Due to the rapid spread of coronavirus disease 2019 (COVID-19), there is an increasing shortage of protective gear necessary to keep health care providers safe from infection. As of 9 April 2020, the CDC reported 9,282 cumulative cases of COVID-19 among U.S. health care workers (CDC COVID-19 Response Team, MMWR Morb Mortal Wkly Rep 69:477–481, 2020, https://doi.org/10.15585/mmwr.mm6915e6). N95 respirators are recommended by the CDC as the ideal method of protection from COVID-19. Although N95 respirators are traditionally single use, the shortages have necessitated the need for reuse. Effective methods of N95 decontamination that do not affect the fit or filtration ability of N95 respirators are essential. Numerous methods of N95 decontamination exist; however, none are universally accessible. In this study, we describe an effective, standardized, and reproducible means of decontaminating N95 respirators using widely available materials. The N95 decontamination method described in this work will provide a valuable resource for hospitals, health care centers, and outpatient practices that are experiencing increasing shortages of N95 respirators due to the COVID-19 pandemic.

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We describe the construction and operation of an x-ray beam size monitor (xBSM), a device measuring e + and e − beam sizes in the CESR-TA storage ring using synchrotron radiation. The device can measure vertical beam sizes of 10 − 100 µm on a turn-by-turn, bunch-by-bunch basis at e ± beam energies of ∼ 2 GeV. At such beam energies the xBSM images x-rays of ≈1-10 keV (λ ≈ 0.1 − 1 nm) that emerge from a hard-bend magnet through a single-or multiple-slit (coded aperture) optical element onto an array of 32 InGaAs photodiodes with 50 µm pitch. Beamlines and detectors are entirely in-vacuum, enabling single-shot beam size measurement down to below 0.1 mA (2.5 × 10 9 particles) per bunch and inter-bunch spacing of as little as 4 ns. At E b = 2.1 GeV, systematic precision of ∼ 1 µm is achieved for a beam size of ∼ 12 µm; this is expected to scale as ∝ 1/σ b and ∝ 1/E b . Achieving this precision requires comprehensive alignment and calibration of the detector, optical elements, and x-ray beam. Data from the xBSM have been used to extract characteristics of beam oscillations on long and short timescales, and to make detailed studies of low-emittance tuning, intra-beam scattering, electron cloud effects, and multi-bunch instabilities.

1The SARS-CoV-2 pandemic has caused a severe, international shortage of N95 2 respirators, which are essential to protect healthcare providers from infection. Given the 3 contemporary limitations of the supply chain, it is imperative to identify effective means 4 of decontaminating, reusing, and thereby conserving N95 respirator stockpiles. To be 5 effective, decontamination must result in sterilization of the N95 respirator without 6 impairment of respirator filtration or user fit. Although numerous methods of N95 7 decontamination exist, none are universally accessible. In this work we describe a 8 microwave-generated steam decontamination protocol for N95 respirators for use in 9 healthcare systems of all sizes, geographies, and means. Using widely available glass 10 containers, mesh from commercial produce bags, a rubber band, and a 1100W 11 commercially available microwave, we constructed an effective, standardized, and 12 reproducible means of decontaminating N95 respirators. Employing this methodology 13 against MS2 phage, a highly conservative surrogate for SARS-CoV-2 contamination, we 14 report an average 6-log 10 plaque forming unit (PFU) (99.9999%) and a minimum 5-log 10 15 PFU (99.999%) reduction after a single three-minute microwave treatment. Notably, 16 quantified respirator fit and function were preserved, even after 20 sequential cycles of 17 microwave steam decontamination. This method provides a valuable means of effective 18 decontamination and reuse of N95 respirators by frontline providers facing urgent need. 19

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