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All Journal BERKALA FISIKA Sainstek : Jurnal Sains dan Teknologi
K. Sofjan Firdausi
Jurusan Fisika, Fakultas Sains dan Matematika, Universitas Diponegoro Semarang
Computer Science & IT Physics Other

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Journal : BERKALA FISIKA

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Penentuan Karakterisasi Cerrobend Sebagai “Wedge Filter” Pada Pesawat Teleterapi 60Co Azam, Much.; Firdausi, K. Sofjan; Silvani, Sisca
BERKALA FISIKA Vol 9, No 3 (2006): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Wedge filter usually used in cavum nasi ossa maxillaris tumor therapy. And usually it is made of timbal. However, cerrobend as the alternative material is possible and needed too. The material characterization is done through determining the linear absorption coeffisien of cerrobend and the proportion of the thickness of cerrobend to timbal,  and as well as comparing the total treatment dose rate of timbal wedge filter with cerrobend wedge filter. Based on the result of the research, it is found that the linear absorption coeffisien value of cerrobend wedge filter with energy of 1.33 MeV is 0.43% cm-1. The average ratio of the thickness of cerrobend to timbal is 1.485 ± 0.002, and the difference of the total treatment dose rate between those two wedge filter is only a little, that is 0.72 cGy/minutes.  Keywords : cerrobend, wedge filter and the linear absorption coeffisien
Pengukuran Panjang Koherensi Menggunakan Interferometer Michelson Setyaningsih, Agustina; Marhaendrajaya, Indras; Firdausi, K. Sofjan
BERKALA FISIKA Vol 10, No 4 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

A simple measurement of coherence length of He-Ne laser, red diode laser, and green diode laser using Michelson interferometer has been conducted. The steps in this research were setting up the Interferometer by places movable mirror on mirror rail. To determine the coherence length of the laser’s light, movable mirror has been shifted until the interference fringes disappear on the screen. Results of measurement for the coherence length of He-Ne laser I is  cm, He-Ne laser II is  cm, red diode laser I is cm, and green diode laser II is  cm. Keywords: Coherence, coherence length.
Penghitungan Rasio Intensitas Ca (II) 396,8 nm dan Ca (I) 422,6 nm pada Sampel Tasbih Asli dan Imitasi menggunakan Metode Laser Induced Shock wave plasma (LISPS) Khumaeni, Ali; Setia Budi, Wahyu; Firdausi, K. Sofjan
BERKALA FISIKA Vol 9, No 2 (2006): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Spectral analysis of elemental bead samples has been done using Laser Induced Schock Wave Plasma (LISPS). This experiment is aim to distinguish between bead samples from fresh white coral and its artificial from hardwood through determination of spectral intensity of Ca(II) 396,8 nm and Ca(I) 422,6 nm. The samples are held by 10 torr and induced by NdYAG Laser 1064 nm in wavelength. Results show that the original and artificial samples can be distinguished from ratio of intensity at 1,68 : 0,80 both for white coral and its artificial from hardwood through determination of spectral intensity of Ca (II) 396,8 nm dan Ca (I) 422,6 nm respectively.
Studi Efek Elektrooptis Pada Minyak Goreng Widyastuti, Nina; Azam, Much; Firdausi, K. Sofjan
BERKALA FISIKA Vol 12, No 2 (2009): Berkala Fisika
Publisher : BERKALA FISIKA

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The aim of this research is to study differences between fresh palm oil and heated palm oil in the external static electric field. The external electric field used at this research was resulted from two parallel plates of 5 × 3 cm, separated by 2.5 cm and applied by high voltage from 0 to 11 kV. Light sources used here were red laser pointer (= 650 nm) and green laser pointer (= 532 nm) to measure change of polarization angle. The heated oil used here was fresh oil that was heated in circa 16 minutes. The results indicate that fresh oil has less average gradient of electro optic polarization (h) than heated oil, both of 650 nm and 532 nm. Theh’s value is measured more significant for = 532 nm than= 650 nm, and moreover can be used to measure the quality of oils based on fresh or polluted oil.        Keywords: palm oil, electrooptic, polarization.
PEMBENTUKAN SIFAT OPTIS AKTIF MENGGUNAKAN MEDAN RADIO FREQUENCY (RF) PADA LARUTAN GARAM Kamil, Ahmad; Azam, M.; Firdausi, K. Sofjan
BERKALA FISIKA Vol 10, No 2 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The non-linear optical property of rotary power of light polarization in water and salt solution has been developed using the Radio-Frequency field (RF-Field). The RF-Field used in the experiment is produced by RF generator, and it supplies the frequency in the range between 6.04 to 14.56 MHz, which then applies to the samples. The source of light with 632.8 nm-wavelength and 532 nm-wave length are used to observe the change of angle polarization of the light, after it passes through the samples. Three modes of the direction of the electric field of light are chosen 0o (E//) (E of light is parallel to E of RF-Field, and 90o (E^) (E of light is perpendicular to E of the RF-Field) in order to determinate the optimal change of the angle of the polarization. The values of  is measured as a function of RF-Field, , where  is the angular frequency of RF-Field and BRF is the magnitude of magnetic field measured in the center of the coil which is assumed to be homogeny in the circumstances of the samples. The results of the experiment show that the degrees of change of the polarization direction, is largest at the  mode. It shows also that at small wavelength of light we obtain the larger, which is indicated the higher frequency of light will more induce the dipoles of molecules of the samples. Keywords: non-linear optics, polarization angle, rotary power
Pembuatan Hologram Refleksi Arifah, Arifah; Firdausi, K. Sofjan; Azam, M.
BERKALA FISIKA Vol 10, No 3 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

A Reflection hologram of a white ceramic object has been made on 5000 lines/mm PFG-03M holographic plate. A He-Ne Laser is used to record the holograms. And to reconstruct, it is used white, blue, and yellow light. The holographic plate for making of reflection hologram is PFG-03M. The optimal exposure time lies between 8 and 10 seconds. By reconstruction image white LED, it shows that the image is formed clearer than using blue and yellow light.   Keywords:  holography, reflection hologram, reconstruction, exposure time.  
Pengukuran Nilai  dan  Larutan Gliserin Terimbas pada Frekuensi PLN Firdausi, K. Sofjan; Lego, Dro Dwi; Sugito, Heri
BERKALA FISIKA Vol 10, No 4 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The magnetooptical specific rotary power h and frequence specific rotary power z have been measured in the glycerine through the interaction between external magnetic field modulated at 50-60 Hz and modulated laser light at the wavelength of 632,8 nm and 532 nm. The sample induced by the magnetic field that has the maximum value of 170 mT. The source of light of 632,8 nm and 532 nm is modulated between 30 Hz and 100 Hz. The result of experiment indicates that values of h and z at l = 632,8 nm are more dominant than at l = 532 nm.    Key words: magnetooptic, specific rotary power, resonance frequency
PENGARUH POLARITAS MEDAN LISTRIK EKSTERNAL DAN SUDUT POLARISASI LASER DIODA UNTUK PENGAMATAN EFEK KERR Wibowo, Hari; Sugiyanto, Eko; Firdausi, K. Sofjan; Marhaendrajaya, Indras
BERKALA FISIKA Vol 9, No 1 (2006): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

An identification of non linear optics of some material has been carried out. The samples used here are mineral water, salt solution, and sugar solution for various concentrations. A static applied external field E is adjusted to left and right direction. And also, the direction of electric field of laser is varied against E. The magnitude of E used in the experiment is produced by a DC high voltage (0-10 kV) applied on two identical parallel plates. A source of light to the samples is a diode laser of 645 nm and 5 mW. The change of polarization angle of laser b after through the samples is the optical property to be identified. Both of mineral water and salt solution, the effect of polarity of E shows identical results of b vs. E. In case of sugar solution, we obtain a positive gradient for right polarity and negative gradient for left polarity of E. Key words: non linear optics, polarization, polarization angle, Kerr Effect
Sifat Optis Tak-Linear Pada Material KDP Setyawan, Rahmadi; Setiawati, Evi; Marhaendrajaya, Indras; Firdausi, K. Sofjan
BERKALA FISIKA Vol 11, No 3 (2008): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Non-linier optical properties of transparent material Kalium Di- hydrogen Phosphate (KDP) have been identified under the influence of external magnetic fields at wavelength 632.8 nm and 532 nm by using Faraday Effect method. The external  magnetic fields used in this experiment is produced from coils with total turns of 810, wire diameter of 0,8 mm, and soft magnet core, and is flowed by maximum AC current 5 A. The magnitude of magnetic fields can be produced is 194.23 mT. The optical property measured here is rotation of polarization angle ß of the laser beam after passed the transparent material. From the experiment, it is obtained Verdet’s constant value for transparent material KDP is (12.60 ± 0.59) min/G-cm at  = 632.8 nm and (14.93 ± 0.73) min/G-cm at  = 532 nm.   Key words: non-linier optic, KDP, magnetic fields, polarization, Verdet’s constant
PENENTUAN KONSENTRASI AKTIVITAS URANIUM DARI INDUSTRI FOSFAT MENGGUNAKAN DETEKTOR ZnS(Ag) Setiani, Indri; Munir, Mohammad; Firdausi, K. Sofjan; Bunawas, Bunawas
BERKALA FISIKA Vol 9, No 2 (2006): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The activity concentration measurement of uranium (U238) in yellowcake sample which is coming from  phosphate fertilizer industry P.T. PETRO KIMIA Gresik  by using ZnS(Ag) detector has been done. In order to do this measurement, it is needed to callibrate and calculate the minimum detectable level of the detector. From the five samples that contain different yellowcake concentration, 400 mg of each samples were placed on five 2-inches-diameter stainless steel planchettes. HNO3 solution were added and the samples were shaken in order to make the samples as homogeneous as possible. The samples were totally evaporated under an infrared lamp until dry. Then they were counted by ZnS(Ag) detector. The uranium activity concentration measurement result of this method shows that sample with highest concentration of yellowcake (100%) have concentration activity 2,37 Bq/mg. While the sample with lowest concentration of yellowcake (37,5%) have concentration activity 0,95 Bq/mg. Key words     : uranium, phosphate fertilizer industry, ZnS(Ag) detector, yellowcake
Co-Authors Agustina Setyaningsih Ahmad Kamil Ali Khumaeni Anis Nila Kusuma Arif Fahmi ARIFAH ARIFAH Bunawas Bunawas Catur Edi Widodo Choirul Anam AM Diponegoro Dro Dwi Lego Dwi Satoto Edi Trijono B. S. Eko Sugiyanto Evi Setiawati Hadiyati Idrus Hapsari, Berliana Y. Hari Wibowo Heri Sugito Indras Marhaendrajaya Indri Setiani Istianah Istianah Jatmiko Endro Suseno Krisno Prabowo Lilik Eko Jatwiyono Moh. Yusron Mohammad Munir Much Azam Much. Azam Muchammad Azam, Muchammad Muhamad Adi Nanang Suriansyah Nina Khaerani Nina Widyastuti Prayitno Abadi Rahmadi Setyawan Rahmawati, Aidah Respita Sulistyo Risprapti Prasetyowati Setyoningrum, Aqilatul F.D. Sirojudin Sirojudin Sisca Silvani Soeleman Soeleman Soesanto, Qidir M.B Sulung Edy Nugroho Sumariyah Sumariyah Sutiah Sutiah Thithit Romadhona Tiwiyaningsih, Tiwiyaningsih Ummi Kaltsum Very Richardina Wahyu Adi Wibowo Wahyu Setia Budi Winarno Winarno