Is there an operation for barretts syndrome besides halo?

Yes. Nissen fundoplication and esophagectomy are 2 other options but both are much more invasive than the endoscopic ablation technique that you mentioned.
Not really. Currently, there is no intervention that has been shown to prevent the development of barrett esophagus or its progression to esophageal cancer. Esophagectomy and endoscopic mucosal resection or ablation may be done in cases of high-grade dysplasia. A nissen fundoplication can reduce the reflux of acid from the stomach into the esophagus.