1. GPAMELA
Alessandro Bruno

2. The PAMELA experiment PAMELA will explore:
Antiproton flux MeV GeV
Positron flux 50 MeV – 270 GeV
Electron flux up to 400 GeV
Proton flux up to 700 GeV
Electron/positron flux up to 2 TeV
Light nuclei (up to Z=6) up to 200 GeV/n
Antinuclei search (sensitivity of 10-7 in He/He)
Alessandro Bruno

3. PAMELA detectors
Main requirements  high-sensitivity antiparticle identification and precise momentum measure
Time-Of-Flight
plastic scintillators + PMT:
Trigger
Albedo rejection;
Mass identification up to 1 GeV;
- Charge identification from dE/dX.
Electromagnetic calorimeter
W/Si sampling (16.3 X0, 0.6 λI)
Discrimination e+ / p, anti-p / e-
(shower topology)
- Direct E measurement for e-
Spectrometer
microstrip silicon tracking system permanent magnet
It provides:
- Magnetic rigidity  R = pc/Ze
Charge sign
Charge value from dE/dx
GF: 21.5 cm2 sr Mass: 470 kg
Size: 130x70x70 cm3
Power Budget: 360W
Alessandro Bruno

4. The GPAMELA code official PAMELA Collaboration simulation program
based on GEANT package 3.21
written in FORTRAN
sequential
CPU intensive
available both in batch and interactive oriented version.
CENLIB and GEANT321 libraries required.
Alessandro Bruno

5. The GPAMELA code
GPAMELA allows to simulate particles and reproduce their interaction within the PAMELA instrument.
Hadronic Packages:
GHEISHA
FLUKA
GCALOR
DPMJET (nuclei)
Alessandro Bruno

6. The GPAMELA code
The main program allocates the dynamic memory for ZEBRA and
HBOOK and passes control to the three phases of the run:
initialization (reads user datacard, creates geometry, initializes histograms, etc. )
event processing (generates events, tracks particles, etc.)
termination (computes, prints some statistical information, etc.)
where in each of the three phases appropriate routines
have been implemented.
Alessandro Bruno

7. GPAMELA: INPUT CARDS
GEOMETRY AND MATERIALS (detectors activation, tracking parameters…)
BEAM PROPERTIES (energy, direction, generation surface, …)
PHYSICS (packages, processes, cuts, …)
HBOOK (output)
RUN CONTROL (random seeds, #events, #run, ...)
Alessandro Bruno

8. GPAMELA: THE HIT STRUCTURE
scintillator
To each detector is associated a hit structure containing all variable about the particle passage (energy loss, position, particle type, time of flight, etc.)
Alessandro Bruno

9. GPAMELA: HBOOK OUTPUT
The GPAMELA output consists of an hbook ntuple containing all variables concerning the particle passage in each detector (for example released energy etc.etc.).
Output analysis is performed in the PAW framework.
Additional digitization software is available to the user in order to have access to the entries in the GPAMELA ntuple and calculate from the variables contained therein PAMELA raw data, which is filled in some data members.
Alessandro Bruno

10. PARAMETRIC JOB
[ JobType = "Parametric"; Executable = "/bin/sh"; Arguments = "gpamela_grid.sh _PARAM_"; InputSandbox={"gpamela_grid.sh","list_infosites.txt"}; Parameters= 301; ParameterStep = 1; ParameterStart = 1; StdOutput = "my_gpamela_pions_PARAM_.out"; StdError = "my_gpamela_pions_PARAM_.err"; OutputSandbox = {"my_gpamela_pions_PARAM_.out", "my_gpamela_pions_PARAM_.err"}; ShallowRetryCount = 1; ]
Alessandro Bruno

11. PARAMETRIC JOB read a b c d < list_infosites.txt
#!/bin/bash
export ALEXHOME=`pwd`
lcg-cp --vo gilda lfn:/grid/gilda/alexdirectory/my_gpamela_pions.tar file://$ALEXHOME/my_gpamela_pions.tar
tar -xvf //$ALEXHOME/my_gpamela_pions.tar
cd $ALEXHOME/my_gpamela_pions
./run_gpamela.sh $1
OUT="output_$1“
if [ -d "$OUT" ];
then
echo "directory $OUT already exists“
else
mkdir $OUT
echo "directory $OUT created“ fi
mv *.his $OUT
tar cf output_$1.tar $OUT
read a b c d < list_infosites.txt
lcg-cr --vo gilda file://$ALEXHOME/my_gpamela_pions/output_$1.tar -l lfn:/grid/gilda/alexdirectory/output_$1.tar -d $d
Alessandro Bruno

12. PARAMETRIC JOB #!/bin/bash var0=1 LIMITE=1 NRUN=1 NEVN=1 NTOT=1000000
while [ "$var0" -lt "$LIMITE" ] do
var0=`expr $var0 + 1`
NRUN=`expr $NRUN + 1`
NEVN=`expr $NEVN + $NTOT`
./gppions.exe <<EOF
read 4
*HBFI 11 'step2_$1_$var0.HIS‘
kine
trig $NTOT
HFSF 2
RUNG 1=$NRUN 2=$NEVN
*FSFI 14 'STEP2_SEEDS_$1.DAT‘
*LSFI 15 'STEP2_SEEDS_$1.DAT‘
end
EOF
done
Alessandro Bruno