array containing fields to display on multiple pages

I would like to have an array saving fields to display for an object
that is used for it's form on multiple pages.

I have declared the array in each of the controller methods that would
use it. for example,

  def new
    @echantillon = Echantillon.new

   @new_ech_columns = Array.new

  @new_ech_columns = [
          ["Brut","brut"],
         ["Disponibilite","availability"],
         ["numero d'inventaire de l'oeuvre","inv"],
         ["denomination","name"],
         ["numero du laboratoire","oeuvre_work_number"],
         ["type d'echantillon","echantillont

    etc....

and also in

  def edit

  @new_ech_columns = Array.new

  @new_ech_columns = [
         ["Brut","brut"],
         ["Disponibilite","availability"],
         ["numero d'inventaire de l'oeuvre","inv"],
         ["denomination","name"],
         ["numero du laboratoire","oeuvre_work_number"],
         ["type d'echantillon","echantillon

etc.....

and in other methods. Where can I put the array so that I only have
to define it once and then use it repeatedly on different pages?