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DAMPAK DERAAN KEKERINGAN P ADA FASE INISIASI BUNGA, FASE BERBUNGA DAN FASE PEMBENTUKAN POLONG T ERHADAP PEMBENTUKAN BUNGA DAN BUAH P ADA EMPAT VARIETAS VIGNA RADIATA Gaol, Mangadas Lumban; Ruma, Maria Longa; Sianturi, Hery Leo
Biota : Jurnal Ilmiah Ilmu-Ilmu Hayati Vol 14, No 1 (2009): February 2009
Publisher : Universitas Atma Jaya Yogyakarta

One of the greatest affected factors toward the growth of V. radiata is considered as the availability of water. Obviously, less production of V. radiata is due to short water supply. This research shows that flower initiation, flowering and fruiting to reproduction of four V. radiata varieties (Belu, Kenari, Perkutut and Murai), affected by drought are taken under this investigation. Based on numbers of initiated pod flowers and pods being produced, the most sensitive reproduction stages to drought in Belu variety were flower initiation and flowering, Kenari variety were flowering, Murai variety were flowering and fruiting, and Perkutut variety in all reproduction stages posses relatively similar level of sensitivity to drought. Generally, number of flowers initiated pods and the number of pods produced were higher in Kenari and Murai varieties compared to those on Perkutut and Belu. Based on numbers of flowers initiated pods and numbers of pods production, drought at flower initiation and flowering stage were more highly affected on Belu and Perkutut varieties compared to that of Kenari and Murai. Droughts on fruiting stage are highly affected on Perkutut varieties as well compared to other varieties. Therefore, based on plants production and their tolerance to drought, the best plants to be cultivated are Kenari and Murai.

Dampak Deraan Kekeringan p ada Fase Inisiasi Bunga, Fase Berbunga dan Fase Pembentukan Polong t erhadap Pembentukan Bunga dan Buah p ada Empat Varietas Vigna radiata Mangadas Lumban Gaol; Maria Longa Ruma; Hery Leo Sianturi
Biota : Jurnal Ilmiah Ilmu-Ilmu Hayati Vol 14, No 1 (2009): February 2009
Publisher : Universitas Atma Jaya Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24002/biota.v14i1.2634

One of the greatest affected factors toward the growth of V. radiata is considered as the availability of water. Obviously, less production of V. radiata is due to short water supply. This research shows that flower initiation, flowering and fruiting to reproduction of four V. radiata varieties (Belu, Kenari, Perkutut and Murai), affected by drought are taken under this investigation. Based on numbers of initiated pod flowers and pods being produced, the most sensitive reproduction stages to drought in Belu variety were flower initiation and flowering, Kenari variety were flowering, Murai variety were flowering and fruiting, and Perkutut variety in all reproduction stages posses relatively similar level of sensitivity to drought. Generally, number of flowers initiated pods and the number of pods produced were higher in Kenari and Murai varieties compared to those on Perkutut and Belu. Based on numbers of flowers initiated pods and numbers of pods production, drought at flower initiation and flowering stage were more highly affected on Belu and Perkutut varieties compared to that of Kenari and Murai. Droughts on fruiting stage are highly affected on Perkutut varieties as well compared to other varieties. Therefore, based on plants production and their tolerance to drought, the best plants to be cultivated are Kenari and Murai.

Interpretasi Bawah Permukaan Pulau Timor dengan Pemodelan 3D Berdasarkan Data Anomali Gravitasi Selciana Ginya; Jehunias L. Tanesib; H. L Sianturi
Magnetic: Research Journal of Physics and It’s Application Vol. 1 No. 1 (2021): Magnetic: Research Journal of Physics and It’s Application
Publisher : Program Studi Fisika - Universitas San Pedro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59632/magnetic.v1i1.75

Telah dilakukan interpretasi anomali medan gravitasi pulau Timor dengan pemodelan 3D untuk mengetahui batuan dasar pulau Timor. Data yang digunakan adalah anomali medan gravitasi udara bebas dan topografi Sandwell dan Smith yang telah direduksi terhadap model geopotensial bumi EGM2008. Koreksi data meliputi koreksi udara bebas, koreksi atmosfer, koreksi bouguer sederhana dan koreksi curvature. Data anomali bouguer lengkap dibawah ke atas bidang topografi dengan metode kontinuasi ke atas dengan ketinggian 25,9 km. Selanjutnya dilakukan pemodelan 3D dengan menggunakan program Grablox dan Bloxer. Hasil interpretasi kualitatif, diperoleh variasi anomali bouguer lengkap dari -160 mgal sampai 300 mgal. Nilai anomali positif lebih dari 0 mgal hingga sekitar 300 mgal. Anomali bernilai positif berada di hampir seluruh daratan pulau Timor dan sebagian di perairan laut Savu dan pulau-pulau di bagian utara pulau Timor serta di selatan perairan laut Timor yaitu setelah palung Timor, sedangkan anomali negatif kurang dari 0 mgal hingga sekitar -160 mgal berada di bagian selatan daratan Timor hingga perairan laut Timor dan sebagian besar laut Savu. Hasil interpretasi kuantitatif pada model 3D, tiap perlapisan didapatkan beberapa lapisan batuan di bawah permukaan yaitu batuan dolomit, granulit, sienit, dan batu sabak. Interpretasi data anomali gravitasi regional dan pemodelan 3D, diduga bahwa batuan dasar pulau Timor adalah batu sabak (slate) yaitu batuan metamorf yang terdapat pada kedalaman sekitar 3 km sampai 30 km.

Workshop Ilmu Fisika dan Aplikasinya untuk Guru Sekolah Dasar dan Menegah di Desa Oelnasi Kupang Tengah Albert Zicko Johannes; Jonshon Tarigan; Minsyahril Bukit; Zakarias S. Ngara; Hery L. Sianturi
Jurnal Nasional Pengabdian Masyarakat Vol. 1 No. 1 (2020): Jurnal Nasional Pengabdian Masyarakat
Publisher : Training & Research Institute - Jeramba Ilmu Sukses

In this paper, we demonstrate physical science training and its application for primary and secondary school teachers in Oelnasi Village, Kupang Regency, East Nusa Tenggara Province. Oelnasi Village is a new potential area in the development of science and technology (IPTEK) due to the availability of a national astronomical observation center in this area. The development of science and technology requires the development and improvement of knowledge related to natural phenomena. To realize this, we, Physics Lecturers at the Physics Study Program of the Faculty of Science and Technology, University of Nusa Cendana, carry out an activity to increase knowledge for elementary and junior high school teachers in Oelnasi village and around through physics training and its application. in community service activities. This activity is carried out in the form of a workshop session where the speaker provides the latest physics and development materials followed by a question and answer session. This activity can open insights and increase knowledge in the field of physics and its application for teachers.

ANALISIS SPEKTRAL DAN PENENTUAN HIPOSENTER GEMPA GUNUNG LEWOTOBI DAN EGON SERTA KONDISI SEISMOTEKTONIK DAERAH SEKITARNYA Stefanus Spulo Sogen; Hery L. Sianturi; Jehunias L. Tanesib; Devy K. Syahbana
Jurnal Fisika : Fisika Sains dan Aplikasinya Vol 2 No 1 (2017): Jurnal Fisika : Fisika Sains dan Aplikasinya
Publisher : Universitas Nusa Cendana

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (921.872 KB)

Abstrak Telah dilakukan penelitian tentang analisis spektral dan penentuan hiposenter gempa gunung Lewotobi dan gunung Egon serta hubungannya dengan gempabumi tektonik di daerah sekitarnya. Tujuan penelitian adalah menentukan karakteristik spektral, hiposenter gempa, b-value, serta menyelidiki hubungan antara gempa vulkanik dan gempa tektonik yang terjadi di daerah sekitar. Data kegempaan vulkanik diperoleh dari Pos PGA Lewotobi dan Pos PGA Egon dari tanggal 1 Januari sampai 31 januari 2016. Untuk data kegempaan tektonik diperoleh dari katalog international seismology center (ISC) dan U.S. Geological Survey National Earquake Information Center (USGS/NEIC) dari tahun 1965-2016. Analisis spektral dari gempa yang terekam di seismograf pos PGA digunakan untuk mendapatkan frekuensi dominan, untuk gempa vulkanik dalam, vulkanik dangkal dan tektonik lokal pada gunung Lewotobi digunakan untuk menentukan hiposenter gempa gunung Lewotobi. Untuk data gempabumi tektonik dilakukan analisis b-value. Hasil menunjukan bahwa frekuensi dominan setiap gempa yang terjadi pada gunung Lewotobi: gempa vulkanik dalam 10-13 Hz, vukanik dangkal 4,87-13,6 Hz, tornillo 1,69-16,8 hz, tremor harmonik 1,72-2 Hz, tektonik jauh1,041 – 5,282 Hz, tektonik lokal 1,80-2,79 Hz, hembusan 2,54-7,53 hz, low frekuensi 0,72-1,97 hz. Untuk gempa yang terjadi di gunung Egon: gempa vulkanik dalam 10-13,0 Hz, vulkanik dangkal 10-12,1 Hz, tremor harmonik 11-20,9 Hz, swarm 11-12,3 Hz, tektonik lokal 11,9-12,6 Hz, tektonik jauh 2,62-12,6 Hz, hembusan 4,88-12,8 Hz, low frekuensi 0,47-3,17 Hz, tornillo 12-12,6 Hz. Hiposenter gempa vulkanik banyak terjadi di gunung Lewotobi laki-laki dan tektonik lokal di baratdaya gunung Lewotobi. Nilai b-value yang diperoleh 1,12 ± 0,18. Dari hasil analisis tidak ditemukan korelasi langsung antara aktivitas vulkanik dan tektonik Katakunci: Lewotobi, Egon, Vulkanik, Tektonik, b-Value. Abstract Has done research on spectral analysis and determination of hypocenter Lewotobi and Egon and its relation to tectonic earthquakes in the surrounding area. The puporse of the research was to determine the spectral characteristics, hypocenter, b-value, as well as investigating the relationship between volcanic earthquake and tectonic earthquake that occurred in the area around. The data of volcanic seismicity obtained from the Lewotobi and Egon PGA Post on January 1st until January 31st 2016. And the data of tectonic seismicity obtained from International Seismicity Center (ISC) catalog and U.S. Geological Survey National Earthquake Information Center (USGS/NEIC) on 1965-2016. Spectral analysis of earthquake that recorded on a seismograph in PGA post used to get dominant frequency, the deep volcanic earthquake, shallow volcanic earthquake, and local tectonic on Lewotobi used to determine hypocenter of earthquake of Lewotobi mount. For the data of tectonic earthquake obtained by doing analysis b-value. The results show that dominant frequency each earthquake that occurred on Lewotobi: deep volcanic earthquake 10-13 Hz, shallow volcanic 4,87-13,6 Hz, tornillo 1,69-16,8 Hz, harmonic tremor 1,72-2 Hz, far tectonic 1,041-5,282 Hz, local tectonic 1,80-2,79 Hz, blowing 2,54-7,53 Hz, low frequency 0,72-1,97 Hz. For earthquake on Egon: deep volcanic earthquake 10-13,0 Hz, shallow volcanic 10-12,1 Hz,9 harmonic tremor 11-20,9 Hz, swarm 11-12,3 Hz, local tectonic 11,9-12,6 Hz, far tectonic 2,62-12,6 Hz, blowing 4,88-12,8 Hz, low frequency 0,47-3,17 Hz, tornillo 12-12,6 Hz. Volcanic hypocenter erthquakemostly occurred in Lewotobilaki-laki and local tectonic occurred on southwest of mount Lewotobi. The value of b-value obtained was 1,12 ± 0,18. From the result of analysis not founded a direct correlation of volcanic and tectonic activity. Keywords: Lewotobi, Egon, Volcanic, Tectonic, b-value

PEMETAAN MIKROZONASI SEISMIK DI DESA LILI KECAMATAN FATULEU KABUPATEN KUPANG Ida Nubatonis; Hery L. Sianturi; Bernandus Bernandus
Jurnal Fisika : Fisika Sains dan Aplikasinya Vol 2 No 2 (2017): Jurnal Fisika : Fisika Sains dan Aplikasinya
Publisher : Universitas Nusa Cendana

ABSTRAK Telah dilakukan penelitian tentang mikrozonasi seismik dengan metode HVSR di Desa Lili Kecamatan Fatuleu Kabupaten Kupang. Tujuan dari penelitian ini adalah mengetahui nilai frekuensi dominan tanah, amplifikasi, indeks kerentanan seismik dan percepatan tanah maksimum. Penelitian dilakukan dengan menggunakan TDS tipe 303 dengan frekuensi natural 0,2Hz-20Hz. Berdasarkan hasil penelitian, didapatkan bahwa nilai frekuensi dominan berkisar antara 0,279 Hz-17,210Hz, nilai amplifikasi berkisar antara 1,802-10,240 dan nilai indeks kerentanan seismik berkisar antara 0,422-421,167. Nilai percepatan tanah maksimum berkisar antara 160,769 gal – 279,316 gal dengan tingkat resiko besar dua dan tingkat resiko besar tiga. Kata kunci: Mikrozonasi, HVSR, Lili ABSTRACT The research about seismik microzonation using HVSR methods in Lili village, sub-district of Fatuleu, district of Kupang has been done. The aims of this research are to determine the values of soil dominant frequency, magnitude of amplification, seismik vulnerability index, and the peak ground acceleration. This research used TDS 303S type with0,2Hz-20Hz of natural frequency. According to this research, it was obtained that the values of the dominant frequency was about 0,279Hz-17,210Hz, the amplification values were found to be 1,802-10,240 and the index of vulnerability has values about 0,422-421,167. The peak ground acceleration values about 160,769 gal – 279,316 gal with great risk level two and great risk level three. Keywords: microzonation, HVSR, Lili

PEMETAAN MIKROZONASI SEISMIK DI DESA NUNKURUS KECAMATAN KUPANG TIMUR KABUPATEN KUPANG Roswita T. Saman; Hery L. Sianturi; Redi K. Pingak
Jurnal Fisika : Fisika Sains dan Aplikasinya Vol 2 No 2 (2017): Jurnal Fisika : Fisika Sains dan Aplikasinya
Publisher : Universitas Nusa Cendana

ABSTRAK Telah dilakukan penelitian mikrozonasi seismik di desa Nunkurus Kecamatan Kupang Timur Kabupaten Kupang. Penelitian ini bertujuan untuk mengetahui nilai frekuensi dominan tanah, nilai ampifikasi, indeks kerentanan tanah dan percepatan tanah serta membuat peta indeks kerentanan tanah dan peta. Berdasarkan hasil penelitian diperoleh nilai frekuensi dominan tanah berkisar antara 0.293 Hz – 18.41 Hz, nilai amplifikasi berkisar antara 1,68–8,52, nilai indeks kerentanan seismik berkisar antara 0,3285 –179,23556 dan nilai PGA berkisar antara 107,77488 gal-218,62941 gal sehingga dapat dikatakan bahwa daerah penelitian berada dalam kawasan yang cukup aman karena hanya sebagian titik saja yang memiliki nilai frekuensi, nilai amplifikasi, nilai indeks kerentanan dan nilai PGA yang besar. Kata kunci : Mikrozonasi, HVSR, Nunkurus ABSTRACT The research about seismic microzonation in Nunkurus village, sub-district of east Kupang, district of Kupang has been done. The aims of this research are to determine the values of soil dominant frequency, magnitude of amplification, seismic vulnerability index, the peak ground acceleration and to make seismic vulnerability index map and PGA map. The results showed that the values of the the values of the dominant frequency was about 0,293 Hz – 18,41 Hz, the amplification about 1,68 – 8,52. Meanwhile, the index of vulnerability was found to be 0,32853 – 179,23556 and peak ground acceleration values about 107,77488 gal - 218,62941 gal so it can be said that the area of research is safe enough because only a single point that has the frequency value, the value of amplification, the index value of vulnerability and PGA great value. Keywords : Microzonation, HVSR, Nunkurus

PEMETAAN NILAI PERCEPATAN TANAH MAKSIMUM DENGAN METODE DETERMINISTIC SEISMIC HAZARD ANALYSIS DI LOKASI PEMBANGUNAN OBSERVATORIUM NASIONAL DESA BITOBE KECAMATAN AMFOANG TENGAH KABUPATEN KUPANG Awanda Magdalena Bessi; Hery L. Sianturi; Bernandus Bernandus
Jurnal Fisika : Fisika Sains dan Aplikasinya Vol 3 No 1 (2018): Jurnal Fisika : Fisika Sains dan Aplikasinya
Publisher : Universitas Nusa Cendana

ABSTRAK Penelitian menggunakan metode HVSR (Horizontal to Vertical Spectral Ratio) telah dilakukan untuk memetakan daerah yang rawan terhadap gempa bumi di Desa Bitobe. Tujuan dari penelitian ini adalah mengetahui nilai periode dominan tanah dan percepatan tanah maksimum, serta untuk membuat peta PGA dan juga peta Mikrozonasi. Pengambilan data dilakukan pada 45 titik dengan jarak antar titik ± 250 m dari titik satu ke titik lainnya dengan waktu perekaman selama ± 20 menit menggunakan TDS tipe 303S. Data yang diperoleh diolah menggunakan software Datapro, Geopsy, Surfer 13, dan Google Earth. Hasil pengolahan data diperoleh nilai frekuensi dominan (). Parameter ini digunakan untuk meghitung nilai PGA menggunakan persamaan empiris Kanai dengan data katalog gempa bumi dari tahun 1966-2016. Metode Mc.Guirre dan Esteva hanya menggunakan data katalog gempa saja dalam menghitung PGA. Berdasarkan hasil penelitian, didapatkan bahwa nilai frekuensi dominan berkisar antara 0,273 Hz – 17,887 Hz. Nilai percepatan tanah maksimum berdasarkan persamaan empiris Kanai berkisar antara 32,319 gal – 261,178 gal, Mc.Guirre berkisar antara 128,215 gal – 134,862 gal dan Esteva berkisar antara 147,359 gal – 156,007 gal. Hasil dari ketiga persamaan ini memiliki perbedaan dengan peta hazard gempa Indonesia. Kata kunci: HVSR, Mikrozonasi, Kanai, Mc.Guirre, Esteva, Bitobe ABSTRACT The research using HVSR (Horizontal to Vertical Spectral Ratio) has been carried out to map the disturb areas to earthquakes in Bitobe village. The aims of this research are to determine the values of soil dominant frequency and the peak ground acceleration than make PGA map and also microzonation map. Data were collected at 45 points with the distance between points ± 250 meters from one point to the other with ± 20 minutes of recording time used TDS 303S type. The data were processed using software Datapro, Geopsy, Surfer 13, and Google Earth. The result of data processing was dominant frequency value (). This parameter was used to calculate the peak ground acceleration with Kanai empirical equations. The earthquakes catalog data were used from 1966-2016. Mc.Guirre and Esteva method only used the earthquakes catalog data to calculated the PGA. According to this research, it was obtained that the values of the dominant frequency was about 0,273 Hz – 17,887 Hz. The values of peak ground acceleration based on Kanai empirical equations about 32,319 gal – 261,178 gal, Mc.Guirre about 128,215 gal – 134,862 gal and Esteva about 147,359 gal – 156,007 gal. The result of this third equations have different with the earthquakes hazard map of Indonesia. Key Words: HVSR, Microzonation, Kanai, Mc.Guirre, Esteva, Bitobe

PENDUGAAN JENIS PERLAPISAN BATUAN DENGAN METODE GEOLISTRIK RESISTIVITAS PADA WILAYAH LONGSORAN DESA TOLNAKU KABUPATEN KUPANG Leonardus Nengga; Hery L. Sianturi; Redi K. Pingak
Jurnal Fisika : Fisika Sains dan Aplikasinya Vol 3 No 2 (2018): Jurnal Fisika : Fisika Sains dan Aplikasinya
Publisher : Universitas Nusa Cendana

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstrak Telah dilakukan penelitian tentang pendugaan jenis perlapisan batuan pada wilayah longsoran Desa Tolnaku, Kecamatan Fatuleu, Kabupaten Kupang. Penelitian ini bertujuan untuk mengidentifikasi jenis perlapisan batuan dan memperkirakan kedalaman setiap perlapisan batuan bawah permukaan di sekitar wilayah longsoran tersebut. Pengambilan data dilakukan menggunakan metode geolistrik resistivitas konfigurasi Schlumberger dan analisis data penelitian menggunakan software Res2Dinv untuk mendapatkan nilai resistivitas sebenarnya. Berdasarkan hasil penelitian, jenis batuan di lokasi penelitian terdiri atas batuan lempung (clay) dengan nilai resistivitas 1,1 – 27,60 pada kedalaman 5 – 105 m, batuan alluvium dengan nilai resistivitas 10,0 – 79,4 pada kedalaman 5 – 105 m, dan gamping (limestone) dengan nilai resistivitas 50,0 – 1.817 pada kedalaman 27 – 105 m. Kata Kunci: Geolistrik Resistivitas, Schlumberger, Res2Dinv Abstract A study on the estimation of underground rock petterns in Tolnaku village Kupang Regency has been conducted. The study aims to identify types of rock layers and to estimate the deph of each layer. Data was taken using geoelectricity method with Schlumberger configurasi while the data analysis was performed using Res2Dinv to obtain the real resistivity value. From the results, rocks foud in the research location are clay with resistivity being 1.1 – 27.6 (between 5 – 105 m), alluvium with resistivity being 10.0 – 79.4 (between 5 – 105 m), and limestone with resistivity being 50.0 - 1.817 (between 25–105 m). Key words: Geoelectric resistivity, Schlimberger, Res2Dinv.

DETERMINATION OF RADIOISOTOPE CONCENTRATION IN MINING SAMPLES WITH THE SIMPLE AND NEUTRON ACTIVATION ANALYSIS IN WEST TIMOR ISLAND EAST NUSA TENGGARA Bartholomeus Pasangka; Kirbani Sri Brotopuspito; Herry L. Sianturi
Jurnal Fisika : Fisika Sains dan Aplikasinya Vol 4 No 2 (2019): Jurnal Fisika : Fisika Sains dan Aplikasinya
Publisher : Universitas Nusa Cendana

Abstract [Determination of Radioisotope Concentration in Mining Samples with The Simple and Neutron Activation Analysis in West Timor Island East Nusa Tenggara] The nature of Timor island have contents of several kinds of mining mineral, which still buried in rock, one of them is radioisotope that deposit activity concentration in the rock is unknown. This radioisotope is needed in several sectors as an alternative energy sources that begin to be developed in Indonesia. Problems specifications were studied in this research about activity concentration of radioisotope in the sample of mining and investigate of its prospect. The methods of research comprise of observe/ survey, sampling, analysis, and interpretation, which are applied in two analysis modes: 1) the simple analysis, and 2) neutron activation analysis (relative method). The steps of sample processing consist of: 1) grouping, 2) drying, 3) refining I, 4) burning, 5) refining II, 6) balancing, 7) stabilizing, and 8) drying again. The last processing results the softes dust. Furthermore procedures with the simple analysis comprise of: 1) to count sample, 2) to correct with background, 3) to calculate concentration of radioisotope element within the mine sample. The procedures for neutron activation analysis: 1) the softest dust sample is put into the polyethilene capsule and irradiated together with standard sample, then refrigerated during one week, 2) to countfield and standard sample on the same time and detector is same calibrated, 3) to correct with background, 4) to calculate concentration of radioisotope element within the mine sample. The results of research: activity concentration of radioisotope deposit in mining samples at sub-district ofAmarasi Kupang Wast Timor Island with simple analysis about 4.36 x 10 µCi/ gram, result with neutron activation analysis about 43.8 part per million or 4.38 x 10-5 µCi/ gram up to 2.34 x 10 -4 unit up to 235.3 part per million or 2.353 x 10 -5 unit. Activity concentration of radioisotope deposit in mining samples give stimation that radioisotope deposit in mining samples is possible prospect for exploration but still necessary another data. Key words: determination; concentration; radioisotope; miningAbstrak Alam pulau Timor menyimpan berbagai jenis mineral tambang yang masih terpendam dalam batuan, salah satu di antaranya adalah radioisotop yang konsentrasi deposit dalam batuan belum diketahui. Rradioisotop tersebut diperlukan dalam beberapa bidang sebagai salah satu sumber energi alternatif yang sudah mulai dikembangkan di Indonesia. Spesifikasi masalah yang dikaji dalam penelitian ini menyangkut konsentrasi aktivitas radioisotop dalamsampel bahan galian dan menyelidiki keprospekannya. Metode penelitian meliputi observasi/survei, sampling, analisis, dan interpretasi, yang diterapkan dalam dua model analisis: 1) analisis sederhana, dan 2) analisis aktivasi neutron (motode nisbi). Langkah-langkah pengolahan sampel terdiri atas: 1) pengelompokan, 2) pengeringan, 3) penghalusan I, 4) pembakaran, 5) penghalusan II, 6) penimbangan, 7) penstabilan, dan 8) pengeringan. Pengolahan akhir menghasilkan debu sangat halus. Prosedur selanjutnya dengan analisis sederhana meliputi: 1) mencacah sampel, 2) mengoreksi dengan cacah latar, 3) menghitung konsentrasi radioisotop dalam sampel bahan galian. Prosedur untuk analisis aktivasi neutron: 1) sampel debu sangat halus dimasukkan ke dalam kapsul polyethilena dan diiradiasi bersamaan dengan sampel standar, kemudian didinginkan selama satu minggu, 2) mencacah sampel lapangan dan sampel standar padawaktu yang sama dengan detektor yang terkalibrasi sama, 3) mengoreksi dengan cacah latar, 4) menghitung konsentrasi radioisotop dalam sampel bahan galian. Hasil yang diperoleh: konsentrasi aktivitas deposit radioisotop dalam sampel bahan galian di Kecamatan Amarasi Kupang pulau Timor barat, berkisar antara 4,36 x 10 μCi/ gram sampai dengan 2,34 x 10 -5 satuan sampai dengan 235,3 ppm = 2,353 x 10 -4 μCi/ gram (analisis sederhana), dan 43,8 ppm = 4,38 x 10 -5 satuan (analisis aktivasi neutron). Konsentrasi aktivitas deposit radioisotop dalam sampel bahan galian memberikan gambaran bahwa deposit unsur dalam bahan galian tersebut kemungkinan prospek untuk eksplorasi (masih perlu data lain). Kata kunci: determinasi, konsentrasi, radioisotop, tambang

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