My analysis so far agrees with Genya's results on both counts, namely:
1. The rates seem to be linear with increased target thickness yet
sloping downwards as the
shown at the last meeting indicated.
2. The rates are over 30% higher for the set of runs at the end of
running for which we allegedly
switched back to 100mA max fill current.
n
Genya wrote:
>
> Dear all,
> First, I have to say that my claim about huge drop of the rate at
> the unpol run with increased
> target density was wrong. As it turned out, I used wrong run numbers.
> Now I'd like to present a clarified picture. eD elastic events are
> used for retes.
> 1. Target density dependence in unpol runs.
> a) normal density (Pbuf=2 torr) R=793+-6 events/kC
> b) Pbuf = 1 torr R=424+-6
> (expected - 397)
> c) Pbuf = 3 torr
> R=1160+-12 (expected -1190)
> One may note, that with reduced target thickness, rate is a bit
> higher than expected, and at
> high density rates are smaller than expected. Not by much, but ourside
> error bars. I believe,
> Nick observed similar picture in inclusives.
> 2) Current dependence in ABS runs, the target is at the same state
> (age?) for both runs.
> a) normal conditions (Imax~230 mA) R=674+-7
> b) Imax=100mA R=904+-9
> Here the effect is much more dramatic. At low current rates a MUCH
> higher.
> The only reasonable explanation I can come up witth is that wire
> chamberrs efficiency (or, rather,
> efficiency of reconstruction) depends on the wire chambers rate, and
> that during our "normal" conditions
> this efficiency is less than 75%. With low current, the chambers rate
> drops very drastically, and changes
> in target thickness have much smaller effect.
> Genya
>
>
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