[Gate-users] Error message: Nof higher level 5

Albert Hirtl albert.hirtl at meduniwien.ac.at
Fri Jun 17 15:21:07 CEST 2011


Hello Gate community!

My name is Martin Jankovec, I'm a master student in technical physics 
(the mail is written by Albert since my account has not yet been 
activated :-) ).
In my Gate code a little error occurred, that I can't explain:

First, here is my code (the question is below):

-----------------------------------------------------------------------------------------------------------
#
###### VISUALISATION ######################

/vis/open OGLSX
/vis/viewer/zoom 2.0
/vis/viewer/set/viewpointThetaPhi   40  40
/vis/viewer/set/style surface
/vis/drawVolume
#/tracking/storeTrajectory 1
#/vis/scene/endOfEventAction accumulate

#setting the material database
/gate/geometry/setMaterialDatabase    GateMaterials.db


###### GEOMETRY ###########


#World generation
/gate/world/geometry/setXLength 150. cm
/gate/world/geometry/setYLength 150. cm
/gate/world/geometry/setZLength 150. cm
/gate/geometry/rebuild

# defining the cylindrical shape of the detector

/gate/world/daughters/name cylindricalPET
/gate/world/daughters/insert cylinder
/gate/cylindricalPET/geometry/setRmin 40. cm
/gate/cylindricalPET/geometry/setRmax 60. cm
/gate/cylindricalPET/geometry/setHeight 25. cm
/gate/cylindricalPET/geometry/setPhiStart 0 deg
/gate/cylindricalPET/geometry/setDeltaPhi 360 deg

/gate/cylindricalPET/setMaterial Water
/gate/cylindricalPET/vis/setColor blue
/gate/cylindricalPET/vis/forceWireframe


# defining the probe

/gate/world/daughters/name probe
/gate/world/daughters/insert sphere

/gate/probe/geometry/setRmin 0. cm
/gate/probe/geometry/setRmax 6. cm
/gate/probe/geometry/setPhiStart 0 deg
/gate/probe/geometry/setThetaStart 0 deg
/gate/probe/geometry/setDeltaPhi 360 deg
/gate/probe/geometry/setDeltaTheta 360 deg
/gate/probe/setMaterial Water
/gate/probe/vis/setColor red
/gate/geometry/rebuild


#making the detector blocks   HEAD- box of the detector    LEVEL 1 (rsector)

/gate/cylindricalPET/daughters/name head
/gate/cylindricalPET/daughters/insert box
/gate/head/placement/setTranslation 48. 0. 0. cm
/gate/head/geometry/setXLength 8. cm
/gate/head/geometry/setYLength 24. cm
/gate/head/geometry/setZLength 24. cm
/gate/head/setMaterial Air
/gate/head/vis/setColor green
#/gate/head/vis/setVisible                     1
/gate/head/vis/forceWireframe
/gate/geometry/rebuild




# borderline for the crystallboxdes- daughter of head     LEVEL 2  (module)

/gate/head/daughters/name block
/gate/head/daughters/insert box
/gate/block/placement/setTranslation 0. 0. 0. cm
/gate/block/geometry/setXLength 8. cm
/gate/block/geometry/setYLength 3. cm
/gate/block/geometry/setZLength 3. cm
/gate/block/setMaterial Air
/gate/block/vis/setColor red
/gate/block/vis/setVisible                     1
/gate/block/vis/forceWireframe

/gate/geometry/rebuild



# boxes for the crystals                                 LEVEL 3  (crystal)

/gate/block/daughters/name crystal
/gate/block/daughters/insert box
/gate/crystal/placement/setTranslation 0. 0. 0. cm
/gate/crystal/geometry/setXLength 8. cm
/gate/crystal/geometry/setYLength 3. cm
/gate/crystal/geometry/setZLength 3. cm
/gate/crystal/setMaterial Air
/gate/crystal/vis/setColor red
/gate/crystal/vis/setVisible                     1
/gate/crystal/vis/forceWireframe


#insert the crystalls                                   LEVEL 4    (layer0)

/gate/crystal/daughters/name LSOlayer
/gate/crystal/daughters/insert box
/gate/LSOlayer/placement/setTranslation 0. 0. 0. cm
/gate/LSOlayer/geometry/setXLength 8. cm
/gate/LSOlayer/geometry/setYLength 3. cm
/gate/LSOlayer/geometry/setZLength 3. cm
/gate/LSOlayer/setMaterial LSO
/gate/LSOlayer/vis/setColor yellow



# repeating the crystallboxes in a cubic array

/gate/block/repeaters/insert cubicArray
/gate/block/cubicArray/setRepeatNumberX 1
/gate/block/cubicArray/setRepeatNumberY 8
/gate/block/cubicArray/setRepeatNumberZ 8
/gate/block/cubicArray/setRepeatVector 0. 3. 3. cm



# repeating the detectors along one pet wing

/gate/head/repeaters/insert ring
/gate/head/ring/setRepeatNumber 2
/gate/head/ring/setAngularSpan 360 deg
/gate/geometry/rebuild



#repeating the wing in the oposite corner

#/gate/cylindricalPET/repeaters/insert ring
#/gate/cylindricalPET/ring/setRepeatNumber 2
#/gate/cylindricalPET/ring/setFirstAngle 220 deg

/gate/geometry/rebuild



# repeating the detectors along one pet wing

/gate/head/repeaters/insert ring
/gate/head/ring/setRepeatNumber 2
/gate/head/ring/setAngularSpan 360 deg
/gate/geometry/rebuild



#repeating the wing in the oposite corner

#/gate/cylindricalPET/repeaters/insert ring
#/gate/cylindricalPET/ring/setRepeatNumber 2
#/gate/cylindricalPET/ring/setFirstAngle 220 deg

/gate/geometry/rebuild



########### ATTACHING THE SYSTEM #####################

/gate/systems/cylindricalPET/rsector/attach   head
/gate/systems/cylindricalPET/module/attach    block
/gate/systems/cylindricalPET/crystal/attach   crystal
/gate/systems/cylindricalPET/layer0/attach    LSOlayer

# attaching the crystal
/gate/crystal/attachCrystalSD
# attaching the probe
/gate/probe/attach PhantomSD




###### SETTING UP THE PHYSICS############

##### physics: Photoeletric, Compton, ElectronIonisation, Positron 
annihilation, multiple scattering

/gate/physics/addProcess PhotoElectric
/gate/physics/processes/PhotoElectric/setModel PenelopeModel
/gate/physics/processes/PhotoElectric/setAugerElectron true

/gate/physics/addProcess Compton
/gate/physics/processes/Compton/setModel StandardModel


/gate/physics/addProcess ElectronIonisation
/gate/physics/processes/ElectronIonisation/setModel StandardModel e-
/gate/physics/processes/ElectronIonisation/setModel StandardModel e+


/gate/physics/addProcess PositronAnnihilation

/gate/physics/addProcess MultipleScattering e+
/gate/physics/addProcess MultipleScattering e-




### CUTS    to limit the maximum range of interactions that produce 
secondary particles #######
###         after the cut range no secondary particles are produced

/gate/physics/Gamma/SetCutInRegion      LSOlayer 2.0 cm
/gate/physics/Electron/SetCutInRegion   LSOlayer 2.0 cm
/gate/physics/Positron/SetCutInRegion   LSOlayer 2.0 cm


/gate/physics/Gamma/SetCutInRegion      probe 0.5 mm
/gate/physics/Electron/SetCutInRegion   probe 0.5 mm
/gate/physics/Positron/SetCutInRegion   probe 0.5 mm

/gate/physics/SetMaxStepSizeInRegion    probe 0.1 mm  # minimum stepsize 
between two physical events




#### INITIALISATION #######

/gate/run/initialize




###### ELECTRONIC RESPONSE OF THE DETECTORS (DIGITIZER) ###############


#### chain:  adder --> readout --> energy response --> spatial response 
--> threshold electronics --> dead time

### adder: regroups hits per volume to a pulse
### readout: regroups pulses per block
### energy response: reflects the response of the detector to the energy 
of the pulse
### spatial resolution: simulates the detector crosstalk
### thresholder & upholder: sets maximum and minimum energy values the 
detector will detect
### dead time:



# ADDER
/gate/digitizer/Singles/insert adder



# READOUT
/gate/digitizer/Singles/insert readout
/gate/digitizer/Singles/readout/setDepth 4    # depth means the 
hierarchy number in the geometry f.e. rsector depth 1 LSOlayer depth 4



# ENERGY RESPONSE
### contains: general energy blurring of the pulse, crystal blurring 
(because all detectors are made of the same crystal), 
transferefficiency, light yield, time resolution, noise


# general energy blurring of the pulse
/gate/digitizer/Singles/insert blurring
/gate/digitizer/Singles/blurring/setResolution 0.10
/gate/digitizer/Singles/blurring/setEnergyOfReference 511. keV


# local crystalblurring                                                # 
blurring the light that hits the detector
/gate/digitizer/Singles/insert crystalblurring
/gate/digitizer/Singles/crystalblurring/setCrystalResolutionMin 0.10   # 
for each crystalelement there is set a minimum and a maximum resolution 
(de/E) range
/gate/digitizer/Singles/crystalblurring/setCrystalResolutionMax 0.30
/gate/digitizer/Singles/crystalblurring/setCrystalQE 0.9               # 
QE = Quantum Efficiency,  probability for the event to be detected by 
the photo-detector
/gate/digitizer/Singles/crystalblurring/setCrystalEnergyOfReference 511. 
keV


# transfer efficiency                                                  # 
photoelecron loss within the detector
/gate/digitizer/Singles/insert transferEfficiency
/gate/digitizer/Singles/transferEfficiency/chooseNewVolume LSOlayer
/gate/digitizer/Singles/transferEfficiency/LSOlayer/setTECoef 0.28


# light yield                                                          # 
converts the pulse energy into the number of photoelectrons emitted
/gate/digitizer/Singles/insert lightYield
/gate/digitizer/Singles/lightYield/chooseNewVolume LSOlayer
/gate/digitizer/Singles/lightYield/LSOlayer/setLightOutput 27000       # 
27000 photoelectrons per 1 Mev


# time resolution                                                      # 
sets the time resolution of the detector
/gate/digitizer/Singles/insert timeResolution
/gate/digitizer/Singles/timeResolution/setTimeResolution 1.4 ns


# noise                                                  # noise signals 
caused by the radioactivity of LSO
/gate/distributions/name energy_distrib
/gate/distributions/insert Gaussian                      # defining the 
energy distribution of the noise - gaussian-
/gate/distributions/energy_distrib/setMean 450 keV
/gate/distributions/energy_distrib/setSigma 1 keV

/gate/distributions/name dt_distrib                      # defining the 
time distribution of the noise  -poisson-
/gate/distributions/insert Exponential                   # probability 
of detecting k events in a time interval of t is distributed
/gate/distributions/dt_distrib/setLambda 7.57 mus        # along a 
Poisson law P_1(k,t) = e^{-lambda t}*(lambda t)^k}/{k!}

/gate/digitizer/Singles/insert noise
/gate/digitizer/Singles/noise/setDeltaTDistribution dt_distrib      # 
using the distributions for the simulation of the noise
/gate/digitizer/Singles/noise/setEnergyDistribution energy_distrib



# SPATIAL RESOLUTION

### contains: crosstalk

/gate/digitizer/Singles/insert crosstalk                         # 
distributes 10% of input pulse energy to the adjacent crystals and 5% to 
the corner crystals
/gate/digitizer/Singles/crosstalk/chooseCrosstalkVolume block
/gate/digitizer/Singles/crosstalk/setEdgesFraction 0.1           # 
energy crosstalk through the edges
/gate/digitizer/Singles/crosstalk/setCornersFraction 0.05        # 
energy crosstalk through the corners



# THRESHOLDER & UPHOLDER

### contains: thresholder,

# thresholder                                                      # 
sets minimum and maximum energy values the detector responds to
/gate/digitizer/Singles/insert thresholder
/gate/digitizer/Singles/thresholder/setThreshold 250. keV
/gate/digitizer/Singles/insert upholder                            # 
setting a sigmoidal thresholder here would be possible too - s function 
that allows values
/gate/digitizer/Singles/upholder/setUphold 750. keV                # 
below the low threshold or higher than the high threshold

# limited transfer rate is neglected



# DEAD TIME OF THE DETECTOR

### contains pile up, dead time effect

#pile up = If N pulses enter in the time window of the same sensitive 
volume, the output pulse
#is defined by the sum of the energies and the pulse time is set to the 
last time of the last pulse participating to the pile-up
# leads to an effective loss of events --> paralysable dead time

# pile up
/gate/digitizer/Singles/insert pileup
/gate/digitizer/Singles/pileup/setDepth 4                      # 
hierarchy level 4 LSOlayer
/gate/digitizer/Singles/pileup/setPileup 100 ns


# dead time effect  -when the dector is processing one event he can't 
process another

/gate/digitizer/Singles/insert deadtime
/gate/digitizer/Singles/deadtime/setDeadTime 1 mus
/gate/digitizer/Singles/deadtime/setMode paralysable
/gate/digitizer/Singles/deadtime/chooseDTVolume LSOlayer
# access mode of the buffer is neglected


-----------------------------------------------------------------------------------------------------------

Now the question:


In the dead time sector there is an error concerning the following line:
/gate/digitizer/Singles/deadtime/chooseDTVolume LSOlayer

The failure message is: Nof higher level 5

Does anybody know what this means?    What can I do?

Thanks for your help!



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