Subject: Re: draft of the Combined Monopole Analysis paper: read/correct it
From: Ivan De Mitri (ivan.demitri@le.infn.it)
Date: Tue Sep 19 2000 - 06:40:38 EDT
Dear Erik,
here follows the list of answers to your questions/comments
about the technical paper on the combined fast monopole analysis.
Ivan & Fausto
1) Of course we use the standard calibrations.
Essentially in the paper we wrote that:
- the non-linear effects due to the PMT, ADC, and so on
are corrected by means of the laser
- the absolute energy calibration is performed by
means of the muon peak.
Yes you are right, this procedure is done for non-attenuated ADC only,
therefore the sentence you refer to has to be changed to make this
clear.
Please note that in the analysis none of the non-linearity
corrections is used, since we put the energy cut well below
the saturations. Fig.4 is reported just to show that this effect
exist and that our cut is below the non-linear regime.
2) This cut is actually present because if at least two
ERP boxes are present, we can also reconstruct the ToF
of the particle. This quantity can be used, if necessary,
to reject possible candidates by looking at the dE/dX vs
beta plot. Moreover, it has to be taken into account that
this cut has a large correlation with the cut on the hit
position along the box.
Furthermore, given the saturations, above 150 MeV (which is
the region in which we look for candidates) the dynamic range
is not so large.
Finally there are no cuts on the number of ERP boxes actually
fired: of course we need at least one fulfilling the selection
criteria.
3) The 60ns is somehow a measurement of the signal fall time
(the box crossing time for muons is of course irrelevent).
For slower particles the pulse duration should be equal to
the box crossing time + the signal fall time.
Given that, we think that the text is pretty clear.
4) You obtain ~ 1GeV since you do not take into account the
factor two uncertanty quoted in the Ahlen-Tarle' paper.
Therefore in the worst case, which is what has to be
considered in estimating the analysis efficiency, one must
take into account this factor 2 (--> 470 MeV).
5) This is something that we judge not stricly necessary.
We did not include it also because of problems with paper
length. The editorial board will judge on that.
6) As far as eq.4 is concerned we took the (dE/dx)min from
the PDG by considering the energy loss of muons in carbon
at the minimum of the Bethe-Block curve (1.8 MeV/gcm2).
If we take the de/dx of muons with energy equal to the
average energy of the atmospheric muons we have in MACRO
(i.e. ~ 200 GeV) we opbtain ~ 2.1-2.2 MeV/gcm2 which
is compatible (throught the 0.86g/cm3 density of the scint.)
with the 1.8 MeV/cm.
I agree with you that we have to fix this number. I would be
nice to have a copy of the technical paper you quote.
This numbers can be put in the paper once we agree on that.
In practice this has no consequence on the analysis, since
going from 1.8MeV/gcm2 to 2.1MeV/gcm2 even raise the efficiency
of the 150 MeV cut. See item 11 for Fig.3
7) You are right as far as the caption of Fig.10 is concerned.
We already corrected that.
You have to take into account that our estimation of the
global 'ERP' efficiency includes also all the tracking
possible mismatches.
It might be underestimated, however everywhere in the analysis
we decided to be conservative.
8) Of course this is in a window of a couple of meters around
the center of the tank. This is not written in the text since
in a previous version there was a figure with this information
in the caption. I agree with you that it should be written now.
9) This plot could have been inserted in the paper. We decided not to
do it for "lenght" problems. Also in this case the editorial
board will see.
10) The acceptance is obtained with a FULL simulation done with
GMACRO including everything.
The CR39 contribution is also included. This is however a very
little contribution since the analysis requires the Streamer
Horizontal Monopole Trigger.
The detector configuration (number of active uVax's, and so on)
depends on the run number. This is taken into account in the
efficiency evaluations.
11) Yes the correct axis should be in MeV/cm.
Since we have paper lenght problems, and since (as you stressed)
this is an issue of the forthcoming technical paper, we can decide
to cut this Fig. 3 out.
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