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        List of changes in the program MCNelectron
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1.  that can be generated by the Fibonacci series  generator using a given seed  specified after the keyword    SEED        is still equal to 31329  Consequently   the random number streams with sequence numbers from 31330 to 2   31329   62658 will be generated  using the next seed  i e   the seed that exceeds the specified seed by 1   and the streams with sequence  numbers from 62659 to 65536 will be generated using the seed that exceeds the specified seed by 2  if  the seed value obtained by adding 1 or 2 is greater than 30081  then it is reduced by 30082      Added four CUDA specific keywords    use CUDA        skip CUDA        r CUDA    and    em CUDA      which allow to use lists of CUDA devices  as well as to assign device workload ratios for individual  CUDA devices  see the updated user manual for more details      Added a CUDA specific keyword    bankModeThr CUDA     which controls the    bank mode    when  option    heap CUDA 2    is used  The term    bank mode    refers to the choice of an electron that has to be  banked after an impact ionization event  the banked electron may be either the lower energy one  the so   called    secondary    or    knock on    electron   or the higher energy one  the    primary    electron   Normally   when option    heap CUDA 2    is used  the knock on electron is the one that is banked  However  this may  cause an overflow of the banked particles buffer in the case of high energies of source particles and thick  targets  Consequently 
2.  the bank mode is changed when the filling fraction of the banked particles buffer  exceeds a certain value  That    threshold    value of the filling fraction is specified after this keyword  Its  default value is 0 8  i e   the bank mode will be changed when the banked particles buffer is more than  80   full  In the case    heap CUDA 0    or    heap CUDA 1     this keyword is ignored  in those cases  the  primary electron is always the one that is banked      Added four command line keywords    NSTREAMS        SEED        N    and    E     The first three ones are  equivalent to corresponding keywords specified in the input file and allow overriding the number of  random number streams  the seed of the Fibonacci series random number generator and the number of  source particles specified in the input file  respectively  The keyword    E    makes it possible to replace the  definition of the source energy spectrum specified in the input file by a source of monoenergetic  particles     Added three command line keywords    in        out    and    alt    that must precede the names of the input file   the output file and the file with alternative cross sections information  respectively  previously  the file  names were entered without any keywords      Moved subfolders    W value    and    X rays    into a new subfolder    Simulations     Added a subfolder     Simulations Backscattering    with results of simulations of electron backscattering from a thick layer of  gold at i
3.  were updated correctly   This bug could have a  noticeable effect only when electron energy is comparable to the photon cutoff energy  1 eV by default   and when particle coordinates are tracked     1 1 0  2015 06 20      1  Plane crossing tallies have been added  together with corresponding keywords ETALLY and PTALLY  for electron and photon plane crossing tallies  respectively     2  Removed restrictions on the angle of incidence and on the position of the starting point of the incident  beam  it may be inside the layer      3  Added an option to use inner shell electron impact ionization cross sections calculated using the  distorted wave Born approximation  DWBA   The latter cross sections are the same ones that are used by  the PENELOPE code system  They are calculated using the code by D  Bote  F  Salvat  A  Jablonski  and  C  J  Powell  which was published in 2009  That code has been translated from FORTRAN into C using  f2c exe and incorporated into MCNelectron  it is contained in the file    IonCS cpp         4  Added CUDA support  together with 18 new keywords ending with     CUDA     15 of them may be used  both in the input file and on the command line  the remaining 3 keywords are command line only   As a  result  Nvidia graphics processing units  GPU  can now be used for simulations in parallel with the CPU   There are now two variants of MCNelectron  the CPU only one  executable file name MCNelectron exe   and the one with CUDA support  executable file name MC
4. 4 09 26   4  Fixed a bug that caused too small energies of Compton recoil electrons when tracking of secondary  photons was turned off     TRACK P 0         2014 09 27    5  Fixed a bug that caused the failure to start the file    W value MakeTable exe     if the runtime components  of Visual C   libraries  i e   the    Microsoft Visual C   Redistributable     are not installed on the  computer     1 0 9  2014 10 02      l     Simulation of several physical effects has been added      a  non isotropic angular distribution of bremsstrahlung photons     b  partial suppression of positron bremsstrahlung in comparison with electron bremsstrahlung    c  non isotropic angular distribution of photoelectrons     d  non uniform distribution of positron and electron energies during pair production     e  angular distribution of electrons and positrons created in pair production events         Doppler broadening of energy distribution of incoherently scattered photons     For each of those effects  there is a keyword in the input file  which allows    turning on    or    turning off     simulation of the effect  By default  all those effects are simulated  If any of those effects is    turned off      then it will be replaced by a simplified model  e g   isotropic bremsstrahlung  or neglected completely  as  in the previous version of MCNelectron  For some of those effects  there are other keywords controlling  some details of the simulation  see the updated README file for more informa
5. 5 07 15   17  The error messages displayed after detecting an invalid command line parameter have been made more  informative     2015 08 21    18  Fixed a bug in the CUDA version of MCNelectron that sometimes caused overflow of the banked  particles buffer when the option    heap CUDA 2    was used  Now that overflow is prevented by  controlling which of the two electrons existing after an impact ionization event is banked  when the  banked particles buffer is less than 80   full  the banked electron is the lower energy one  i e   the     secondary    or    knock on    electron   and if the banked particles buffer is more than 80   full  then the  banked electron is the higher energy one  i e   the    primary    electron   In the case    heap CUDA 0    or     heap CUDA 1     the banked electron is always the primary one  as before      1 1 1  2015 10 02      1  Added an option to use elastic scattering cross sections obtained from relativistic  Dirac  partial wave  calculations  Those cross sections were calculated using the code ELSEPA by F  Salvat  A  Jablonski and  C  J  Powell  which was published in 2005  These are the same cross sections that are used by the  PENELOPE 2014 code system  Their values are stored in files    Data ElasticDPW_totalCS dat    and     Data ElasticDPW_angularDistr dat    in binary format  The latter file contains angular distributions   which were calculated for electron energies from 10 eV to 1 GeV on a logarithmic scale  the increment  of the 
6. A devices with automatic workload balancing  this bug was caused  by rounding errors when converting a floating point number to an integer number      2015 11 12    7  Fixed a bug that caused exclusion of forced interactions from the sampled interaction types during analog  tracking of particles with weights below the cutoff value  This bug could affect the simulation results  only when at least one of parameters FORCING _WT_MIN or CUT_WT was not equal to zero  which is  the default value of those parameters      2015 12 02   8  Fixed a bug in MCNelectron CUDA that caused failure to terminate a CPU only simulation after the    minimum  maximum or average relative standard deviation of a    control tally    became less than the     target error        9  Fixed a bug in MCNelectron CUDA that caused incorrect value of the current minimum  maximum or  average relative standard deviation when checking for a termination condition in a two dimensional     control tally        10  Corrected the language in several error messages   2015 12 07     11  Fixed a bug that could cause a crash or incorrect results when the specification of the    target error    of a     control tally    was not the last entry of the line with the tally definition in the input file     10    
7. List of changes in the program MCNelectron    Below is the list of changes for each version of MCNelectron that was available for download from    http   web vu lt ff a poskus mcnelectron   up to the current version  1 1 2         1 0 1  2014 06 29      l     In the current version  electron positron pair production is simulated  However  a very simplistic model  is used  both the electron and the positron continue in the direction of the incident photon  and positron  energy distribution is assumed to be uniform     In the current version  positron annihilation is simulated  Each annihilation event occurs when positron  energy drops below the low energy cutoff value     In the current version  the source can emit positrons     PART E         Fixed a bug in the procedure that is used to determine if a particle has escaped from the layer    The current version implements a more realistic method of sampling of angular deflections of the two  electrons existing after an electroionizatoin event  Their deflection angles are calculated from  conservation of momentum    The search for energy values in cross section tables has been made faster  this has been achieved by    keeping in memory the current position in each table and using it as the starting position for the next  search   As a result  the total simulation time has decreased by 20       30       1 0 2  2014 07 01      l     In the current version  simulation of incoherent scattering at low energies  when atomic binding ef
8. Nelectron CUDA exe   The file  MCNelectron CUDA exe can perform GPU only  CPU only or hybrid CPU GPU computations  in  CPU only mode  MCNelectron CUDA exe produces the same results as MCNelectron exe      5  Changed the random number generator  The new random number generator is the original Fibonacci  series generator published by George Marsaglia and Arif Zaman in 1987  In addition  simulations using  CUDA devices may optionally use the XORWOW random number generator from the cuRAND library   the latter generator can not be used on the CPU   The CPU random number generator was changed  because the previous generator  which was a derivative of the one by G  Marsaglia and A  Zaman  was  less suited for generation of a large number   30 000  of independent random number streams     6  Added an option to apply a diffusion model of elastic scattering at extremely low electron energies  when  the elastic scattering cross section is much larger than cross sections of other types of interactions  When  the diffusion model is applied  the program first generates the distance to the next inelastic interaction  event  i e   the path traveled to that event  not the displacement   and samples the electron coordinates  corresponding to that event from a Gaussian distribution with a root mean square displacement  proportional to the square root of the generated path  This reduces the    electron trapping    effect  which  could otherwise slow the simulation significantly  at the expense o
9. base 10 logarithm of energy is equal to 0 1   Usage of those cross sections is controlled by the  switch    ELASTIC DPW     By default  that switch is    on     i e   those cross sections are used instead of  the ENDF    B elastic scattering cross sections     10     11     The default state of the switch    ION DWBA    is    on     i e   1  previously  its default state was    off     i e    0   Now  in order to avoid replacement of available ENDF B data by third party data  it is necessary to  specify the following three options in the input file     ION DWBA 0        ELASTIC DPW 0         BREMS POSITRON CORRECTION 0     the latter option has an effect only when pair production is  possible  or when the source emits positrons      Added an option to reduce the size of the tables with values of the angular CDF of elastic scattering by  removing some points from them  see the updated user manual for more details      Added an option to speed up the process of searching for values in tabular data by    mapping    the tables  to    index arrays    corresponding to sets of equidistant values  see the updated user manual for more  details      Added a range type    THETA     corresponding to the angle between the particle   s momentum vector and  the normal vector of a    tallying plane     see the updated user manual for more details      Increased the maximum number of random number streams from 31329 to 2      65536  However  the  maximum number of unique random number streams
10. d prevent  this from occurring anyway      2014 11 29    14  Fixed a bug that prevented periodic redistribution of random number streams among the threads to  equalize their workload  because of that bug  the mentioned redistribution was only done once per  simulation      15  Increased the maximum allowed number of random number streams from 256 to 2048     2014 11 30   16  Fixed a bug that sometimes caused incorrect value of the positron bremsstrahlung suppression factor            although inequality 0 02  lt             lt 1 was still always satisfied  as it should   This bug    rad  only showed up when there was non zero probability of pair production by photons and the target  material consisted of more than one chemical element  or when the source emitted positrons     2014 12 03    17  Fixed a bug that could cause an infinite loop in the part of the code that simulates photon Doppler energy  broadening during incoherent scattering  Such a situation occurred when the binding energy of the  selected atomic subshell happened to be greater than the incident photon energy  This bug has been fixed  by rejecting such subshells  i e   by selecting only subshells with binding energy less than the incident  photon energy     2015 05 15    18  Fixed a bug that prevented update of components of the electron momentum vector after a  bremsstrahlung event  when energy of the emitted photon was below the photon cutoff energy  the  absolute value of that vector and the electron energy
11. f fidelity of the simulated electron  trajectory when its energy is only a few electronvolts above the ionization threshold of the material  or  when it is below the ionization threshold  The transition to the diffusion model occurs at a user specified  value of the total to inelastic cross section ratio  The mentioned threshold value of that ratio is specified  by the keyword    DIFFUSION TOTAL TO INELASTIC RATIO THR     The allowed values of that  threshold are from 10 to 10    and the default value is 100  The diffusion model of elastic scattering is  never applied if the distance from the electron to the nearest surface of the layer is less than the mean free  path times the square root of this parameter  In order to    turn off    application of the diffusion model  this  parameter must be set to any sufficiently large value  e g   to the maximum possible value 1e18      7  The above mentioned Gaussian distribution is only exact when the electron is at a depth d large enough  to make the probability that the electron escapes from the layer before the next inelastic collision occurs  practically zero  Consequently  the diffusion model of elastic scattering may introduce significant errors  when estimating the moment and position of electron   s escape from the layer if the electron is close to  the surface  In order to decrease those errors  a single diffusion step mentioned above is replaced by a  sufficiently large number of shorter diffusion steps  which are less than 
12. fects  become important  is more realistic  The changes only affect the recoil electron  First  the atomic  subshell is randomly selected on the basis of the number of electrons in each subshell  The energy of the  ejected electron is obtained by subtracting the binding energy of the selected subshell from the energy  loss of the photon  If the resulting energy is negative  then the electron is not ejected from the atom   Otherwise  the direction of its motion is the same as in the case of a free electron  only the energy is  reduced as explained above   In previous versions  when tracking of particle position and direction was  turned on     TRACKPOS 1      the effect of binding on the recoil electron energy was ignored  only the  angular deflection included the effects of binding via the form factor      In the output file  a new row    backscatter    has been added under    photon loss    and    electron loss     It  contains the number and energy of particles that escaped from the layer through the surface that is  exposed to the incident beam  The number and energy of photons or electrons that escaped from the other  surface can be obtained by subtracting the values in the row    backscatter    from the corresponding values  in the row    escape        Fixed a bug that caused absence of angular deflection after coherent scattering of a photon     1 0 3  2014 07 04      1     2     The current version simulates Compton fluorescence  In the output file  the number and ener
13. gy of the  Compton fluorescence photons is shown separately from other fluorescence photons  However  the  number and energy of electrons emitted during atomic relaxation after an incoherent scattering event is  grouped with Auger electrons emitted after photoelectric absorption  similarly to MCNP6 output      Fixed a bug that caused incorrect number of pair production events in the output file     3     Added the keywords COH_THR  E_UNIT and E CONTIGUOUS to the input file  see the updated  README file for more information      1 0 4  2014 07 13      1     2     Added more information to the README file     Added a subfolder    Test    with six MCNelectron input files and six MCNP6 input files corresponding to  identical simulation conditions  together with respective output files  Additional information about those  files and instructions on running the tests are in the file    Test _ Test info  pdf        1 0 5  2014 07 19      l     3     Added the keyword NSTREAMS to the input file  It is used to specify the number of independent  streams of random numbers  For optimum performance  NSTREAMS should be a multiple of the  number of threads  see below   The maximum allowed number of streams is 256     Added multithreading capability  The number of threads is specified on the command line in the same  way as for MCNP  i e   as    tasks  lt number_of threads gt      If there is no keyword    tasks    on the command  line  then MCNelectron will run in single thread mode  On mult
14. i processor  or multi core  systems   multithreading can significantly reduce simulation time  The number of threads can be assigned any  value that does not exceed the number of streams of random numbers  see above   However  there is no  point in using a number of threads that is greater than the number of logical processors in the system  a  further increase of the number of threads will not cause a decrease of the simulation time   The final  results of the simulation do not depend on the number of threads that was used during the simulation     Updated the README file     2014 07 26     4     Updated the batch file    W value Make W tables bat     which is used to build the final tables of  W values  The previous version of that file worked correctly with MCNelectron v1 0 4 output files  but it  did not work with MCNelectron v1 0 5 output files  The updated version of    Make W tables bat    works  correctly both with v1 0 4 and with v1 0 5 output files     2014 08 13     5     Fixed a bug that could in extremely rare cases cause a crash after a positron annihilation event   probability of such a crash was less than 0 01        1 0 6  2014 08 23      l     Log log interpolation of photon cross sections and form factors has been made faster  This has been  achieved by calculating their natural logarithms before the simulation and then using those logarithms for  linear linear interpolation with natural logarithm of photon energy  or of the change of photon  momentum  as i
15. l and in the file    X rays _info_ pdf     which is in the same subfolder     2015 06 25    12  Fixed a bug that caused the seed of the XORWOW random number generator from the cuRAND library  to be always equal to the seed of the Fibonacci series random number generator  which is used on the  CPU    13  Fixed a bug that caused a CUDA error    invalid argument    after pressing any of the keys                           or     J    during simulation using options    emFirst_ CUDA 1    and    emLast_CUDA 1    on a computer with two  or more CUDA devices  i e   when the CUDA device No  1 was being emulated by the CPU  while the  CUDA device No  2 was not being emulated      2015 06 27    14  The inner shell electron impact ionization cross sections calculated using the DWBA approximation are  now stored in the file    Data lonDWBA dat    in binary format  instead of being recalculated at the start of  each simulation  Accordingly  the code for calculating those cross sections has been removed from  MCNelectron     15  Fixed a bug that caused incorrect values of inner shell positron impact ionization cross sections when the  option    ION_DWBA 1    was specified in the input file     2015 07 03    16  Added the file    randomlib c    with the original code of the Fibonacci series random number generator to  the distribution package  inserted a comment line with a reference to that file at the beginning of files     RandGen cpp        RandGen cu    and    RandGen_CUDA cu        201
16. ncident electron energies from 200 eV to 15 MeV  obtained with MCNelectron_CUDA using the  option    ELASTIC_DPW 1        12  MCNelectron and MCNelectron_CUDA are now distributed as WinRAR self extracting archives  The  names of those files are    MCNelectron_install exe    and    MCNelectron CUDA _install exe      respectively  They are contained in WinZip archives       MCNelectron_install zip    and     MCNelectron_CUDA install zip     respectively  they replace the files    MCNelectron zip    and     MCNelectron CUDA zip     which were used previously      13  Updated the user manual     2015 10 10    14  Fixed a bug that caused inconsistent sign of a bin count increment   1  when a range type    MU    was  used in the specification of a two dimensional plane crossing tally  before fixing this bug  the mentioned  sign depended on the direction of crossing  whereas for this range type the sign should be always  positive      15  Fixed a bug in the CUDA version of MCNelectron that caused inconsistent sign of a bin count increment    1  when a range type    THETA    was used in the specification of a two dimensional plane crossing  tally  before fixing this bug  the mentioned sign depended on the direction of crossing  whereas for this  range type the sign should be always positive   This bug affected only the 2D tallies calculated on CUDA  devices  but not the tallies calculated on the CPU      2015 10 14    16  Fixed incorrect interpretation of a negative value of the inpu
17. nput  As a result  the simulation time in problems where most of the time is spent for  sampling photon interactions  e g   a beam of photons incident on a thin layer  has become less than a  half of the simulation time with MCNelectron v1 0 5     When sampling the distance to collision  expression    1   pRand  gt random      has been replaced by     pRand  gt random       Although statistically the former expression is correct  too  because it also  corresponds to a uniform distribution   it involves one extra operation  subtraction   which is not  necessary  This replacement has been done in two places in the code  one for photons and one for  electrons   Because of this change  simulation results when some of the particles can escape from the  layer are not exactly identical to the results obtained with the previous versions  although they are  identical statistically     Added an optional command line keyword    output_cs     When that keyword is used on the command  line  files with values of excitation and electroionization cross sections are created before starting the    2    simulation  In such a case  MCNelectron creates a folder    Cross sections    in the current folder  with  subfolders for each of the chemical elements that are present in the target material  Each of those  subfolders contains a text file with values of the total excitation cross section  as well as text files with  electroionization cross sections for each subshell  Each of those files contain
18. s section is created  in addition to the files with ionization cross sections for individual subshells      If the ENDF data folder name  which is specified in the input file after the keyword DIR  does not  contain the full path  i e   if it does not start with the backslash         and does not contain the colon            then it is now assumed to be a subfolder of the folder where the MCNelectron executable is  rather than a  subfolder of the current folder   The same applies to the keyword    BREMS_ ANGULAR DISTR _ DIR      which is used to specify location of text files with bremsstrahlung angular distribution data  when the  mentioned binary file    Data Brems_angular_prob_dens dat    is not used     7  Updated the README file   2014 10 03   8  Multiple pulse height tallies are now allowed     9     If a value of absorbed energy exceeds the bin boundary of a pulse height tally by 10        of the bin  width or less  then that energy value is treated as though it is equal to that boundary  In a special case  when that boundary is the low energy limit of the tally energy range  the source particle is not counted     2014 10 05   10  Added the keyword INCOH_ IGNORE BINDING E to the input file  see the updated README file for    information about that keyword      11  Renamed the keyword    DOPPLER BROADENING    to    INCOH_DOPPLER         in order to be consistent  with the naming convention of the other keywords that control simulation of physical effects  the first  par
19. s two columns of numbers   energy values  eV  and corresponding cross section values  in barns      1 0 7  2014 08 26      1  Interpolation of cross sections has been made faster by calculating the slope coefficients for each energy  sub interval before the simulation and using their stored values for interpolation  in previous versions of  MCNelectron  the slope coefficients were recalculated during each step of the simulation   In addition   sampling of energy transfer during electroionization and bremsstrahlung  as well as sampling of angular  deflection during elastic scattering of electrons has been made faster using a similar approach  As a result  of those changes  the simulation time has decreased by 10  to 20  in comparison with  MCNelectron v1 0 6     2014 08 28    2  Fixed a bug that appeared after the most recent change  described in previous paragraph   That bug  caused incorrect simulation results when alternative cross sections were used  because then the  corresponding slope coefficients were not recalculated  instead  their values corresponding to the original  cross sections were used   After fixing that bug  the slope coefficients are recalculated using the updated  set of cross sections     3  Merged source files    thread cpp        thread h    and       MCNelectron h    with    MCNelectron cpp      Consequently  the total number of source files decreased from 6 to 3     1 0 8  2014 08 30      1  In the current version of MCNelectron  the values of cross 
20. sections  form factors and other quantities that  only depend on electron or photon energy are only recalculated when the particle energy changes  As a  result of this modification  the simulation time in problems where particle energy changes relatively  infrequently  i e  when most collisions are without energy change  or when the source emits  monoenergetic particles and the average number of energy loss collisions per source particle is much less  than 1  has decreased by 10   to 40   in comparison with MCNelectron v1 0 7  In    W value problems      i e   when both elastic scattering of electrons and coherent scattering of photons are switched off and the  target is infinite in all directions     TRACKPOS 0      the computational overhead associated with this  modification causes an increase of the simulation time by up to 10       2014 09 06    2  The runtime components of Visual C   libraries  i e   the    Microsoft Visual C   Redistributable     are  no longer required to be installed on a computer in order to run MCNelectron  before this fix  absence of  the mentioned files caused the error message    The program can   t start because MSVCR100 dll is  missing from your computer    after attempting to run MCNelectron      2014 09 12    3  Fixed a bug that caused an error message about incorrect format of the ENDF file when the target  material contained elements with atomic number greater than 86  i e   the elements that are after radon in  the periodic table      201
21. t of those keywords is derived from the name of an interaction type      2014 10 30    12  Added the capability to equalize the workload of different threads in multi threading mode  When a  thread finishes processing of all histories assigned to it  the program redistributes all unfinished random  number streams among the threads  so that the number of active threads stays the same  in the previous  versions  the threads were not restarted after termination   This is only possible when the number of  unfinished random number streams is not less than the number of threads  otherwise  each stream of  random numbers is assigned to a separate thread  so that the number of active threads is equal to the  number of unfinished random number streams      2014 11 14    13  Fixed a bug that could in extremely rare cases cause an indeterminate energy value      1  IND     of a  scattered photon when simulating Doppler energy broadening during incoherent scattering  Such an error  was possible when the sampled value of the projection of the electron initial momentum to the direction  of incident photon is very close to zero  resulting in calculation of the square root of a difference of two  very close numbers  Although the exact value of that difference is always non negative  the rounding  errors can make it negative  however  since there are no known cases of this actually happening  it is  possible that    granularity    of the random number generator implemented in MCNelectron woul
22. t parameter ELASTIC_PDF_ ERROR in the  CPU only version of MCNelectron  Before fixing this bug  a negative value of ELASTIC_PDF_ ERROR  was always interpreted by the CPU only version of MCNelectron as a zero value  i e   no values were  removed from tables with values of elastic scattering angular PDF   whereas the correct way is to ignore  the mentioned sign when the option    ELASTIC_DPW 1    is used  as explained in the user manual    Note  This bug was absent in the CUDA version of MCNelectron     1 1 2  2015 11 10    1  Added an option to use interaction forcing  see Section 4 5 in the updated user manual      2  The files with plane crossing and pulse height tally data now include relative standard deviations for  each bin  in addition to the particle counts      3  Added an option to terminate the simulation when the maximum  minimum or average relative standard  deviation  calculated over all bins of one or more plane crossing or pulse height tallies     control tallies       becomes less than the    target error    specified by the user  see Section 4 4 in the updated user manual      4  The simulations of electron induced characteristic X ray emission  folder    Simulations X rays    of the  distribution packages  have been re done using interaction forcing and    control tallies        5  Updated the user manual     2015 11 11    6  Fixed a bug in MCNelectron_CUDA that could cause    loss    of one source particle during a GPU only  simulation using two or more CUD
23. the root mean square  displacement and also less than d  but still greater than the mean free path   if d is less than a user   specified number of r m s  displacements  the latter r m s  displacement is estimated as described above    This number is specified by the keyword    DIFFUSION _DIST_TO_RMSPATH_ RATIO THR     The  allowed values of that number are from 2 to 10  and the default value is 5     8  After an electron impact ionization event  the banked electron is the higher energy     primary     one   rather than the    knock on    electron as in previous versions of MCNelectron   As a result  the number of  banked electrons has been reduced significantly in comparison with previous versions  usually by an  order of magnitude   An exception is a simulation on a CUDA device using the option    heap CUDA 2      in this case the banked electron is the lower energy one  i e   the knock on electron      9  Replaced the keyword    INCOH_IGNORE BINDING _E    by    INCOH_ SUBTRACT _ BINDING E        10  Updated the user manual     2015 06 24    11  Added the subfolder    X rays    with 99 MCNelectron CUDA input files and the corresponding output  files  Each of them is used to simulate characteristic X ray emission from a thick target composed of one  of those elements  C  Al  Si  Ti  Fe  Cu  Zn  Ge  Zr  Sn  Sm  Ta  W  Pt  Au and Pb  bombarded by  monoenergetic electrons with energy from 5 keV to 30 keV  Information about those files is provided in  Section 8 of the user manua
24. tion   Simulation of  bremsstrahlung angular distribution and Doppler broadening requires additional data files  which are  included in the MCNelectron distribution package  the file    Data Brems_angular_prob_dens dat    with  angular probability densities of bremsstrahlung  calculated by integrating analytically over the triply  differential cross sections derived by Bethe and Heitler  and the file    Data ComptonProfiles dat    with  Compton profiles  The data in the file    Brems_angular_prob_dens dat    is in binary format  it is described  in the updated README file   However  there is an executable    Data ExtractBremsAngularDistr exe      which extracts ASCII data from the binary data and creates a subfolder with human readable files  Those  text files can be used as input data for the simulation  too  instead of the mentioned binary file      The current version of MCNelectron can calculate a pulse height tally  similar to the MCNP    F8    tally      Added the keyword TRACK X to the input file  it controls tracking of X ray photons emitted due to  atomic relaxation      The energy of the Compton recoil electron is calculated simply as the difference of the incident and  scattered photon energies  1 e   the recoil electron energy is no longer reduced additionally by subtracting  the binding energy of the subshell from which the electron was ejected      When the keyword    output_cs    is specified on the command line  a file with values of the total ionization  cros
    
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