Hello—

                I’m sorry I missed the call yesterday because of Aerospace AGU dry runs at the same time.  What is the specific question about side penetrators that was asked?  I can dig response functions vs. energy and angle out of my 2010 sensor-head simulations, though I’ll probably have to do it from my hotel room at AGU.  I do intend to port the code to the current version of Geant4 and re-run it, for use in the paper after the one containing the work I’m summarizing on the AGU poster, but for protons the results won’t change much.

--Mark Looper

Mark D. Looper
Space Sciences Department
The Aerospace Corporation
M/S M2-260
P.O. Box 92957
Los Angeles, CA 90009-2957
Mobile: 310-529-3406
Voicemail: 310-336-6302

From: Crater-team <crater-team-bounces@lists.sr.unh.edu> on behalf of Harlan Spence <spence@guero.sr.unh.edu>
Date: Thursday, December 6, 2018 at 10:53 AM
To: Anthony Case <tonycase@cfa.harvard.edu>
Cc: "crater-team@lists.sr.unh.edu" <crater-team@lists.sr.unh.edu>
Subject: Re: [Crater-team] CRaTER Side Shielding

I love it when a plan comes together.  We meant to do that!  I guess it was in the instrument paper for a reason….too many years now.

________________________________

Harlan E. Spence

Director, Institute for the Study of Earth,

   Oceans, & Space and Prof. of Physics 
Morse Hall, Room 306 
University of New Hampshire

8 College Road

Durham, NH 03824-3525

Phone: 603-862-0322

Fax:   603-862-1915

http://www.eos.unh.edu/Faculty/Spence
________________________________

On Dec 6, 2018, at 2:36 PM, Anthony Case <tonycase@cfa.harvard.edu> wrote:

Since we were discussing the possibility of side-penetrators yesterday, I went back and looked at the solid model for the instrument to see how much shielding is on the sides of the detectors.  There are a couple images attached.  The outer wall of the telescope housing is 0.2 cm, and the added shielding was essentially a C-channel with 0.2cm walls that was bolted onto the outside of the telescope housing.  So for normally incident particles there is just the end-caps which are 0.076 cm (which gives us our usual ~10-12 MeV protons required to get into the instrument).  And for side-penetrators to get through a 0.4cm thick wall requires about 27.5 MeV.  That neglects the detector frame, which could add another >0.5 cm.  Of course any particular particle's path through all of this junk is fairly complex, but roughly speaking 30-50 MeV seems like the minimum energy a side-penetrating proton would need to reach the detector.

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---------------------------------------------------------------------

Anthony Case

Astrophysicist

High Energy Astrophysics Division (HEAD/SSXG)

Center for Astrophysics | Harvard & Smithsonian

Cell: (617) 304 0768

60 Garden Street | MS 58 | Cambridge, MA 02138

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