* Dealing with trauma after watching colleagues die
* Giffords undecided about whether to run again
By Tim Gaynor and Brad Poole
TUCSON, Ariz., Jan 5 (Reuters) - Congressional staffer Ron Barber was standing in a receiving line next to U.S. Representative Gabrielle Giffords at her first outreach event of the year when the gunman opened fire at point-blank range.
Moments later he was lying in a pool of his own blood on the sidewalk when Giffords and fellow aide Gabe Zimmerman fell beside him outside the Tucson area grocery store.
"I saw the congresswoman being shot, I saw myself being shot, I saw Gabe die in front of me," recalls Barber, 66, Giffords' district director who was shot in the face and thigh.
"They are memories that will never go away," added the aide, who has since been diagnosed with post traumatic stress disorder, or PTSD.
Sunday marks a year since a gunman fired a semi-automatic pistol into a crowd gathered at Giffords's "Congress on Your Corner" event last Jan. 8, killing six people and wounding 13 others.
As Tucson prepares to mark the somber anniversary, survivors like Barber are at various stages of recovery from the physical and emotional wounds of the deadly attack that ripped apart scores of lives, rocked this close-knit southwest city and shocked America.
"I've struggled with the emotions," said military veteran Bill Badger, 75, who was hailed as a hero for his role in ending the spree by grabbing accused triggerman Jared Loughner and slamming him to the ground before he could reload.
"It changed my life," he said.
Giffords plans to attend the candlelit vigil in Tucson on Sunday with her husband, retired astronaut Mark Kelly, although it remains unclear if she will seek to resume her political career and run for re-election in November.
Loughner was found mentally incompetent to stand trial at a hearing in May and is being treated at a federal prison hospital in Missouri.
COPING WITH TRAUMA
Hours after the shooting, Barber underwent emergency surgery at the University of Arizona Medical Center to repair damage from a bullet that struck his cheek and fractured his jaw, and from another that hit near his groin.
In the following months, as Giffords underwent intensive rehabilitation for a head wound at a hospital in Houston, Texas, Barber recovered sufficiently to return to work in July, where he was welcomed by colleagues with balloons and a carrot cake.
"I just love being here. They are wonderful people," Barber said in an interview at Giffords's Tucson district office, where he works half time.
"But being here was a daily reminder that Gabe wasn't here, because he and I would huddle six or seven times a day on issues," he said.
Zimmerman, 30 and a Tucson native, had worked for Giffords since her first congressional campaign in 2006. Colleagues remembered him as a gentle, thoughtful person.
A rising star among Democrats in the U.S. Congress, Giffords had been re-elected to a third term in the U.S. House of Representatives two months before she was shot.
After life-saving surgery for a "through-and-through" head wound - meaning the bullet went into and out of her head - she began months of intensive physical therapy at the TIRR Memorial Hermann hospital in Houston, where she has made strides recovering movement and speech.
Walking gingerly and blowing kisses, she made a triumphant return to the U.S. Congress for a vote on raising the U.S. debt ceiling in August, to thunderous applause.
Giffords said in a recorded message in November she wanted to "get back to work" but has not yet announced whether she will run for Arizona's District 8 again in November.
"She is not right now concerned about whether she's going to run for re-election," her spokesman Mark Kimble said, adding she was focusing on her recovery.
Giffords has until May to register to run for re-election, and has an organization in place that is continuing to raise funds for a campaign.
"She'll decide that when she decides it," Kimble said. "It'll be some time in the first part of 2012, but beyond that it's up to her." (Editing by Daniel Trotta and Cynthia Osterman) ((firstname.lastname@example.org; +1 480 518 0724)