Re: Understanding PDE information (fwd)

[Elke-Caroline Aschenauer <elke@jlab.org>]

Date: Wed, 18 Apr 2007 17:03:16 -0400 (EDT)
From: Elke-Caroline Aschenauer <elke@jlab.org>
To: Richard Jones <richard.t.jones@uconn.edu>
Cc: George J. Lolos <George.Lolos@uregina.ca>, Elton Smith <elton@jlab.org>,
     halld_cal@jlab.org
Subject: Re: Understanding PDE information

On Wed, 18 Apr 2007, Richard Jones wrote:

hm, I'm not sure that is the way to go at the moment. Because what ever we
compare we have no array of 1.2 * 1.2 cm^2 as George pointed out. And
sometimes not even a way to get an array of the desired size. Which
means if we are only interested in the performance of what we want to buy
we know nothing at the moment.
That is a possible strategy, but not very helpful to come to some
conclusions till the end of the month.
Actually the logical consequence of this is to increase the risk-factor
for the readout of the bcal and the UPV by the way, which needs the SiPMT
arrays as well. If we can avoid this we should really do so.

We will discuss this more a lot more next week :)

cheers elke




> Date: Wed, 18 Apr 2007 16:45:40 -0400
> From: Richard Jones <richard.t.jones@uconn.edu>
> To: Elke-Caroline Aschenauer <elke@jlab.org>
> Cc: George J. Lolos <George.Lolos@uregina.ca>, Elton Smith <elton@jlab.org>
> Subject: Re: Understanding PDE information
>
> Dear Elke,
>
> Fill-factor is important from the viewpoint of the manufacturer, but for
> the detector builder I claim that only the PDE is relevant.  From what I
> understand, there are trade-offs in device performance between fill
> factor and QE/DR optimization so we cannot assume that fill factor can
> be increased without compromise in some other area of the performance.
> In our discussion I think we should leave manufacturer's details aside
> and only speak of actual performance characteristics: PDE, DR at a
> certain temperature and bias over-voltage.  This is what Carl has done,
> and what I seek to do in my comparison.
>
> Richard J.
>
> Elke-Caroline Aschenauer wrote:
> > On Wed, 18 Apr 2007, Richard Jones wrote:
> >
> > Dear Richard,
> >
> > I think we have to be careful again comparing numbers.
> > the PDE depends on the breakdown voltage (carls talk page 11 not counting overlays), which you have taken care of in your comparision, but it also depends on the fill factor (zisis talk page 5 and 7)
> >
> > PDE = Q_E*alpha*F
> >
> > so what is the fill factor for your Photonique SiPMTs and than you have 2mm x 2mm active area and the ones from carl a 1mm x 1mm, I think we should also account for this, like Carl does in his eq on page 9.
> >
> > Maybe I'm wrong.
> >
> > Cheers elke
> >
>
>

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