Ionic Decrease Scroll Speed

i got problem when trying to slowing scroll from this code :

$ionicScrollDelegate.$getByHandle('credit').scrollBottom(true). 

How can i slowing down the scroll? Because now it scrolling too fast for me. I need to slowing down the scroll, just like credit scene on the Star Wars movie.

Anyhelp would be much appreciated, thanks!

------------- Edit

$scope.viewCreditsV2 = 
            function () {
                $ionicModal.fromTemplateUrl('views/popupcredit.html', {
                    scope: $scope,
                    animation: 'slide-in-up'
                }).then(function(modal) {
                        $scope.modal = modal;
                        $scope.modal.show();
                        if ($scope.modal.isShown()){                               
                            setTimeout(function() {
                                  // Do something after 2 seconds
                                 $ionicScrollDelegate.$getByHandle('credit').scrollBottom(true);
                            }, 2000);
                        }
                    });

                $scope.openModal = function() {
                    $scope.modal.show();
                };
                $scope.closeModal = function() {
                    // $scope.modal.hide();
                    $scope.modal.remove();
                };
            };