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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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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
PENGARUH FAKTOR EKSPOSI PADA PEMERIKASAAN ABDOMEN TERHADAP KUALITAS RADIOGRAF DAN PAPARAN RADIASI MENGGUNAKAN COMPUTED RADIOGRAPHY Fahmi, Arif; Firdausi, K. Sofjan; Setia Budi, Wahyu
BERKALA FISIKA Vol 11, No 4 (2008): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

It has been researched about the change of exposure factors in radiographic examination of abdomen to radiographic quality and radiation exposure using computed radiography. The change of exposure factors to radiographic quality is obtained by measurement of radiographic density, which transmitted to step wedges and phantom abdomen. The density difference of step wedge and abdomen at each change of exposure factors result in radiographic contrast. To obtain radiation dose for patients, it is accounted by analytic method. The affect of scattering rate dose is obtained by measurement of scattering exposure rate using survey meter with positioned 100 cm from the object. The result of experiment shows that change of exposure factors in radiographic examination of abdomen makes no significant difference between radiographic density and contrast; however, it has decreased the patient dose. Keywords: radiation exposure, radiographic density and contrast
Penentuan Tebal Bahan Transparan (ZnO) Menggunakan Interferometer Michelson Edy Nugroho, Sulung; Firdausi, K. Sofjan; Marhaendrajaya, Indras
BERKALA FISIKA Vol 10, No 3 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Thickness’ determination of ZnO material on a substrate (microscope slide) by using Michelson Interferometer has been carried out. The material used in the research was ZnO transparent material deposited on a 1 mm-thickness of a microscope slide.  Refractive index of the microscope slide and the thickness of ZnO were measured by counting the fringes transitions as the materials rotated large as , on the other words, fringes transitions   as function of sinus incident angles  of laser ray, .  Incident angles of laser ray, which are used in the measurement of  ZnO transparent material thickness on microscope slide, are 1°, 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, and 10°.  Laser ray used in this research was He-Ne laser, which has 633 nm and its output power was < 1 mW. The results of this research show that there were  fringes transitions as research-materials rotated large as .  The measured fringes transitions still have remarkable agreement with the theoretical fringes transitions.  As the incident angles increases, the fringes transitions  will increase as well as.  The thickness of the ZnO thin film, which is resulted from the research, is equal to (6.0 ± 1.8) × 10-5 m.
KAJIAN AWAL SIFAT OPTIS TAKLINIER BAHAN TRANSPARAN DALAM MEDAN LISTRIK STATIS Prabowo, Krisno; Firdausi, K. Sofjan; Azam, Much.
BERKALA FISIKA Vol 9, No 1 (2006): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

In this paper, we study non linear optical characteristics of some transparency media in a static external electric field, E. The samples used in this experiment are mineral water, salt solution, and sugar solution. The optical characteristic investigated here is the change of polarization angle,b, of laser He-Ne after pass through the sample, against E. The strength of electric field is produced by high voltage (0-2000 volt) applied on two parallel plates (size 28 × 28 cm2). It is assumed that E inside the plates is homogeneous and fulfilled by relation of E = V/d. Results of experiment show that three samples have the tendency of b µ E in this experimental condition assumed to be optimal. For weak (mineral water) and strong (salt solution) electrolyte solution, we obtain a significant difference of gradient, that shows how dominant the electric dipoles in salt more than in mineral water. Other wise, change of b vs. E in sugar solution has only significant initial value of b. The tendency of b µ E is just only due to the contribution of dipoles of water molecules in sugar solution, since the sugar molecules is non polar.
Rancang Bangun Pengatur Cermin Sebagai Komponen Gerak Interferometer Pada Spektroskopi FTIR Adi Wibowo, Wahyu; Edi Widodo, Catur; Azam, M.; Firdausi, K. Sofjan
BERKALA FISIKA Vol 11, No 3 (2008): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

Michelson's interferometer and mirror regulator system as components of its power have been designed. Interferometers stirred component is one of monotonic mirror on optic system. Interferometer is made accords Michelson's Interferometer attempt. Mirror M1 and mirror M2 is assembled mutually upright then one beam splitter placed before both of mirror. One laser light source is given before mirror M1 crosses beam splitter. There is a detector before mirror M2 crosses beam   splitter upright with laser light source. Mirror M1 is made flexible by assembled gear and stepper's motor to be able forward or backward motion then so called moveable mirror.  Stepper's motor is turned around by computer via parallel port. From interferometer engineering and mirror regulator system already been made, gotten interference pattern with ring amount that the less each mirror gets forward motion and ring amount that more and more each mirror moves to backward. Shift moveable mirror every step for forward or backward is 1,5 µm with distance sails through maximal be 6,0 mm. The in common result point out that interferometer and regulator system of moveable mirror show feature changed interference pattern along with mirror move. Key word: interferometer, moveable mirror, motor stepper, parallel port.
Studi Interferometer Fabry-Perot Untuk Pengukuran Panjang Gelombang Cahaya Satoto, Dwi; Sugito, Heri; Firdausi, K. Sofjan
BERKALA FISIKA Vol 10, No 4 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

In this experiment, an interferometer Fabry-Perot method has been used to measure wavelength of diode laser. The first step is to calibrate the micrometer displacement using He-Ne laser in order to measure the diode and He-Ne wavelength. By shifting movable mirror, the transition of interference fringe in counted against the displacement of movable mirror. For the result of measurement, it is obtained for the wavelength of the red diode laser of, and green diode laser of.   Key word: Interferometer Fabry Perot, multiple beam interference.
Efek Magneto Optis pada Lapisan Tipis (ZnO) Adi, Muhamad; Firdausi, K. Sofjan; Setia Budi, Wahyu
BERKALA FISIKA Vol 10, No 1 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The magneto optics phenomenon on a thin film has been observed using Michelson Interferometer. The transparent materials used in the experiment is a cover glass (thickness of 1 mm) coated by the thin film ZnO (Zincite) in 54 mm of thickness. An external magnetic field which is applied to the transparent materials is in the order of 184,95 mT  obtained by a coil inserted by a soft magnet and given by the alternating current. To obtain the change of refractive index, an Michelson Interferometer has been used using He-Ne laser with = 632,8 nm and output power of 1 mW. The change of phase or refractive index of ZnO is very clearly shown by the increasing of number of fringes as the magnetic fields increases. The order of the linear coefficient magneto optics is 10-10 m/V indicates that it is very reactive to a external applied field. Keywords: Michelson Interferometer, Non-linear Optics, Refraction Index and Linear Magneto-optic Coefficients
Respon Non Linier Sifat Optis Larutan MgSO4 Firdausi, K. Sofjan; Azam, Much.; Romadhona, Thithit; Abadi, Prayitno
BERKALA FISIKA Vol 9, No 3 (2006): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

A response of nonlinear optic of several salt solutions in external magnetic field has been studied. An altered magnetic field varies from 0 until 0,2T used to induce samples, and then change of polarization angle b is measured by polarizators, where the direction propagation of laser is perpendicular to the direction of B. Various concentration of solution is used at 5% until 35%. Our experiment shows that the graphs of b vs. B are still linear for mineral water and NaCl solution. However, for MgSO4 solution, we obtained polynomial tendency of this graph. At 20% until 35% of concentration of this solution it has polynomial in third order. Keywords: Nonlinear optics, change of polarization angle, external magnetic field.
Efek Magnetooptis Pada Lapisan AgBr Terekspos Sulistyo, Respita; Firdausi, K. Sofjan; Marhaendrajaya, Indras
BERKALA FISIKA Vol 10, No 3 (2007): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The non linear optic characteristic from several transparent medium (film plate and glass) under influence of external magnetic field and variation of wavelengths, have been identified. In this experiment, the developed AgBr film is deposited on a hologram. The magnetic field has been produced by coils which connected to slide regulator (0-240V). The maximum value of magnetic field is about 182,0 mT. Light sources used are He-Ne Laser with a wavelength of 633 nm and 1 mW in power, and green laser pointer with a wavelength of 532 nm and power less than 5 mW. The optical characteristic measured in this experiment is the rotation of electric field, of the transmitted laser beam due to applied external magnetic field to the medium. The experiment result shows that  is dependent linearly on magnetic fields. The Verdet constant is proportional with wavelength of the light. Measured values for Verdet constant (V) at 632,8 nm is (0,487300,00070) min/G-cm and at 532 nm is (0,261700,00056) min/G-cm for glasses material and the values for Verdet constant at 632,8 nm is (0,328500,00060) min/G-cm  and at 532 nm is (0,156900,00039) min/G-cm for film plate.   Key words:Magnetooptical effect, non linear optic, Verdet constant
Studi Kualitas Minyak Goreng Dengan Parameter Viskositas Dan Indeks Bias Sutiah, Sutiah; Firdausi, K. Sofjan; Setia Budi, Wahyu
BERKALA FISIKA Vol 11, No 2 (2008): Berkala Fisika
Publisher : BERKALA FISIKA

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Abstract

The aim of this research to investigate the quality of palm oil through its viscosity and refractive index before and after used. Viscosimeter Ostwald is used to measure the viscosity and refractive method in prism is used to measure refractive index. The measurement was carried out in room temperature. The samples are fresh oil, and expired oil. Analysis of the quality of palm oil based on viscosity measurement and refractive index show that palm oil that had not been used is the highest value and the palm oil that twice used is the lowest value. Keyword: viscosity, quality of oil
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