For some reason, the previous two messages from Tancredi and Richard were
not sent to elog nor blast_shifts which I redo now.
MK
---------- Forwarded message ----------
Date: Fri, 5 Mar 2004 12:06:19 -0500 (EST)
From: Richard Milner <milner@mitlns.mit.edu>
To: Tancredi Botto <tancredi@lns.mit.edu>
Cc: John Calarco <jrc@einstein.unh.edu>, Michael Kohl <kohlm@mit.edu>,
"Milner, Richard" <milner@lns.mit.edu>,
"Hasell, Doug" <hasell@lns.mit.edu>,
"Tsentalovich, Genya" <evgeni@mit.edu>,
"Turchinetz, Bill" <billt@lns.mit.edu>
Subject: Re: [BLAST_SHIFTS] [BLAST_ANAWARE] more deadtime
By prescaling the inclusive severely we are left with the central channels
for BLAST (e,e'p) (e,e'n) (e,e'd) for both vector and tensor. The
priority (particularly for the students assigned thesis topics) is to
produce scattering asymmetries from analyzed data. I have seen vector
(e.e'p) asymmetries which tells us the target is vector polarized to about
70%. These results comes in quickly and (if it isn't) should be monitored
at least on a daily basis. We have lots of neutron data (from electrons
detected on the left side until the right side 2nd level trigger was
found unplugged) and (once the neutron offsets are implemented) we should
start to see (e,e'n) vector asymmetries. I have not seen any analysis of
the tensor results that make sense.
In parallel, we must attack the deadtime problem. The (e,e'n) channel is
limiting the livetime. Thus, tightening the electron identification
in this trigger and further lead shielding in front of the forward LADS can
only increase the livetime.
Richard
On Fri, 5 Mar 2004, Tancredi Botto wrote:
>
> While I agree on the big picture here my problem is a lot simpler:
>
> I haven't seen a strong proof of target polarization, we are not at the
> level we were in december, we have had a much more fragmented running so
> far. Nothing wrong, we are just moving on. Should we pursue this by
> throwing away 30% of our first asymmetry data at low Q2 ?
>
> My rationale here is to establish the experiment. I am not taking
> shortcuts, rather I am concerned about "efficacy". Sure I throw away
> stuff: it is just what I want to do to concentrate on the quality of
> the vector and tensor ABS states. Nobody else has measured it, have we ?
>
> I would love to fix the deadtime/2nd level-trigger/beam-tune problem now,
> but I can't. Between now and that moment I think we should maximize the
> reactions that are most important in proving the experiment exists. It
> would also give the strong signal that we want to take data NOW, not
> try another step of development.
>
> Once we make that step I'd be delighted to consider many other
> possibilities. Regards,
>
> tancredi
>
>
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