Do not show child pages within a file page

Your can use post_parent parameter for your query.
Ref: https://codex.wordpress.org/Class_Reference/WP_Query

This will change your query to:

$args = array(
    'post_type' => 'b_books',
    'order' => 'ASC',
    'orderby' => 'date',
    'posts_per_page' => 10,
    'post_parent' => 0
);

genesis_custom_loop( $args );