1. A Nal(TI) detector is coupled to a photomultiplier tube having certain stages for electron multiplication. This detection system is used to detect g-rays of 1115 keV. The output circuit of photomultiplier has a capacitance of 250 pF. The average electron multiplication at each stage is 3. Assume light collection efficiency is unity, photocathode efficiency is 0.12 and 300 Ev energy is needed to create one photon and the amplitude of output pulse is 0.25 V. Find the number of multiplication stages in the photomultiplier. [Ans. 10]
Atomic Spectra
According to the Bohr model of an atom, the electron in an atom moves around a nucleus in fixed orbits with specific energies known as energy levels. The orbital energies are quantized. The electrons remain in these energy levels until they emit or absorb a photon of a particular wavelength, the quantum of energy. If the electron emits a photon, it then falls back to a lower energy level, and if it absorbs a photon, the electron rises to higher energy levels. The photons released or absorbed in these transitions of an electron are studied and analyzed on a screen as atomic spectra.
Ruby Lasers
Lasers are devices that emit light using atoms or molecules at a certain wavelength and amplify the light to produce a narrow beam of radiation. It works as per the principle of electromagnetic radiation. Their source of emission contains the same frequency and same phase. It was invented in the year 1960 by the great noble scientist, Theodore Maiman.
Balmer Series
The spectrum of frequency observed when electromagnetic radiation is emitted from an atom when it goes from higher energy state to lower state, is known as emission spectrum. This transition occurs when an excited electron moves from higher to lower state. It has many possible electron transitions and each transition has a specific energy difference.
Emission Spectrum
Every state of matter tries to be at minimum potential energy or it can be said that the atoms of element/ substance arrange themselves such that overall energy is minimum.
![1. A Nal(TI) detector is coupled to a photomultiplier tube having certain stages for electron
multiplication. This detection system is used to detect g-rays of 1115 keV. The output
circuit of photomultiplier has a capacitance of 250 pF. The average electron multiplication
at each stage is 3. Assume light collection efficiency is unity, photocathode efficiency is
0.12 and 300 Ev energy is needed to create one photon and the amplitude of output pulse
is 0.25 V. Find the number of multiplication stages in the photomultiplier. [Ans. 10]](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fa9d0a6bc-942b-4c2a-b852-fef0d6cefd95%2Ff1dc5d27-ecf3-4323-8be5-d4f4d46ebf06%2F11t12dx_processed.jpeg&w=3840&q=75)
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