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"ABSTRACT

Probing of the atmospheric parameters have been done by many scientists since a century ago up to present with various techniques. A simple system of laser radar without using any collimated beam but a reflected mirror as transmitter and a small cassegranian type (10.5 an in diameter) telescope as receiving was constructed to investigate the relative Mie backscattering coefficient by utilizing a nitrogen laser as a light source in the range of measurement bellow 1 Km. The backscattered light received by the receiving telescope is converted into electric current by photomultiplier and is shown and known as "A scope" display on an oscilloscope. SNR of the signal from photomultiplier was increased by using a boxcar integrator and its output could be recorded with XY recorder."

"ABSTRAKTelah dibuat suatu sistem Magneto Optical Trap untuk mendinginkan dan memperangkap atom gas yang terdiri dari sepasang kumparan anti Helmholtz dengan 3 pasang cahaya laser pendingin yang dihasilkan dari satu laser dioda, dan satu laser lainnya digunakan sebagai laser pemompa-kembali (repumping laser). Atom Cs diletakkan dalam satu ruang oakum tinggi yang berada di tengah-tengah kumparan anti Helmholtz. Dengan bantuan sistem ini telah dapat diperangkap sekitar 107 atom Cs dan didinginkan sampai temperatur beberapa μK. Gumpalan awan atom ini dapat diamati dan foto luminesensi yang terjadi dalam awan yang didinginkan tersebut.Sifat-sifat dinamika awan atom Cs ini dapat dipelajari dengan mematikan atau mengubah frekuensi laser pendingin dan laser pemompa-kembali secara terprogram dan dengan mengamati luminesensinya. Dengan cara ini dapat dipelajari gejala transien, dan penjarangan populasi yang menyertainya.Selanjutnya telah dilakukan pengukuran temperatur dengan menggunakan metoda balistik yang sudah lazim dilakukan orang. Disamping itu telah dikembangkan cara pengukuran temperatur awan atom yang lebih teliti dengan menggunakan osilasi posisi dari awan atom dengan menggunakan medan magnet dari kumparan Anti Helmhotz yang berosilasi. Temyata metoda ini lebih dapat diandalkan dan hasilnya konsisten dengan metoda yang konvensional.

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ABSTRACT

A Magneto Optical Trap has been built consisting a pair of Anti Helmholtt coils with three pairs of cooling laser beams produced by one laser diode, and the other one for repumping. The Cs atom is placed in a high vacuum chamber located in the center of the anti Helmholtz coils. In this system about 107 Cs atoms have been trap and cooled to a temperature of a few μK. The cloud can be observed from the luminescence of the cooled atoms.

The dynamical properties of the cooled Cs atom has been studied by turning off or changing the frequency of the cooling laser and the repumping laser precisely for a short period and observing the luminescence of the cloud. In this way the characteristics of the transient phenomena of the cloud, such as the build up time, the pumping time and the density of the cooled Cs atoms can be studied.

The temperature of the cooled Cs atom in the cloud has been determined using the well known ballistic method. A new method for the measurement of the temperature of the Cs atoms has been developed. In this new method the position of the cloud is oscillated by a uniform oscillating magnetic field produced from a sinusoidal modulation added to the one of anti Helmholtz coils. The results turns out to be more reliable and the measurement result is consistent with the conventional method."