Internment is the imprisonment or confinement of people, commonly in large groups, without trial. The term is especially used for the confinement "of enemy citizens in wartime or of terrorism suspects". Thus, while it can simply mean imprisonment, it tends to refer to preventive confinement, rather than confinement "after" having been convicted of some crime. Use of these terms is subject to debate and political sensitivities. 

Interned persons may be held in prisons or in facilities known as internment camps. In certain contexts, these may also be known either officially or pejoratively, as concentration camps. 

Internment also refers to a neutral country's practice of detaining belligerent armed forces and equipment on its territory during times of war under the Hague Convention of 1907. 

The Universal Declaration of Human Rights restricts the use of internment. Article 9 states that "No one shall be subjected to arbitrary arrest, detention or exile." 

The "American Heritage Dictionary" defines the term "concentration camp" as: "A camp where persons are confined, usually without hearings and typically under harsh conditions, often as a result of their membership in a group the government has identified as suspect." 

The United States set up concentration camps for Cherokee and other Native Americans in the 1830s. In 1864, the U.S. government forced 8,000 Navajos to walk more than 300 miles at gunpoint from their ancestral homelands in northeastern Arizona and northwestern New Mexico to an internment camp in Bosque Redondo, a desolate tract on the Pecos River in eastern New Mexico. From 1863 to 1868, the U.S. Military persecuted and imprisoned 9,500 Navajo and 500 Mescalero Apache. Living under armed guards, more than 3,500 Navajo and Mescalero Apache men, women, and children died from starvation and disease. Adolf Hitler admired the U.S. actions toward Native Americans, and in a 1928 speech he praised Americans for having "gunned down the millions of Redskins to a few hundred thousand, and now keep the modest remnant under observation in a cage."
Does it tend to be used to refer to preventitve confinemet raterh than confinement after having been convicted of some crime?
it tends to refer to preventive confinement, rather than confinement "after" having been convicted of some crime.