Table of Contents ECSS Model Page
Background Information Geant4 tools
Geant4 material definition

Table of contents

  1. Overview
  2. Material definition
    1. User defined
    2. Predefined lists
  3. References


The material definition template allows the definition of either user defined or predefined (from an existing list) materials. These materials can in turn used by different Geant4 tools available in SPENVIS (Mulassis, GEMAT, Gras and Planetocosmics).

Material definition

The material definition page is split in two sections, namely User defined materials and Adding new material respectively . The first section consists of a table with the already defined user materials. When entering this page for the first time, a message "No user materials have been defined" is displayed. A user can delete any material from this list by clicking on the button next to the material name.

In the Adding new material section a user has four options for adding materials:

User defined material

The "User defined" option offers the possibility to define new materials by providing three input fields: a material name, chemical composition and density (in units of [g cm -3]). The name is chosen by the user, and should be unique. For the second field, the chemical composition, some special syntax is required: It consists of chemical symbol and stoichiometric proportion. A hyphen can be used to separate the different elements but will not be printed in the macro file. Isotope and stoichiometry are defined by integers only, i.e. you cannot use real numbers for stoichiometry. If the integer identifying the stoichiometric proportion is omitted, it will be assumed the value is unity. For example:

Predefined lists

When a user chooses a material from one of the three predefined lists (SPENVIS, NIST pure elements and compounds), the material name, chemical formula and density in [g cm -3] is also displayed. Note that these materials are predefined with respect to chemical composition and density.

In all cases, the new material can be added in the user defined material list by pressing the button.


  1. Geant4 Material Database
  2. NIST Material

Last update: Mon, 12 Mar 2018