Use of a Mylar filter to eliminate vacuum ultraviolet pulse pileup in low-energy x-ray measurements
Abstract
We describe a method to reduce vacuum ultraviolet (VUV) pulse pileup (PPU) in x-ray pulse-height Silicon Drift Detector (SDD) signals. An Amptek FAST SDD, with C1 (Si3N4) window, measures bremsstrahlung emitted from PFRC-2 plasma to extract the electron temperature (Te) and density (ne). The C1 window has low transmissivity for photons with energy below 200 eV though will transmit some VUV and soft x-ray photons, which PFRC-2 plasmas abundantly emit. Multi-VUV-photon PPU contaminates the interpretation of x rays with energy > 100 eV, particularly in a low-energy exponential tail. The predicted low transmissivity of ~1 μm thick Mylar [polyethylene terephthalate (PET)] to photons of energy <100 eV led to the selection of Mylar as the candidate filter to reduce VUV PPU. Experiments were conducted on an x-ray tube with a graphite target and on a quasi-Maxwellian tenuous plasma (ne ~ 109 cm–3) with effective temperatures reaching 1500 eV. A Mylar filter thickness of 850 nm is consistent with the results. The Mylar-filter-equipped SDD was then used on the PFRC-2 plasma, showing a substantial reduction in the low-energy x-ray signal, supporting our hypothesis of the importance of VUV PPU. Here, we describe the modeling and experiments performed to characterize the effectmore »
- Authors:
-
[1];
[2];
[2];
- Princeton Fusion Systems, Inc., Plainsboro, NJ (United States)
- Princeton Univ., NJ (United States)
- Publication Date:
- Research Org.:
- Princeton Fusion Systems, Inc., Plainsboro, NJ (United States)
- Sponsoring Org.:
- USDOE Advanced Research Projects Agency - Energy (ARPA-E)
- OSTI Identifier:
- 1890157
- Alternate Identifier(s):
- OSTI ID: 1890515
- Grant/Contract Number:
- AR0001099; AC02-09CH11466
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Review of Scientific Instruments
- Additional Journal Information:
- Journal Volume: 93; Journal Issue: 9; Journal ID: ISSN 0034-6748
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Electron energy distribution functions; Vacuum ultraviolet radiation; Electronic shell; X-ray spectroscopy; Interferometry; Polymers; Bremsstrahlung; Vacuum tubes; Electromagnetic radiation detectors
Citation Formats
Galea, Chris A., Swanson, C. S., Cohen, S. A., and Thomas, Stephanie J. Use of a Mylar filter to eliminate vacuum ultraviolet pulse pileup in low-energy x-ray measurements. United States: N. p., 2022.
Web. doi:10.1063/5.0101712.
Galea, Chris A., Swanson, C. S., Cohen, S. A., & Thomas, Stephanie J. Use of a Mylar filter to eliminate vacuum ultraviolet pulse pileup in low-energy x-ray measurements. United States. https://doi.org/10.1063/5.0101712
Galea, Chris A., Swanson, C. S., Cohen, S. A., and Thomas, Stephanie J. Fri .
"Use of a Mylar filter to eliminate vacuum ultraviolet pulse pileup in low-energy x-ray measurements". United States. https://doi.org/10.1063/5.0101712. https://www.osti.gov/servlets/purl/1890157.
@article{osti_1890157,
title = {Use of a Mylar filter to eliminate vacuum ultraviolet pulse pileup in low-energy x-ray measurements},
author = {Galea, Chris A. and Swanson, C. S. and Cohen, S. A. and Thomas, Stephanie J.},
abstractNote = {We describe a method to reduce vacuum ultraviolet (VUV) pulse pileup (PPU) in x-ray pulse-height Silicon Drift Detector (SDD) signals. An Amptek FAST SDD, with C1 (Si3N4) window, measures bremsstrahlung emitted from PFRC-2 plasma to extract the electron temperature (Te) and density (ne). The C1 window has low transmissivity for photons with energy below 200 eV though will transmit some VUV and soft x-ray photons, which PFRC-2 plasmas abundantly emit. Multi-VUV-photon PPU contaminates the interpretation of x rays with energy > 100 eV, particularly in a low-energy exponential tail. The predicted low transmissivity of ~1 μm thick Mylar [polyethylene terephthalate (PET)] to photons of energy <100 eV led to the selection of Mylar as the candidate filter to reduce VUV PPU. Experiments were conducted on an x-ray tube with a graphite target and on a quasi-Maxwellian tenuous plasma (ne ~ 109 cm–3) with effective temperatures reaching 1500 eV. A Mylar filter thickness of 850 nm is consistent with the results. The Mylar-filter-equipped SDD was then used on the PFRC-2 plasma, showing a substantial reduction in the low-energy x-ray signal, supporting our hypothesis of the importance of VUV PPU. Here, we describe the modeling and experiments performed to characterize the effect of the Mylar filter on SDD measurements.},
doi = {10.1063/5.0101712},
journal = {Review of Scientific Instruments},
number = 9,
volume = 93,
place = {United States},
year = {Fri Sep 30 00:00:00 EDT 2022},
month = {Fri Sep 30 00:00:00 EDT 2022}
}
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