Patent Number: 055984495
Section: claims

1. A process for the synthesis of .sup.13 N-ammonia in a target system, in a synthesis apparatus comprising: circulating target water in said target system;  charging hydrogen into said synthesis apparatus to create a pressurized condition of 0.5 to 2 kg/cm.sup.2 to maintain the target water in a reducing atmosphere;  wherein said circulating is conducted continuously at a speed to prevent the target water in an irradiation cell from changing into an oxidizing atmosphere upon irradiation of a proton beam; and  irradiating said target water with a proton beam to produce .sup.13 N-ammonia having a radiochemical purity of 95% or more.  purifying target water containing .sup.13 N-ammonia by contacting said target water containing said .sup.13 N-ammonia with a Na-type cation-exchange resin to collect the .sup.13 N-ammonia, and  charging a saline solution to elute the .sup.13 N-ammonia collected. 2. The process for the synthesis of .sup.13 N-ammonia in a target system, in a synthesis apparatus according to claim 1 further comprising: 3. The process of claim 1 wherein the amount of target water used provides a hydrogen gas space which maintains the target water in a reducing atmosphere.