7.5. [ T-Deposit ] section

This tally can be used to obtain deposition energies (heat) in certain regions. After version 3.05, it tallies deposition energies not only by ionization of charged particles but also kerma of neutral particles. The necessity of the use of kerma approximation is automatically judged based on [parameters]: neutron kerma approximation is not used when e-mode>=1, while photon kerma approximation is not used when negs=1,2. Please see Section 5.2.8 for more details. Note that the neutron kerma approximation is available only for energies below dmax(2), where usually 20 MeV is set.

In the calculation of deposition energies by ionization of charged particles, any factor can be multiplied using the user-defined subroutines usrdfn1.f and usrdfn2.f. As examples, the default program of usrdfn1.f returns the dose equivalent calculated from the product of the deposit energy with the Q(L) relationship defined in the ICRP60, while that of usrdfn2.f estimates biological dose on the basis of the Microdosimetric Kinetic Model. Any factor can be changed and added using this routine. Note that letmat should be set to water when these default programs are used. See ParticleTherapy in the recommendation setting for more details. It should also be noted that this function cannot be applied to deposition energy calculation by kerma approximation and track structure mode.

The event generator mode as well as EGS mode should be used in the case of output=deposit, since deposition energies calculated by kerma approximation are not included in this option. In addition, this option cannot be used when weights of particles depositing energy change within a history, such as the cases where [weight window] or [importance] is defined.

Table 7.5.1 mesh

value

explanation

reg, r-z, xyz, tet

Mesh type. A mesh type subsection is required below this option.
Table 7.5.2 part

value

explanation

all (default), particle name

Tally particle. When output=deposit and deposit=0, all is necessary and only a maximum of 5 particles can be set. Deposition energies calculated by kerma approximation for neutrons and photons are scored in part=neutron and part=photon, respectively, as well as part=all.
Table 7.5.3 material

value

explanation

(optional)

Specify materials for scoring.

all

all is the default, same as no definition.

number of materials

To set number of materials, define the material numbers in the next line. The number of materials can be set as a negative value, in which case the specified materials are not included for scoring.

(next line)

2 5 8 Material numbers.
Table 7.5.4 letmat

value

explanation
(optional)
Material id for LET(\(dE/dx\)).
If not defined, a real material is assumed.
If a material not used in the geometry is selected, its material density must be defined in [material]. To calculate LET in water, define water with 1 \({\rm g/cm^3}\) in [material].
When letmat<0 is set, PHITS automatically calculates \(dE/dx\) for water with 1 \({\rm g/cm^3}\) for electrons and positrons: please see ParticleTherapy in the recommendation setting for more details.
Table 7.5.5 dedxfnc

value

explanation

(optional, D=0)

0: without. 1: use usrdfn1.f. 2: use usrdfn2.f. As examples, the default program of usrdfn1.f returns the dose equivalent calculated from deposit energy multiplied by the Q(L) relationship defined in the ICRP60, while that of usrdfn2.f estimates biological dose on the basis of Microdosimetric Kinetic Model.
Table 7.5.6 e-type

value

explanation

1, 2, 3, 4, 5

Energy mesh. See Section 6.6.1 for mesh subsection format.
Table 7.5.7 t-type

value

explanation

1, 2, 3, 4, 5 (optional)

Time mesh. See Section 6.6.1 for mesh subsection format.
Table 7.5.8 output

value

explanation

dose

Score the energy loss of charged particles and nuclei.

deposit

Score the variance of deposition energies by individual history. An e-type subsection is required.
Table 7.5.9 unit

value

explanation

0, 1, 2, 3, 4, 5

0: Dose [Gy/source], only for output=dose. 1: Dose [MeV/cm^3/source], only for output=dose. 2: Dose [MeV/source], only for output=dose. 3: Number [1/source], only for output=deposit. 4: Number [1/nsec/source], only for output=deposit. 5: Dose [J/m^3/source], only for output=dose.
Table 7.5.10 deposit

value

explanation

0 (default), 1

Option for deposit energy plot when output=deposit. 0: Distribution of total deposit energy with contribution of each particle. Please use this setting normally. 1: Distribution of deposit energy by each particle. This was the default setting until ver. 2.81.
Table 7.5.11 mother

value

explanation

(optional)

Specify mother nuclei for which kerma factors are calculated.

all

all is the default, the same as no definition.

number of mother nuclei

When setting the number of mother nuclei, define the mothers in the next line. The number of mother can be set as a negative value, in which case the specified mothers are not included for scoring. This parameter is effective only for dose calculations using the kerma approximation for neutrons and photons, because energy deposition from charged particles cannot be distinguished for each mother nucleus.
Table 7.5.12 axis

value

explanation

eng, reg, x, y, z, r, t

x axis value of output data.

tet

x axis value of output data, only active with mesh=tet.

xy, yz, xz, rz

2-dimensional.

t-eng, eng-t

2-dimensional energy-time representation.
Table 7.5.13 samepage

value

explanation

(optional, D=part)

The type of data to be displayed on the same page of the image output file. Parameters that can be defined in axis can be specified.
Table 7.5.14 file

value

explanation

file name

Define output file names. This is required by each setting of axis.
Table 7.5.15 resfile

value

explanation

(optional, D=file)

Define a file name of the past tally in the restart calculation. Even if several axis parameters were defined, specify only one resfile.
Table 7.5.16 factor

value

explanation

(optional, D=1.0)

Normalization factor.
Table 7.5.17 title

value

explanation

(optional)

Title.
Table 7.5.18 angel

value

explanation

(optional)

ANGEL parameters.
Table 7.5.19 sangel

value

explanation

(optional)

Special format for ANGEL parameters.
Table 7.5.20 2d-type

value

explanation

1, 2, 3, 4, 5, 6, 7

Options for 2-dimensional plot.

(optional, D=3)
Table 7.5.21 x-txt

value

explanation

(optional)

\(x\) axis title.
Table 7.5.22 y-txt

value

explanation

(optional)

\(y\) axis title.
Table 7.5.23 z-txt

value

explanation

(optional)

\(z\) axis title.

When unit=0 with output=dose, results can be obtained in units of [Gy/source]. When mesh=reg, the volumes of each cell should be defined in [volume] or set as volume parameters of [t-deposit]. Because absorbed dose is an intensive variable, PHITS does not output a sum over in output files for unit=0. Note that, in a region including more than two materials, the dose in the region does not equal the average value of the region. For example, when there are two materials with masses \(M_1\) and \(M_2\), and absorption energies \(E_1\) and \(E_2\), respectively, PHITS gives \(\frac{E_1}{M_1}\frac{V_1}{V_1+V_2}+\frac{E_2}{M_2}\frac{V_2}{V_1+V_2}\) in this tally, even though its average dose is \(\frac{E_1+E_2}{M_1+M_2}\). Here, \(V_1\) and \(V_2\) are volumes of the two materials.

By setting output=deposit, this tally can also be used for calculating the probability density of deposition energies by each history. This mode is useful for estimating detector responses and soft-error rates of semiconductor devices.

When output=deposit and deposit=0, the contribution of each type of particle set in part can be obtained from the result of all. In this case, if all is not set in part, part=all is automatically set.

By setting output=deposit and deposit=1, the distribution of energies deposited by each type of particle set in part can be obtained. Thus, the sum of results obtained by setting part= individual particle does not equal the distribution of energies deposited by all particles.

In the case of output=deposit and deposit=0, the statistical uncertainties of all results except for the values of part=all are calculated independently of istdev as standard deviations using history variance mode.

Table 7.5.24 gshow

value

explanation

0 (default), 1, 2, 3, 4, 5

When mesh=xyz and axis=xy,yz,xz, region border (1), material name (2), region name (3), and LAT number (4) are plotted using this option. gshow=5 outputs only material colors in pixel style when icntl=8.
Table 7.5.25 rshow

value

explanation

0 (default), 1, 2, 3

When mesh=reg,tet and axis=xy,yz,xz, region border (1), material name (2), and region name (3) are plotted using this option. A xyz mesh section must be added below this option.
Table 7.5.26 resol

value

explanation

1 (default)

This option multiplies the region line resolution by a factor of resol with the gshow or rshow option set to define the line thickness.
Table 7.5.27 width

value

explanation

0.5 (default)

The option defines the line thickness.
Table 7.5.28 volume

value

explanation

(optional)

This option defines the volume for each region for reg mesh. Volume definitions are required below this option. Values defined in [volume] are used in the case of no definition. If special description such as using (  ) is used to specify a region in reg=, its internally defined region number is output in input echo when this volume subsection is not defined.

reg vol

Volume definition. For details see the [volume] section.
Table 7.5.29 iechrl

value

explanation

72 (default)

Maximum number of columns for volume input echo.
Table 7.5.30 volmat

value

explanation

(optional, D=9)

This option corrects the volume value for each mesh when material is defined by the xyz mesh. 0 means no correction. Value of volmat is the number of scans per one xyz mesh side.
Table 7.5.31 epsout

value

explanation

0 (default), 1, 2

When epsout=1, results are plotted into eps files. The eps file is named by replacing the extension with .eps. When epsout=2, error bars are also displayed in the eps file, except for the 2-dimensional type, axis=xy, yz, xz, rz.
Table 7.5.32 bmpout

value

explanation

0 (default), 1

Generate Bitmap figure of 2-dimensional tally output. This file is named by replacing the extension with .bmp. When mesh=xyz and axis=xy, yz, xz, it is available.
Table 7.5.33 vtkout

value

explanation

0 (default), 1

Output the tally results in the xyz mesh in the input format of ParaView. This file is named by replacing the extension with .vtk. When mesh=xyz and axis=xy, yz, xz, it is available.
Table 7.5.34 vtkfmt

value

explanation

0 (default), 1

Format of output file for ParaView. 0: ascii, 1: binary.
Table 7.5.35 foamout

value

explanation

0 (default), 1, 2

When foamout=1, generate a file of outputs, numerical data, with OpenFOAM field data format. This file is named by replacing the extension with .foam. When foamout=2, generate a file of outputs, element number, center of mass x coordinate, y coordinate, z coordinate, volume, output data, relative error, with CSV format. This file is named by replacing the extension with .csv. When mesh=tet and axis=tet, it is available.
Table 7.5.36 ph5out

value

explanation

0 (default), 1

When set to 1, the tally results are output in the PHITS HDF5 file format (ph5). The file name is the same as the output file, with the extension changed to .ph5.
Table 7.5.37 maxangel

value

explanation

Number of part (default)

Specify the number of part shown in the eps file. This parameter limits the number of particles shown in a tally eps file, while it does not limit them in a numerical data file.
Table 7.5.38 ctmin(i)

value

explanation

(optional, D=-9999)

Minimum value for the i-th counter.
Table 7.5.39 ctmax(i)

value

explanation

(optional, D=9999)

Maximum value for the i-th counter.
Table 7.5.40 chmin(i)

value

explanation

(optional, D=-9999)

Minimum value for the i-th history-counter. This parameter cannot be specified in the batch variance mode, istdev=1.
Table 7.5.41 chmax(i)

value

explanation

(optional, D=9999)

Maximum value for the i-th history-counter. This parameter cannot be specified in the batch variance mode, istdev=1.
Table 7.5.42 trcl

value

explanation

(optional)

Coordinate transformation number or definition for r-z or xyz mesh.
Table 7.5.43 gslat

value

explanation

2 (default)

Option to draw lattice or tetrahedral geometry boundary lines when gshow or rshow is specified.

0

Not drawing.

1

Drawing. Note that the line of voxel phantoms may not be drawn clearly.

2

Not drawing the lines in the same cell.

3

Not drawing the lines in the same material. In this case, the boundary of two adjacent cells filled with the same material is not also drawn, even if not lattice or tetrahedral geometry. When gshow>=3, cell and lattice numbers are now shown.
Table 7.5.44 dresol

value

explanation

(optional, D=0.0)

Parameter for representing detector resolution. This is valid only for output=deposit. When dresol = \(\sigma_r\) and dfano = \(F\), the deposition energy \(E\) of each event fluctuates following a Gaussian distribution with standard deviation \(\sqrt{\sigma_r^2 + FE}\). If dresol<0, the energy resolutions, energy dependencies and spectral peak shapes, are overwritten by those defined in usrresol.f.
Table 7.5.45 dfano

value

explanation

(optional, D=0.0)

Parameter for representing detector resolution. Valid only for output=deposit. When dresol = \(\sigma_r\) and dfano = \(F\), the deposition energy \(E\) of each event fluctuates following a Gaussian distribution with standard deviation \(\sqrt{\sigma_r^2 + FE}\).
Table 7.5.46 stdcut

value

explanation

(optional, D=-1)

Threshold value of STD cut off.

When specifying stdcut, PHITS automatically stop the calculation depending on values of STD, standard deviation. This function is available when stdcut is positive and itall=0,1 is set in [parameters] section. When all relative values of STD of the tally result are larger than 0 and smaller than stdcut at the last of one batch, the calculation is stopped. If stdcut in two or more tally sections is set, all the results of the tally sections have to satisfy the conditions in order for the function to work.

Table 7.5.47 nlatcel

value

explanation

(optional)

By setting a cell number that has a LAT parameter, deposit energies in cells that have the same cell number but are placed in different lattice coordinates are processed as different cells. This works only for output=deposit.
Table 7.5.48 nlatmem

value

explanation

(optional, D=1000)

The maximum number of cells dealt with separately in one history.

Although the fano factor is generally defined as a dimensionless quantity, dfano is defined as a quantity with the dimension of energy. For example, dfano should be set to 3.62E-07 = 3.62E-06 * 0.1, when the fano factor is 0.1 and the average energy to create an electron-hole pair is 3.62 eV for a silicon detector.

As an extension of summing up deposit energies such as reg = (100 200 300 …), a weighted summation option is added. Using this option in this tally, energies deposited in specified i-th regions for each history, \(E_{\rm history,i}\), are multiplied by specified coefficients, \(\alpha_i(N_{\rm list})\), and then summed up as written by:

\[E_{\rm history} = \sum_i \alpha_i(N_{\rm list}) \times E_{\rm history,i}.\]

This option weights depending on deposited energies in each history, and it can be applied to simulation, for example soft errors in semiconductor devices. If you want to weight depending on the condition for each particle, please use user-defined subroutine, usrdfn1.f or usrdfn2.f, and set dedxfnc=1 or dedxfnc=2. This option can be used only with mesh=reg, and it can be executed when you specify reg convolution. Formats and examples are shown below.

Listing 7.5.1 Example of weighted summation option in [t-deposit].
mesh = reg
reg = weightsum
ncond = 4
no   cell   operator   ethres   list
1    100      ge         0.1      1
2    100      gt         0.2      1
3    100      eq         0.0      2
and  200      lt         0.4      2
4    100      le         0.5      3
ncell = 5
cell   list01   list02   list03   list00
100      0.0      0.5      1.0      1.0
200      0.1      0.6      2.0      1.0
300      0.2      0.7      3.0      1.0
400      0.3      0.8      4.0      1.0
500      0.4      0.9      5.0      1.0

First, define the number of conditions. The next line defines the order of data, condition number no, cell number cell, operator operator, threshold energy ethres, and list number list. In the next lines, conditions are described as many as the value of ncond. These lines mean that a list number is used when the energy deposited in the specified cell satisfies the greater or smaller relation with the threshold energy. The condition written first is preferred when the history satisfies some conditions. If the history does not satisfy all conditions, coefficients of list00 are used. You can set several conditions by writing and in the no column. In the cell column, you can use the format ( 2 -5 8 9 ) and the lattice and universe style ( 6 < 10[1 0 0] < u=3 ). However, you need to enclose a value by ( ) if it is not a single numeric value. In the operator column, you can use greater than gt, greater or equal ge, equal eq, less or equal le, and less than lt. The unit of ethres is MeV.

Next, define the number of convoluted cells. The next line defines the order of data, cell number cell, and list number listxxxx. In the next lines, convoluted cell numbers and coefficients are described. In the cell column, you can use the format ( 2 -5 8 9 ) and the lattice and universe style ( 6 < 10[1 0 0] < u=3 ). However, you need to enclose a value by ( ) if it is not a single numeric value. It should be noted that the same deposited energy is added many times when you set the same cell number many times. If you do not define list00, coefficients of list00 are set to zero.