[en] Semi Industrial Irradiation Plant (PISI) is a multipurpose facility which uses ⁶⁰Co sources to treat different products with numerous purposes, such as sterilization of medical devices, pharmaceutical and veterinarian products; control of pathogenic microorganisms, shelf-life extension and insect disinfestation of food, among others. In order to achieve the desired effect, the product is carried inside the irradiation chamber by means of a conveyor system, and it is exposed to radiation following a pre-established path. The recent installation of a new conveyor system at PISI demands the execution of a thorough validation programme. The scope of this presentation is to describe the dose mapping tasks that will be performed in order to characterize the irradiator and its new conveyor system with respect to distribution and variability of dose, complying with international standards on good irradiation practices. Information about the distribution and variability of dose in a product irradiated under defined conditions will allow the obtaining of process parameters which will conform the process specifications in future routine irradiations. The initial stages of the Validation Programme are the Installation Qualification, the Operational Qualification (OQ) and the Performance Qualification (PQ). To accomplish the IQ diverse tests are being carried out at PISI in order to verify that the system has been installed and is operating according to its technical specifications. Both OQ and PQ require dose mapping on simulated and real product, respectively. Dose mapping consists on placing dosimeters on a process load of homogeneous material -under certain irradiator and process parameters- according to a three-dimensional pre-established placement pattern. Since the replacement of the conveyor system introduces a significant modification in the source-to-product geometry, therefore in dose distribution, there is no reference dosimetry data available, so a more exhaustive dose-mapping will be required. Accordingly, the Operational Qualification will include dose mapping in air (i.e. without product), with the conveyor system both in a static position and moving along its path. Depending on the results obtained in the latter, dosimeter placement patterns will be defined for dose mapping on simulated product. The information acquired from the OQ will be the starting point for designing the PQ, in which the adequacy and reproducibility of the results shall be verified by means of dose mapping on real product and thus establishing the appropriate process parameters for ensuring conformity with dose requirements for these products.The aim of this special dosimetry is obtaining the process parameters such as dwell time, the product classification in different process categories, the magnitude and location of maximum and minimum dose points and their corresponding dose uniformity ratio. In conclusion, it must be remarked that this dosimetry will be more exhaustive than previous ones due to the unavailability of local referenced information for this system, and therefore, a more thorough dosimeter placing patterns will be required for the obtaining of these parameters in order to assure confidence on the future routine processing. (author)