From richard@stars.gsfc.nasa.gov Tue Mar 18 11:06:10 2003
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From: "Richard Schwartz" <richard@stars.gsfc.nasa.gov>
To: "Hugh Hudson" <hhudson@ssl.berkeley.edu>
References: <200303181727.h2IHRFw00266@delsol.ssl.berkeley.edu>
Subject: Re: individual detectors
Date: Tue, 18 Mar 2003 14:06:08 -0500
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Status: R

Hugh

It's easy to get the average livetime weighted grid transmission.  First get
the roll period from an observing summary object:

IDL> temp=obs->getdata(class='hsi_qlook_roll_period')
IDL> roll=avg(temp.roll_period)
IDL> print,roll
4.08838
Next, set the time_range in an imaging object to some integral number of
roll periods for the appropriate obs_time_interval:
IDL> im->set,time_range=[0,roll*10]
Extract the calib_eventlist and compute:
IDL> c=im->getdata(class='hsi_calib_eventlist')
HSI_RD_RASPMT: 56 packets of PMTRAS data were found.
PMTRAS_ANALYSIS: Blip intensity cutoff set to 94
PMTRAS_ANALYSIS: Compensating for P-angle = -12.083 degrees
PMTRAS_ANALYSIS: 1667 points. Period= 4.088239 s 6 stars MAXrmsscatter=
0.032 degrees.
IDL>
IDL> for i=0,8 do print,avg( (*c[i]).gridtran)
0.174087
0.177655
0.122889
0.187994
0.165717
0.201592
0.223310
0.217403
0.218618
IDL> for i=0,8 do print,avg( (*c[i]).gridtran *(*c[i]).livetime)
0.170131
0.172686
0.119922
0.183611
0.161839
0.196923
0.218630
0.212284
0.213727

So you see there is a good explanatio for the smaller amplitude of 3.  This
is the first Van Beek grid and fov is a problem for finer grids of this
design.

Richard
----- Original Message -----
From: "Hugh Hudson" <hhudson@ssl.berkeley.edu>
To: <richard@stars.gsfc.nasa.gov>
Cc: <Brian.R.Dennis@nasa.gov>; <hhudson@delsol.ssl.berkeley.edu>
Sent: Tuesday, March 18, 2003 12:27 PM
Subject: Re: individual detectors


> Hmmm, you're right about the slow modulation, I was not thinking about
> that. We seem not to be limited very strongly by photon count in A0
> (surprise, surprise) so maybe the best bet is to stick with whichever
> of G6, G8, or G9 have small slow modulation.
>
> More anon
>
> Hugh