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?