Mazarakis,
  • D. H. McDaniel,
  • J. L. McKenney,
  • J. A. Mills,
  • L. P. Mix,
  • J. L. Porter,
  • M. B. Ritchey,
  • L. E. Ruggles,
  • J. F. Seamen,
  • W. W. Simpson,
  • R. B. Spielman,
  • J. A. Torres,
  • M. F. Vargas,
  • T. C. Wagoner,
  • L. K. Warne,
  • M. W. York

DOI
https://doi.org/10.1103/PhysRevSTAB.9.110401
Journal volume & issue
Vol. 9, no. 11
p. 110401

Abstract

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We have developed a diagnostic system that measures the spectrally integrated (i.e. the total) energy and power radiated by a pulsed blackbody x-ray source. The total-energy-and-power (TEP) diagnostic system is optimized for blackbody temperatures between 50 and 350 eV. The system can view apertured sources that radiate energies and powers as high as 2 MJ and 200 TW, respectively, and has been successfully tested at 0.84 MJ and 73 TW on the Z pulsed-power accelerator. The TEP system consists of two pinhole arrays, two silicon-diode detectors, and two thin-film nickel bolometers. Each of the two pinhole arrays is paired with a single silicon diode. Each array consists of a 38×38 square array of 10-μm-diameter pinholes in a 50-μm-thick tantalum plate. The arrays achromatically attenuate the x-ray flux by a factor of ∼1800. The use of such arrays for the attenuation of soft x rays was first proposed by Turner and co-workers [Rev. Sci. Instrum. 70, 656 (1999)RSINAK0034-674810.1063/1.1149385]. The attenuated flux from each array illuminates its associated diode; the diode’s output current is recorded by a data-acquisition system with 0.6-ns time resolution. The arrays and diodes are located 19 and 24 m from the source, respectively. Because the diodes are designed to have an approximately flat spectral sensitivity, the output current from each diode is proportional to the x-ray power. The nickel bolometers are fielded at a slightly different angle from the array-diode combinations, and view (without pinhole attenuation) the same x-ray source. The bolometers measure the total x-ray energy radiated by the source and—on every shot—provide an in situ calibration of the array-diode combinations. Two array-diode pairs and two bolometers are fielded to reduce random uncertainties. An analytic model (which accounts for pinhole-diffraction effects) of the sensitivity of an array-diode combination is presented.