1. Narrow Line X-Ray Calibration Source for High Resolution Microcalorimeters
- Author
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Kelsey M. Morgan, Sang Jun Lee, M. S. Hokin, Simon R. Bandler, Samuel H. Moseley, D. McCammon, and Stephen J. Smith
- Subjects
Physics ,Laser diode ,business.industry ,Detector ,X-ray detector ,Condensed Matter Physics ,Laser ,Atomic and Molecular Physics, and Optics ,Semiconductor laser theory ,law.invention ,Full width at half maximum ,Optics ,law ,Optoelectronics ,General Materials Science ,Photonics ,business ,Diode - Abstract
We are developing a narrow line calibration source for use with X-ray microcalorimeters. At energies below 300 electronvolts fluorescent lines are intrinsically broad, making calibration of high resolution detectors difficult. This source consists of a 405 nanometers (3 electronvolts) laser diode coupled to an optical fiber. The diode is pulsed to create approximately one hundred photons in a few microseconds. If the pulses are short compared to the rise time of the detector, they will be detected as single events with a total energy in the soft X-ray range. Poisson fluctuations in photon number per pulse create a comb of X-ray lines with 3 electronvolts spacing, so detectors with energy resolution better than 2 electronvolts are required to resolve the individual lines. Our currently unstabilized diode has a multimode width less than 1 nanometer, giving a 300 electronvolt event a Full width at half maximum (FWHM) less than 0.1 electronvolts. By varying the driving voltage, or pulse width, the source can produce a comb centered on a wide range of energies. The calibration events are produced at precisely known times. This allows continuous calibration of a flight mission without contaminating the observed spectrum and with minimal deadtime.
- Published
- 2013