“À tous les temps, à tous les peuples”.

“À tous les temps, à tous les peuples”. Member and associated states of the Convention du mètre voted today in favor of the redefinition of the International System of Units (SI), in terms of exact universal constants. A millenary human quest, formulated more precisely 200 years ago during the French revolution. A philosophical dream which reaches beyond the “simple” redefinition of the kilogram.

The change will become effective on 20 May 2019, the anniversary date of the signature of the Convention du mètre in 1875 (and International Metrology Day).

I am going through the manual and trying to run the first EGSnrc as instructed there.

I am going through the manual and trying to run the first EGSnrc as instructed there. I am getting the following error:

EGS_Application::EGS_Application(int,char**):

the input file slab.egsinp does not exist or is not readable

The file is located at $EGS_HOME/myapp.

The input is given below:

################################

#

# Simple slab simulation

#

################################

################################

### RUN CONTROL

################################

:start run control:

ncase = 1e3 # The number of histories to simulate

:stop run control:

################################

### GEOMETRY

################################

:start geometry definition: # Only 1 geometry definition block allowed

### Define a plate of tantalum

:start geometry: # Many geometry blocks can be defined

name = slab # This name can be anything you like

library = egs_ndgeometry

type = EGS_XYZGeometry

x-planes = -5, 5 # in cm

y-planes = -5, 5 # in cm

z-planes = -10, 0, 0.1, 10 # in cm

:start media input:

media = vacuum tantalum # Indexed as 0 1

set medium = 1 1 # Set region 1 to medium 1 (tantalum)

# Other regions default to medium 0 (vacuum)

:stop media input:

:stop geometry:

### Use the geometry with this name for the simulation

simulation geometry = slab

:stop geometry definition:

################################

### MEDIA

################################

:start media definition: # Only 1 media definition block allowed

# Defining media in the input file like this is called “pegsless” mode

### Cutoff energies, in MeV

ae = 0.521 # lowest energy for electrons (kinetic+0.511)

ap = 0.01 # lowest energy for photons (kinetic)

ue = 50.511 # maximum energy for electrons (kinetic+0.511)

up = 50 # maximum energy for photons (kinetic)

### Tantalum

:start tantalum: # this name can be anything

density correction file = tantalum # name the file (no ext.)

:stop tantalum:

### Lead

:start lead:

density correction file = lead

:stop lead:

### Water

:start water:

density correction file = water_liquid

:stop water:

:stop media definition:

################################

### SOURCE

################################

:start source definition: # Only 1 source definition block allowed

### Pencil beam

:start source:

name = pencil_beam # This name can be anything you like

library = egs_parallel_beam

charge = -1

direction = 0 0 1

:start spectrum:

type = monoenergetic

energy = 20 # in MeV

:stop spectrum:

:start shape:

type = point

position = 0 0 -10 # in cm

:stop shape:

:stop source:

### Use the source by this name for the simulation

simulation source = pencil_beam

:stop source definition:

################################

### VIEWER CONTROL

################################

:start view control:

# Here we are just assigning some colors for nice

# viewing in the egs_view application

set color = lead 120 120 200 200

set color = tantalum 120 255 120 255

set color = water 0 220 255 200

:stop view control:

################################

### AUSGAB OBJECTS

################################

:start ausgab object definition: # Only 1 ausgab definition block allowed

### Particle tracks

:start ausgab object:

name = tracks

library = egs_track_scoring

:stop ausgab object:

:stop ausgab object definition:

hello everyone

hello everyone

I would like to know if anyone knows why in the results I get for the fluence of photons and electrons in several voxels, the average energy of the electron is greater than the average energy of the electron. This would not violate the law of conservation of energy?

Hello all

Hello all,

the slice numbers of my egsphant is flipped with respect to the original CT i.e. the first slice of egsphant is the last CT slice.

Is it possible for ctcreate to read dicom images in oder of decreasing Z? I’ll be grateful for other suggestions!

Thanks very much in advance

Isong

Hello fellow EGS users I could need some advice on best practice with parallel simulation of partial beam sources.

Hello fellow EGS users I could need some advice on best practice with parallel simulation of partial beam sources.

To test my cluster I have split the BEAM16MVp example into a phasespace file after the mirror and a partial simulation after.. I then start a parallel dosxyznrc run with that second partial beam simulation as source which runs fine on a single node. If however I start it in parallel the parellel runs never leave the beam simulation, massing up disk space until the computer is blocked. It works just fine with EGSchamber though… (might be because chamber uses EGS++ code)

I’m lost now. I bet this is something a lot of you do on a regular basis and I bet I am just missed some vital toggle or mortran preset. Any advice on what I might be missing would be welcome.

PS I tried both at and Torque, so I already think it isn’t a scheduler. based problem.

Hi all

Hi all,

I am trying to re-run an old simulation of a Co-60 source that was previously run on a 2004 version of BEAMnrc. The simulation is run in two parts: the first part produces a phsp file for the cobalt source and the second calculates dose in a medium from the phsp. The same input file with ECUT and AE for all media set to 521 keV gives me a minimum electron energy (from the .egslst file) of 0.000 MeV in the old version and 0.010 MeV in the current version. Is this a change in the way the results are reported between versions or is it a real difference? I am also seeing a 1.3% difference in the calculated doses using the new phsp file (with u<0.2%). Any help much appreciated.

Hi all

Hi all

I am working on dose verification using EPID, at this stage I need to calibrate the virtual linac. I calculated the dose at the isocenter at 10 cm depth using water block but I am not happy with the result so if you know how to do virtual linac calibration please contact me to discuss.

Your help is appreciated

Thanks

Hanan