Gams reconstruction
Short description of the reconstruction package developed for GAMS
(with changes and updates)
Code location:
svn ls https://halldsvn.jlab.org/repos/trunk/Studies/eta/gams
Package includes:
adcgam_bk.inc common with output reconstruction
phot_cell_cbk_mc.inc common with shower profile parameters
cphoto.inc common with control keys, flags and other aux. variables
addhits_lib.F generates hits based on shower library data
addhits_sim.F performs hits generation using fast simulation based on profile functions
isim.F main routine calling others to generate hits
recon_sim.F contains reconstruction package itself
guout.F call recon_sim() from here to get event reconstruction
gustep.F call isim(chdet,chsimopt) to simulate and store hits. Normally, after that particle stops in GUSTEP (ISTOP = 1) to avoid multiple counting
Files description:
adcgam_bk.inc Reconstruction common looks like:
Real:
energy_adcgam(1,i) - energy in GeV
x_adcgam(1,i) - log. method x-coord (angular correction applied)
y_adcgam(1,i) - log. method y-coord (angular correction applied)
z_adcgam(1,i) - z-coord
xc_adcgam(1,i) - center of gravity x-coord (no angular correction and global alignment - internal ref. syst.)
yc_adcgam(1,i) - center of gravity y-coord (no angular correction and global alignment - internal ref. syst.)
chi2_adcgam(1,i) - chi2
Integer:
type_adcgam(1,i) - type of the gamma: = 0 default value += 1 or 2 for clusters selected by splitting single maxima shape += 10 for clusters selected from mutlimaxima island += 100 for LG clusters in hybrid detector = 50 + type1 + type2 for merged together subclusters 1 and 2 (transition case)
(hole size is hardcoded to 5x5 cells for PWO and 3x3 cells for LG)
dime_adcgam(1,i) - number of counters in the gamma id_adcgam(1,i) - id of the cell with the max energy deposition: = 10*col+row nadcgam - number of reconstructions in event (i = 1 ... nadcgam)
isim.F - control keys and options:
chdet = hybrid or lg, - simulate Hybrid (120x120cm pwo and LG outer part) or "regular" LG FCAL
chsimopt = simfast, libr or libs for fast profile simulation or to read clusters from library (sequentially or randomly)
addhits_sim.F and addhits_lib.F:
generate response for
e+/e-/gamma - library read or simfast,
other types - for now simfast only:
MIP - gaussian energy deposition in single cell
neutral hadrons - parametrized ugly shape from GAMS,
probab. of shower is given by nulc. length
charged hadrons = neutral hadrons + MIP
isim.F - flags and options:
zmcplane = 625.0506cm - FCal upstream surf. z
main settings are in init_sim_geom (file isim.F):
min_energy = 0.1 - [GeV] clusters energy threshold
global_gain= 1.000 - global energy gain, useful to quickly correct energy scale
delch = 4. - minimum chi2 improvement sufficient for algorithm to decide to split 2 clusters from the signle maximum shape
xm2cut = 1.2 - min inv. mass over e cut to split hits
minpk = 9 - (in 10MeV units) minimum cell energy to be good for the peak of the island, note that this cut indirectly affects on cluster min energy
chisq1 = 3 - min chi2 to try to split shape at preliminary stage
chisq2 = 1.4 (was 0.4) - min chi2 to try to split shape at final stage
event_display = 0 - whether to run event display (option removed to allow hybrid)
Some things to be done:
*) implement shower library for LG *) restore Event Display for hybrid option *) switch from chi2 to loglikelihood in reoncstruction *) introduce chi2x and chi2y for x and y reconstruction *) switch from rndm,rannor,etc to grndm,granor,etc
Other things which could / should be useful:
*) timing information usage *) improve MIP and hadronic simulations *) MC matching
