Indonesia is rich in diversity of agroindustrial products. Yet the tropical climate causes agroindustrial products being easily damaged. Techniques for food preservation have been widely known such as drying, cooling or freezing, canning, chemical use and others. To complement these techniques, a promising unconservative technique using ionizing radiation can be safely used to preserve food, without leaving residual radiation or hazardous chemical residues. Unfortunately in Indonesia, the irradiation technique was still not common since few industries have used this technique. Compared to the neighbouring countries, only Indonesia as a big country had no interest in developing irradiator technology. To introduce this technique to the public, especially investors, BATAN in 2017 built a pilot project named as Iradiator Gamma Merah Putih (IGMP). It was designed with maximum activity up to 2 MCi using Cobalt-60 as radioactive sources and can serve from low to high dose. By the time, the number of agroindustrial customers, as well as their quantity to be processed, are increasing. The irradiation technique becomes an appropriate technology for Indonesian agroindustries. It is then necessary to build gamma irradiation facilities in areas that have large agricultural yields. This way can minimalize crop losses and increase the quality of the agricultural products.

<p>Iradiator gamma, yang diberi nama iriradiator Merah Putih, telah selesai dibangun dan diisi dengan sumber Cobalt-60 dengan kapasitas sekitar 300 kCi. Dirancang untuk multiguna, iriadiator ini harus dapat menyediakan berbagai dosis serap dari rendah hingga tinggi. Sistem kontrol mengijinkan 4 opsi kombinasi rak-rak sumber dengan opsi aktivitas terkceil adalah 41,2 kCi. Di dalam bungker, produk akan menjalani mekanisme laluan iradiasi dengan tujuan agar mendapatkan dosis serap iradiasi yang beragam. Bungker menyediakan 72 posisi iradiasi. Di setiap posisi iradiasi, gerakan produk dapat dihentikan untuk jeda waktu tertentu menyesuaikan dosis serap iradiasi yang diinginkan. Waktu minimum bagi produk menyelesaikan menkanisme laluan iradiasi adalah 78,5 menit. Pengujian dosis dosimetri menunjukkan bahwa laju dosis serap opsi pengoperasiaan aktivitas sumber terkecil adalah 0,22 kGy per jam. Rasio Dmaks/Dmin bergantung pada densitas produk. Untuk densitas 0,2, 0,4, dan 0,6 g/cm3, rasio keseragaman dosis masing-masing adalah 1,54, 1,65, dan 1,71. Kombinasi karakterisasi mekanik dan dosimetri mengantarkan pada dosis serap minimum yang mungkin diperoleh sebesar 0,29 kGy. Dengan batasan minimum ini, segala tujuan iradiasi yang membutuhkan lebih besar dari dosis tersebut sangat dimungkinkan menggunakan iradiator Merah Putih seperti untuk karantina buah segar, pengawetan biji-biji serelia, buah-buahan kering, dan lain-lain. Permasalahan kapasitas produk juga menjadi bahan pertimbangan. Kapasitas produksi iradiasi bergantung berbagai parameter seperti dosis serap iradiasi yang diinginkan dan densitas produk, serta parameter operasional lainnya. Jika dibutuhkan dosis serap iradiasi Gy dan densitas produk 0,4 gr/cm3, maka kapasitas produksinya adalah 3,17 ton/jam atau 76 ton/hari. Kapasitas dapat berubah bila parameter iradiator juga berubah.</p><p> </p><p><strong>Characterisation and Potential use of Irradiator Red and White for Handling Food Product Agricultural.</strong></p><p>A gamma irrdiator called Irradiator Merah Putih, has been contructed and loaded with Cobalt-60 sources having a total activity of about 300 kCi. Designed for multipurposes, the irriditor should be able to provide low-to-high absorbed doses. The control system allows 4 options for combination of source racks with the smallest activity option is 41.2 kCi. Inside the irridiator bunker, the product to be irradiated will undergo an irridiation source pass mechanism in order to obetain uniform irradition absorbed dose. The bunker provides as many as 72 irradiation positions. At its position, the product maybe stopped for certain period of delight adjusting the desired irradition dose. The minimum time for the product to complete the source pass mechanism is 78.5 minutes. The dosimetry test showed that the absorbed dose rate for the smallest source activy operation was 0.22 kGy/hr. The Dmax/Dmin ratio depend on the product densitiy. For densities 0.2, 0.4, and 0.6 g/cm3, the dose uniformity ratios were respectively 1.54, 1.65, and 1.71. The combination of both mechanical and dosimetry characterization leads to a minimum absorbed dose of 0.29 kGy. With this minimum restriction, any irradiation objective requiring greater than that dose is posible using the irradiator Merah Putih such as for fresh fruit, quarantine, presservation of ceral grains, dried fruits,and others. The irradiator’s throughput is also considered. The irradiation capasity depends on various parameters such as the desired irradiation absorbed dose and the density of thr product as well as other operational paramters. If a 400 Gy of irradiation of absorbed dose is required for a product with the density of 0.4 g/cm3, its production capacity is about 3.17 ton/h or 76 ton/day. The capasity may change when irradiator operational parameters are also change.</p>

A preliminary prototype of a brachytherapy equipment has been constructed. The work started by developing conceptual design, followed by basic design and detailed design. In the conceptual design, design requirements are stated. In the basic design, technical specifications for main components are determined. In detailed design, general drawings are discussed. The prototype consists of three main systems: a mechanical system, an instrumentation system, and a safety system. The mechanical system assures the movement mechanism of the isotope source position beginning from the standby position until the applicators. It consists of three main modules: a position handling module, a container module, and a channel distribution module. The position handling module serves to move the isotope source position. As shielding, the second module is to store the source when the equipment is in standby position. The prototype provides 12 output channels. The channel selection is performed by the third module. The instrumentation system controls the movement of source position by handling motor operations. It consists of several modules. A microcontroller module serves as a control center whose task includes both controlling motors and communicating with computer. A motor module serves to handle motors. 10 sensors, including their signal conditionings, are introduced to read the environment conditions of the equipment. LEDs are used to display these conditions. In order to facilitate the operators' duty, communication via RS232 is provided. The brachytherapy equipment can therefore be operated by using computer. Interface software is developed using C# language. To complete both mechanical and instrumentation systems performance, a safety system is developed to make sure that the safety for operator and patients from receiving excessive radiation. An interlock system is introduced to guard against abnormal conditions. In the worst case, a manual intervention by the operator is provided when all other means are failing to store the isotope source into the safe container. The tests showed good results. The prototype can send the isotope source to applicators. The isotope source can be positioned with an accuracy of ± 0.5 mm and with a speed of 550 mm/second. These characteristics meet the design criteria.

UJI FUNGSI PROTOTIP PERANGKAT MEKANIK BRAKITERAPI MDR-lrI92-IB10. Telah dilakukan uji fungsi prototip sistem mekanik perangkat brakiterapi MDR-lr-I92-IB10, untuk mendapatkan data kesesuaian antara persyaratan disain dengan hasil prolotip yang telah dibuat. Perangkat ini merupakan prototip hasil rancang bangun PRPN-Batan yang bertujuan untuk terapi kanker. Serangkaian uji perangkat brakiterapi harus dilakukan untuk memperoleh data unjuk kerja. Perangkat brakiterapi merupakan integrasi dari sistem yang terdiri dari komponen sumber radiasi. Sistem mekanik dan software kontrol serta treatment planning system (TPS). Pada uji fungsi ini yang diamati adalah unjuk kerja integrasi sumber radiasi dengan sistem mekanik dengan tolok ukur ketepatan perintah software pada distribusi channel, kecepatan sumber diharapkan 35 mm/detik dan ketepatan posisi simpangan diharapkan maksimum 1 mm. Hasil pengujian menunjukkan bahwa ketepatan perpindahan distributor channel sesuai rancangan, kecepatan sumber hasil pengamatan antara 15 mm/dt sampai 20 mm/detik masih dibawah kecepatan yang diharapkan, sedangkan ketepatan posisi cukup baik kurang dari 1 mm.

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