Over four decades, Fitchburg-bred photojournalist James Nachtwey has captured many poignant and powerful moments, amassing a haunting and historically significant body of work along the way. Now, Dartmouth College’s Hood Museum of Art has acquired that work — all of it. Nachtwey’s entire archive — a full 330,000 negatives, 170,000 digital images, 7,200 prints, and more, chronicling conflicts from the Rwandan Genocide to the global AIDS epidemic to the Sept. 11 attacks — will reside at the Hood Museum. “I hope that my archives will inspire future generations — in all fields, as well as future photographers — to approach the world with the same global perspective and concern for human dignity and social justice that I have sought to convey through my work,’’ Nachtwey, a Dartmouth alum, said in a statement. At 68, Nachtwey continues to work as a contract photographer for Time magazine, most recently covering the Syrian refugee crisis in Greece. The Hood’s impressive photography collection already includes works by Ansel Adams, Diane Arbus, Subhankar Banerjee, Hans Bellmer, Edward Burtynsky, Julia Margaret Cameron, María Magdalena Campos-Pons, Renée Cox, Rineke Dijkstra, Walker Evans, and Gordon Parks, among others.