Germanium Gamma Spectrometer Research Paper

4.γ spectroscopy

4.1 principle of the germanium gamma spectrometer

The germanium gamma spectrometer’s main part is a semiconductor detector. Semiconductor spectrometer is a radiation detector which use semiconductors as a detecting medium. The semiconductor detector has two electrodes with a certain voltage. When the particles come into the detector, it will form a pair of electron and an electron hole. Since the electrodes have a certain voltage, thus the electron will be forced to move in the circuit and form a pulse signal. Through this signal, the detector can collect the counts and get the result.

In the semiconductor detector, the sensitive band should be an ideal semiconductor. However, normal semiconductor materials have a relatively

Since the structure of strontium is similar with calcium, strontium can substitute the calcium in human bones. Thus the intake food that containing the elemnt will directly influence the concentration of elements in human body. The concentration can be greater to 100 to 1000ppm. [1] But the human bones are always exchanging nutrition and matters with the environment, so the strontium concentration in the bones will also change when the individual moves to another place. As estimated, in the compact bone, strontium isotopes’ turnover rate is about 3 percent each year, and in the cancellous bone, the isotopes’ turnover rate is about 26 percent each year. [8] The half turnover rate in bones is used to express the required time that half of the bone components are replaced. The rate of the compact bone is about 23.1 years, while the cancellous bone’s rate is just about 2.9 years. In the teeth, there are also strontium nucleuses. All the teeth are made of enamel, dentin and cementum components. Enamel is at the top of the teeth. It is the hardest part in human body. The main component of the enamel is hydroxylapatite. Conversely, there are no cells in the teeth, so after the formation of the teeth, the chemical composition of the teeth will not change any more. For instance, the strontium of children’s first molar enamels will not change after their formation between 1-year-old to 4-year-old. So assuming that an individual only consumed the locally grown food during his or her lifetime, the 87Sr/86Sr value in his tooth will reflect the individual’s childhood diet as well as his childhood locale. However, this ratio value in bones will reflect the adult diet and ideally the adult locale.