Real-Time Monitoring of Solar Energetic Particles Using the Alpha Magnetic Spectrometer on the International Space Station

Round 1

Reviewer 1 Report

This paper provides a compact outline of the design and use of the Alpha Magnetic Spectrometer (AMS) installed on the International Space Station (ISS) to monitor bursts of Solar Energetic Particles (SEP) with energies spanning 10s of keV to several GeV. The presentation in the paper focuses especially on data handling strategies and various rationales for instrument component designs and associated strategies to facilitate accurate recognition of SEP bursts and their properties. The presentation level is suitable to introduce the AMS to readers with a general interest in the requirements for such a monitoring system in low earth orbit. It does not, nor is it evidently intended to lay out instrumental technical design issues at a level that would target an audience of instrument design experts or individuals aiming to understand the physics of SEP generation or propagation from the sun.

The English is mostly pretty good. There are a few minor scattered English language issues that should be corrected before publication. I recommend that the authors get comments from a native English speaker on their final draft. I do point out for correction the statement on page 1 "The ISS is not completely shielded from the cosmic radiation and during extra-vehicular activities the exposition is high." As written the sentence makes no sense.  The word "exposition" probably should be "exposure". That would make sense.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

This paper describes the use of data produced by the Alpha Magnetic Spectrometer (AMS) on the International Space Station (ISS) to develop a monitoring system to identify solar energetic particle (SEP) events in close to real time.  This would be a service to ISS users who require radiation protection or need to know the current state of the ISS radiation conditions.  The paper points the way to an automated on-board system through the present system which currently requires analysis outside the ISS and is subject to limitations of data flow. The paper is generally clearly written.  Some minor 'english' expression issues remain, but none should confuse a reader.  The paper is publishable with some minor modifications to help the reader.  The supplementary materials clarify a number of issues for a reader viewing the paper for the first time and reference could be made within the text.

The Conclusions usefully indicate where this work sits in developing a future local ISS SEP warning system.  This is a useful result.

Some comments for the authors to consider:

A general reference for AMS-02 would be welcome in the introduction.

"FTZ, FTC, FTE" are important in the paper, and their existing descriptions need brief expansions.  For instance, "Fast Trigger ECAL" is mysterious to a reader.  This may be in a general AMS reference as above.

Equation 1 has a live-time term.  This is shown clearly in the supplementary material but not in the main text.  Either indicate some representative values in the text or reference the supplementary material.

Figure 2 is useful and shows some important features but is not clear to a first time reader.  There are white dots in places, although one does see the general idea of the Figure.  Maybe rethink the display of this figure related to what the reader should take away.

Equation (3) derives a score - s - through f, a PDF.  The reader needs some better understanding (a better description) of s so that the key figures 4, 5 can be better understood.  What values of s might be expected for a likely signal or background?

It may be intuitively obvious, but the reason that the condition L>1.5 Ro (line 168, Figure 5) is effective at removing noise warrants a sentence, I think.

As noted above.  The 'English' is quite acceptable.  It issometimes not as found from a native speaker, but no confusions result.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf