Card 6: Irradiation and cooling times
-------------------------------------

Refer to Section :ref:`4.3 <time-explanation-ex>` for an example utilizing these parameters.

.. _`param:itstep`:

.. rst-class:: no-caption-number

.. list-table:: **ITSTEP** :phits-other:`PHITS: other means`
   :header-rows: 0

   * - Value
     - Description
   * - (D=1)
     - Sum of the number of irradiation periods and cooling periods.

**Card 6a: Time and beam power listings**

Each of the following 3 entries must be listed on a single line, separated by any nonzero number of spaces, and this sequence must be repeated ``ITSTEP`` times on ``ITSTEP`` lines.

.. _`param:tbin`:

.. rst-class:: no-caption-number

.. list-table:: **TBIN** :phits-same:`PHITS: same name`
   :header-rows: 0

   * - Value
     - Description
   * -
     - Duration of an irradiation/cooling step. Note that these entries are not the time elapsed since the beginning of the first time step but rather the duration of each time step/bin :math:`\Delta t`.

.. _`param:tbinu`:

.. rst-class:: no-caption-number

.. list-table:: **TBINU** :phits-same:`PHITS: same name`
   :header-rows: 0

   * - Value
     - Description
   * -
     - Time units of ``TBIN`` expressed as a single character. Acceptable entries are seconds (s), minutes (m), hours (h), days (d), and years (y).

.. _`param:beampw`:

.. rst-class:: no-caption-number

.. list-table:: **BEAMPW** :phits-same:`PHITS: same name`
   :header-rows: 0

   * - Value
     - Description
   * -
     - Normalized beam intensity. The total beam intensity used by the code is calculated as ``BEAMPW`` :math:`\times` ``AMP``; likewise, the total neutron flux in each region is calculated as ``BEAMPW`` :math:`\times` ``FLUXS``. Thus, this allows for adjustment between full power (1.0), cooling (0.0), and beam powers above and below the nominal intensity. Setting ``BEAMPW``\ =0.0 is how the cooling time-steps are distinguished from the irradiation steps.

(Note: The end of the final time step listed here is used to terminate the calculation. Output cannot be requested at times beyond the sum of all ``ITSTEP`` time step values.)