On Wed, Apr 7, 2010 at 1:55 PM, Brad Sawatzky <<a href="mailto:brads@jlab.org">brads@jlab.org</a>> wrote:<br><div class="gmail_quote"><blockquote class="gmail_quote">
<div>On Tue, 06 Apr 2010, David Flay wrote:<br>
<br>
> So I've been investigating the THaScintillator class for how the analyzer<br>
> implements the coefficients.<br>
><br>
> I found in the ApplyCorrections member function:<br>
><br>
> if (fLT[i] != 0.) {<br>
> fLT_c[i] = (fLT[i] - fLOff[i])*fTdc2T - TimeWalkCorrection(i,kLeft);<br>
> nlt++;<br>
> }<br>
> if (fRT[i] != 0.) {<br>
> fRT_c[i] = (fRT[i] - fROff[i])*fTdc2T - TimeWalkCorrection(i,kRight);<br>
> nrt++;<br>
> }<br>
><br>
> Where fTdc2T = resolution of the TDC = 0.1e-9 s/channel.<br>
<br>
</div>This is only true for an 1875. I don't think we used that model TDC.<br>
Make sure the this resolution number corresponds to the TDC you're<br>
getting your data from.<br></blockquote><div><br>Are you talking about just the resolution, or the calculation as well?<br><br>I've been searching through my various timestamped directories, and they all say 1875. However, I'm not totally confident in that, because I created 'master' db_L.s1.dat, db_L.s2.dat files based off of run 20676 (20090313 directory) and copied those to each and every other directory (once I figured out that the cratemap was wrong).<br>
<br>Also -- I fear that maybe the true TDC model # was lost when Matt and I created the merged DB back in September -- however, even my earliest backup shows 1875. In which case, I've asked Vince. <br> <br></div><blockquote class="gmail_quote">
<br>
[ . . . ]<br>
<div>> now, the ReadDatabase() member function does:<br>
><br>
> // timewalk coefficients for tw = coeff*(1./sqrt(ADC-Ped)-1/sqrt(ADCMip))<br>
> for (int i=0; i<fNTWalkPar; i++) fTWalkPar[i]=0;<br>
><br>
> ADCMip is a very large number, so we don't need to worry about it, as<br>
> 1/sqrt(ADCMip) ~ 0.<br>
<br>
</div>What is ADCMip supposed to represent? It must be some holdover from<br>
ancient times... Its function seems far better handled by the t0<br>
offsets...<br></blockquote><div><br>All I could find in the THaScintillator class is:<br><br> // Time-walk correction parameters<br> fAdcMIP = 1.e10; // large number for offset, so reference is effectively disabled<br>
<br><br></div></div><br><br clear="all"><br>-- <br>-----------------------------------------------------------<br>David Flay<br>Physics Department<br>Temple University<br>Philadelphia, PA 19122 <br><br>office: Barton Hall, BA319<br>
phone: (215) 204-1331<br><br>e-mail: <a href="mailto:flay@jlab.org">flay@jlab.org</a> <br> <a href="mailto:flay@temple.edu">flay@temple.edu</a><br><br>website: <a href="http://www.jlab.org/%7Eflay">http://www.jlab.org/~flay</a><br>
<a href="http://quarks.temple.edu">http://quarks.temple.edu</a><br>-----------------------------------------------------------<br><br><br>