From ssm@latte.msfc.nasa.gov Fri Mar 21 01:51:39 1997 Received: from space.mit.edu by wiwaxia AA01619; Fri, 21 Mar 97 01:51:37 EST Received: from head-cfa (head-cfa.harvard.edu) by space.mit.edu AA01324; Fri, 21 Mar 97 01:51:35 EST Received: from latte.msfc.nasa.gov by head-cfa (SMI-8.6/SMI-SVR4) id BAA11916; Fri, 21 Mar 1997 01:50:19 -0500 Received: from latte.msfc.nasa.gov (ssm@localhost [127.0.0.1]) by latte.msfc.nasa.gov (8.7.5/8.7.3) with ESMTP id BAA18447; Fri, 21 Mar 1997 01:52:37 -0500 Message-Id: <199703210652.BAA18447@latte.msfc.nasa.gov> To: head@head-cfa.harvard.edu Cc: martin@smoker.msfc.nasa.gov Subject: HRC Status #2 Date: Fri, 21 Mar 1997 01:52:37 -0500 From: "Stephen S. Murray" Status: R The HRC-I continues to behave very well. We have completed a series of effective area tests (sorry no results as yet) and have gone into the detailed focus measurements using the HRMA shutters and the HRC Knife Edges. Shutter tests place the HRC within 1mm of the "true" HRMA focus with a determination good to about 150microns. We will soon be placing the HRC into this focus and conducting a series of count rate linearity tests to tell us the maximum allowed count rate for in focus sources. Background checks still show about 2.6 cts/sec (which by the way translates to less than 1 ct/square arc second/ fortnight). No hot spots nor warm spots are seen. There appears to be more gain non-uniformity across the entire HRC-I with a focused beam than we saw with our flat field tests. This will require further examination and we may need to adjust our MCP voltages. Right now the center of the detector shows higher gain than we would like, resulting some events saturating the electronics. We can (and do) screen out these events from processing, but the result is decreased (slightly) effective quantum efficiency. We have been transferring data from the HRC EGSE up to the third floor and to the ASC on a regular basis (one day per day) and so all of the data is being looked at by the combined HRC and ASC teams quickly. Once we have worked out the startup kinks, we expect to transfer data every few hours making quick look analysis go faster. One result of this rapid data transfer was the discovery and remedy for dealing with events that have a saturated amplifier output. We also have a quick estimate of the effective area of the HRC at about 2.5 keV. Without being too quantitative - since we have not done a very good job with the BND data yet - we find decent agreement with the expected throughput (within about 20%) indicating that the detector CsI coating is holding up. We will need some time to get these results refined, and to extend the analysis to all energies. I hope to put together some nice composite images of the quadrant focus sometime tomorrow for your viewing pleasure. Steve Dr. Stephen S. Murray - Sr. Astrophysicist Associate Director - High Energy Astrophysics Division _______________________________________*_______________________________________ Smithsonian Astrophysical Observatory__| phone: (617) 495-7205 High Energy Astrophysics Division __| fax: (617) 495-7356 60 Garden Street, MS-2 __| email: ssm@head-cfa.harvard.edu Cambridge, MA 02138 __| http://hea-www.harvard.edu/~ssm/HomePage.html ___________________________|___________________________________________________