あいだ
an interval of time, space, etc. connecting with verb: Unchanged, just add it directly.
先生がいない間に昼寝をする Taking a nap while the teacher is not here.
名詞・形容動詞: + だった・の
夜だった間に雨が降った ○ 夜の間に雨が降った ○ Rain fell in the time of evening.
かん
{五日間|いつかかん} During a period of 5 days
need to figure out what the difference is, and when which reading is used.