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"ABSTRACTGamma ray log is a logging tool to capture the radioactive level of a rock or formation measured in API units. This logging tool generally has a capability to differentiate between permeable and impermeable layers. Usually the impermeable layer tends to have higher radioactivity compared to the permeable one except for the feldspar bearing formation. In addition, another capability of this logging tool is ti determine the kind of clay mineral by using ratio data between Thorium and Potassium. This laboratory experiment uses Spectral Gamma Ray Equipment at LEMIGAS Routine Core Laboratory. The Quality of gamma ray log measurement is significantly affected by the speed of the conveyor belt. During the experiment, the measurement speed of 30 m/hour is the optimum speed to achieve good quality data and time efficiency with the data amount of 169 points/meter. The result of SGR measurement gives the reading on the content of Uranium, Thorium, and Potassium. The Thorium and Potassium content are compared and plotted in a Quirein graphic which was modified by Schlumberger in 1985. Using this crossplot, we can identify the presence of the Chlorite, Montmorillonite, Kaolinite, Illite, mixed with layer Feldspar, Mica, Glauconite minerals and so on. A case study conducted on Wells A1, A2, A3, and A4 indicated that the result of this crossplot was similar to the measurement using XRD."

"Widiastuti A, Sobir, Suhartanto MR. 2010. Diversity analysis of mangosteen (Garcinia mangostana L.) irradiated by gammaraybased on morphological and anatomical characteristics. Nusantara Bioscience 2: 23-33. The aim of this research was to increasegenetic variability of mangosteen (Garcinia mangostana L.) irradiated by gamma rays dosage of 0 Gy, 20 Gy, 25 Gy, 30 Gy,35 Gy and40 Gy. Plant materials used were seeds collected from Cegal Sub-village, Karacak Village, Leuwiliang Sub-district, Bogor District,West Java. Data was generated from morphological and anatomical characteristics. The result indicated that increasing of gamma raydosage had inhibited ability of seed to growth, which needed longer time and decreased seed viability. Morphologically, it alsodecreased plant heigh, stem diameter, leaf seizure, and amount of leaf. Anatomically, stomatal density had positive correlation with plant height by correlation was 90% and 74%. Gamma rays irradiation successfully increase morphological variability until 30%. Seedcreavage after irradiation increased variability and survival rate of mangosteen. "

"Iradiasi sinar gamma merupakan teknologi dekontaminasi ramah lingkungan yang dapat dijadikan alternatif yang efektif untuk mengurangi atau menghilangkan kontaminan pada simplisia. Pada penelitian ini dilakukan iradiasi sinar gamma dengan dosis 2,5; 5; 7,5 dan 10 kGy pada herba suruhan (Peperomia pellucida). Tujuan dari penelitian ini adalah mengetahui efek iradiasi terhadap aktivitas antioksidan, kadar fenol total dan flavonoid total pada sampel. Herba suruhan di ekstraksi menggunakan metode refluks dengan etanol 80% selama 30 menit. Ekstrak yang diperoleh di uji aktivitas antioksidan menggunakan metode DPPH, kemudian diukur kadar fenol total dengan pereaksi Folin Ciocalteu, dan diukur kadar flavonoid total dengan pereaksi AlCl3 menggunakan spektrofometer. Pada penilitian ini juga diuji korelasi terhadap nilai IC50 antioksidan dan kadar fenol total serta terhadap kadar flavonoid total. Hasil uji aktivitas antioksidan dan pengukuran kadar fenol total menunjukkan bahwa terjadi peningkatan yang signifikan pada sampel seiring dengan peningkatan dosis iradiasi. Kadar flavonoid total pada sampel yang diiradiasi mengalami penurunan yang signifikan bila dibandingkan dengan sampel yang tidak diiradiasi. Hasil uji korelasi menunjukan bahwa terdapat korelasi antara IC50 antioksidan dan kadar fenol total (r= -0,903; p<0,01) sedangkan uji korelasi antara IC50 antioksidan dan kadar flavonoid total memberikan hasil yang tidak signifikan (r= 0,687; p= 0,05).

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Gamma irradiation is an environmental friendly technology that can be used as an effective contaminants reducer in herbal products. The aims of this study were to evaluate the effect of irradiation on the antioxidant activity, total phenolic content, and total flavonoid content of Peperomia pellucida. In this study, the radiation processing of sample was carried out at dose 2.5, 5, 7.5 and 10 kGy. Samples were extracted by reflux method using 80% ethanol within 30 minutes. DPPH method was carried out to evaluate the antioxidant activity. Total phenolic content was estimated using Folin Ciocalteu's reagent and total flavonoid content by AlCl3. The result shows significant increased of antioxidant activity and the amount of phenolic by increasing the irradiation dose. There was a significantly decreased the flavonoid content after irradiation treatment. This study showed there were significant correlation between antioxidant activity with total phenolic content (r= -0,903; p<0,01) while antioxidant activity with total flavonoid content were not significantly correlated (r= 0,687; p=0,05)."

"Pengukuran dosis serap dalam bidang industri sterilisasi bahan pangan dengan menggunakan radiasi sinar gama merupakan salah satu faktor penting yang menentukan keberhasilan proses iradiasi. Dosimeter radiokromik merupakan salah satu dosimeter rutin yang dapat digunakan untuk memonitor proses iradiasi secara sederhana dan mampu memberikan informasi secara langsung yang berbasis pada perubahan warna yang dapat diamati secara visual setelah terpapar dosis radiasi pada tingkat tertentu. Penelitian ini melaporkan pembuatan dosimeter radiokromik dalam wujud cair dengan menggunakan zat pewarna alami yang berasal dari ekstrak bunga Hibiscus sabdariffa L. (rosela). Cairan radiokromik yang dipersiapkan sebanyak lima macam yaitu larutan ekstrak rosela dengan pelarut air destilasi ganda, larutan ekstrak rosela dengan pelarut etanol 70% dan larutan ekstrak rosela yang dicampurkan dengan larutan PVA dan larutan NaCl. Seluruh larutan yang telah dipersiapkan, diiradiasi gama menggunakan sumber radiasi Cobalt-60 dengan laju dosis 4,84 kGy/jam, dan di uji stabilitas dengan berbagai kondisi lingkungan. Karakterisasi sifat optik dilakukan dengan menggunakan spektrofotometer UV/Vis dan spektrofotometer FT-IR, selain itu perubahan warna larutan di dokumentasikan dengan kamera. Hasilnya menunjukkan larutan ekstrak rosela sensitif terhadap radiasi gama, dengan degradasi warna dari merah pekat menjadi merah tranparan setelah dipaparkan sinar gama dengan dosis 0-10 kGy untuk larutan ekstrak rosela dengan pelarut air destilasi ganda, sedangkan larutan ekstrak rosela dengan pelarut etanol 70% mengalami perubahan warna yang lebih tajam dari merah pekat menjadi kuning transparan dengan dosis 0-7 kGy. Larutan ekstrak rosela yang dicampurkan dengan larutan PVA dan larutan NaCl mengalami pola perubahan warna yang serupa dari dosis 0-1,5 kGy.

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Measurements of absorbed dose in the industry of food sterilization using gamma ray radiation are one of the important factors that determine the success of the irradiation process. Radiochromic dosimeters are one of the routine dosimeters to monitor the irradiation process by simply and able to provide information directly based on color changes that can be observed visually after radiation exposure at a certain dose level. This study reports the fabrication of liquid radiochromic dosimeters using natural dye from Hibiscus sabdariffa L. (roselle) flower extract. The liquid radiocromic has prepared as many as five types,  roselle extract solution with aquabidest as a solvent, roselle extract solution with 70% ethanol as a solvent and roselle extract solution mixed with PVA solution and NaCl solution. All the solutions has prepared, irradiated using gamma ray from a Cobalt-60 source with a dose rate of 4.84 kGy/h, and tested stability in various environmental conditions. Characterization of optical properties was carried out using a UV/Vis spectrophotometer and FT-IR spectrophotometer, in addition, the changes of the color of the solution documented using the camera. The results showed roselle extract solution was sensitive with gamma radiation, with color degradation from strong red to transparent red after being gamma ray irradiation at the dose 0-10 kGy for roselle extract solution with double distilled water, while roselle extract solution with ethanol 70% the degradation of the color more intense from red to faint yellow with doses of 0-7 kGy. The Roselle extract solution mixed with PVA solution and NaCl solution undergoes a similar degradation the color of the solution from a dose of 0-1.5 kGy."

"Salah satu komponen nutrisi utama pada beras adalah karbohidrat. Karbohidrat pada beras banyak tersimpan dalam bentuk pati. Pati dibagi menjadi dua fraksi, yakni amilosa dan amilopektin. Pati beras dapat dimodifikasi dengan berbagai cara untuk mendapat sifat baru yang lebih dikehendaki. Modifikasi pati beras dapat dilakukan dengan metode fisika salah satunya dengan sinar gama. Sinar gama merupakan isotop radioaktif berupa kobal-60 atau cesium-137 yang akan mengemisikan energi tinggi untuk menginduksi perubahan pada struktur pati dengan memfragmentasi ikatan glikosida pati. Pada penelitian ini sebanyak dua belas varietas beras organik dan nonorganik (Pandan Wangi, IR64, Rojolele, IR42, C4, dan Cisokan) dianalisis kandungan amilosanya setelah diberikan iradiasi sinar gama dengan variasi dosis 2, 5, 10, 20, dan 30 kGy. Pemberian iradiasi sinar gama menaikkan kadar amilosa pada varietas Pandan Wangi nonorganik, IR64 nonorganik, Rojolele nonorganik, IR42 nonorganik, C4 nonorganik, dan Cisokan nonorganik. Pemberian iradiasi sinar gama akan menurunkan kadar amilosa pada varietas Pandan Wangi organik, IR64 organik, Rojolele organik, IR42 organik, C4 organik, dan Cisokan organik. Berdasarkan uji lanjut Tukey ANAVA dua arah, dosis iradiasi sinar gama yang paling berpengaruh untuk mengubah kadar amilosa adalah dosis 10 kGy.

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One of the main nutrition component in rice is carbohydrate. Carbohydrate in rice is storaged well in the form of starch. Starch itself contains of two fraction, amylose and amylopectin. With certain method, rice's starch could be modified to obtain the desired property. Rice's starch modification could be done with gamma ray irradiation. Gamma ray is the radioactive isotope which could be obtained by the energy emitted by either cobalt-60 or cesium-137 that will induced the starch structural change by the manner of fragmentate the starch’s glycoside bond. The test used the rice from twelve rice variety from organic and non-organic rice (Pandan Wangi, IR64, Rojolele, IR42, C4, and Cisokan), the assay performed after the administration of 2, 5, 10, 20, and 30 kGy doses. The gamma ray irradiation dose that administered to those varieties downgraded the organic Pandan Wangi, IR64, Rojolele, IR42, C4, and Cisokan rice amylose content while upgraded the non-organic Pandan Wangi, IR64, Rojolele, IR42, C4, and Cisokan rice amylose content. According to the post-hoc test from two-way ANAVA, 10 kGy gamma-ray dose was the most affect to altered the amylose content."

"Penentuan karakteristik reservoar sekarang ini tidak hanya menggunakan pendekatan struktur, tetapi juga dapat diperoleh menggunakan teknik inversi, khususnya menggunakan metode model based. Pada teknik inversi ini dilakukan konversi data seismik menjadi impedansi akustik. Impedansi akustik inilah yang menjadi parameter penting dalam karakterisasi reservoar. Prinsip dasar inversi model based ini adalah bagaimana menentukan model bumi yang sesuai dengan data seismik riil. Untuk itu diperlukan korelasi antara synthetic trace dengan real seismic trace.Hasil korelasi yang diperoleh dari pengolahan data seismik dan data sumur ini sebesar 0,9147. Dengan hasil yang relatif sangat baik, bahkan mendekati ideal ini dapat ditentukan daerah reservoar yang mengandung hidrokarbon , tentunya dengan menggunakan beberapa parameter seperti : impedansi akustik, neutron porosity, gamma ray. Namun untuk menentukan daerah reservoar yang lebih baik diperlukan penelitian yang menggunakan metode lain dalam teknik inversi sebagai bentuk perbandingan.

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Nowadays how to delineate reservoir not only using structural method but also using inversion technique, particularly model based method. The process of inversion needs convertion of the seismic data to accoustic impedance. Accoustic impedance is prominent parameter when delineating reservoir. The basic principle of model based method is how to determine the appropriate model compared to seismic data which done iteratively . Therefore, it is necessary correlation between synthetic trace and real seismic trace. The final correlation between seismic data and well log which represented by real seismic trace and synthetic trace is 0.9147. Thus, it can be delineated reservoir area which have hydrocarbon , using some parameters such as: accoustic impedance, neutron porosity, gamma ray. However, it needs another application of inversion method as comparation in order to delineate the reservoir more accurate."

"Secara geografis, area Kuku Bima terletak di bagian ujung barat laut wilayah kerja PHE ONWJ, kira-kira 100 km ke arah barat laut Jakarta. Sedangkan secara geologi, area Kuku Bima terletak di suatu struktur tinggian yang memanjang dengan arah utara-selatan, dibatasi oleh cekungan Sunda di sebelah barat dan palung Seribu Utara di sebelah timur. Di sebelah utara dan selatan area ini terdapat 2 lapangan minyak, yaitu lapangan AA yang memproduksikan minyak dan gas dari formasi Talang Akar, serta lapangan ZU yang memproduksikan minyak dari formasi Baturaja. Pada area Kuku Bima sendiri terdapat 2 sumur eksplorasi, dengan penemuan kandungan minyak di batupasir formasi Talang Akar. Tes pada reservoar batupasir tersebut menunjukkan hasil yang cukup baik, berkisar antara 450-1300 BOPD. Hingga saat ini area Kuku Bima belum dikembangkan, karena temuan-temuan yang ada dianggap terlalu marjinal secara struktur. Pemahaman mengenai geometri dan penyebaran batupasir formasi Talang Akar di ONWJ masih sangat rendah. Beberapa penelitian terdahulu memperlihatkan bahwa pemetaan penyebaran batupasir ini tidak bisa dilakukan hanya berdasarkan pada amplitudo seismik. Hasil cross-plot antara Gamma Ray dan Impedansi Akustik (IA) menunjukkan bahwa IA tidak bisa digunakan untuk membedakan antara batupasir dan batulempung. Oleh karena itu, studi ini mencoba melakukan pendekatan yang lain melalui seismik multi atribut. Analisis seismik multi atribut dilakukan untuk mendapatkan volume pseudo-Gamma Ray dan volume pseudo-Density. Dengan membatasi nilai Gamma Ray dan Density pada kedua volume sesuai nilai cut-off batupasir di sumur dan mengintegrasikan kedua volume tersebut, penyebaran batupasir dapat dipetakan dengan amat baik. Berdasarkan hasil penelitian, penyebaran batupasir formasi Talang Akar dengan endapan yang lebih tebal ditemukan pada sayap sebelah timur tinggian. Sementara pada puncak-puncak tinggian, batupasir tersebut tidak banyak terendapkan. Dengan adanya penemuan ini, maka sayap sebelah timur tinggian dapat menjadi prospek baru untuk menemukan minyak dan gas di area Kuku Bima.

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Kuku Bima area is located in the northwest corner of PHE ONWJ operating block, nearly 100 km to the north west of Jakarta. Geologically, it is located on a north-south trending structural high, bounded by Sunda Basin to the west and North Seribu Trough to the east. The area is surrounded by two producing fields. AA field on the north is producing oil and gas from Talang Akar sands, and ZU field on the south is producing oil from Baturaja limestone. There were 2 exploration wells drilled in Kuku Bima area, resulting in oil discovery within Talang Akar sands.

Drill Stem Test (DST) on those reservoir shows good result, ranging from 450-1300 BOPD. Nowadays, Kuku Bima area is still left undevelop, considering that the discoveries are too marginal in term of structure. The understanding of Talang Akar sand geometry and its distribution is still considered poor.

Previous studies reveal the difficulty to image the sand distribution based on seismic amplitude. Cross-plot between Gamma Ray and Acoustic Impedance (AI) shows that AI alone cannot be used to distiguish sand and shale. In order to overcome this problem, this study offers a different approach by using multi attribute seismic. An analysis of multi attribute seismic is performed to generate pseudo-Gamma Ray and pseudo-Density volumes. Filtering Gamma Ray and Density values within those two volumes using cut-off values of sandstone in wells and integrating those two volumes afterward, will give a good result in mapping sand distribution.

Based on the study result, thicker Talang Akar sand deposition is distributed on the east flank of the structure high, while thinner Talang Akar sand are distributed on the crest. As the final result, the eastern flank of structural high will become a prospective area to discover oil and gas at Kuku Bima area."

"Hanafiah DS, Trikoesoemaningtyas, Yahya S, Wirnas D. 2010. Induced mutations by gamma ray irradiation to Argomulyo soybean (Glycine max) variety. Nusantara Bioscience 2: 121-125. Induced mutation by gamma ray irradiation is one way to increase genetic variability of plants. This research used gamma ray irradiation on low doses (micro mutation). The aim of this research was to know the respons of doses level by micro mutation on gamma ray irridation to the growing and development of Argomulyo variety of soybean [Glycine max (L) Merr]. The seeds were irradiated by gamma ray micro mutation doses, namely 0 gray, 50 gray, 100 gray, 150 gray, and 200 gray. Variations that were obtained of each characters at generation M1 and M2 influences plants growth and development either through qualitative and quantitative that finally will influence plant?s production. The average highest genetic variation at M2 generation of soybean was on 200 Gray doses. Results of the research indicated that gamma ray irradiation on 200 Gray doses effectively caused of plant variation genetic. "