Doty's Nuclear Lab page is now under construction. New results are posted when the students do something (anything).

Dean Curzon has just spotted several students with equipment in front of the Library and is asking them what they are doing.

 

During stop week a group of hard core BioPhysics students decided to see if there was any radiation coming from the steps in front of the famous CSUN Library. While doing the measurement they were noticed by the Dean and she is asking them to see what is going on. The detector, protected from the sun under the black felt, did indeed find a form of radiation on Dean Curzon's steps. You may see that spectrum of Library Radiation below
Ms. Maritza Garcia collects data in the lab from an
  X-Ray defractometer
From basic physical properties the lattice spacing of LiF and NaCl were found to be 2.01 and 2.82 angstroms. With these values the K-alpha and K-beta transition energies were measured at 8.24 and 9.09 keV with agreement to 2.5%. The smaller peak at lower angle is the K-beta transition from the M to K shell. The more intense peak actually is a doublet from the L to K shell. Of the 3 levels in the L shell only 2P3/2 and 2P1/2 are allowed transitions. Their intensity ratio of 100 to 50 is explained by their spectroscopic notation.  

Data was taken by Gregory Frye on April 25, 2003.
A group of BioPhysics Majors test the radiation levels outside the Science I building at CSUN.
The students have just finished giving a Chi. Squared analysis of their Gaussian data taken several weeks ago. Today they took new data on the Poisson Distribution. A quote often used by one of the students ( closed eyes, Ms. Mavis Irwin is...." keeping an open mind is a virtue, but not so open that the brains fall out " -----James Olberg
Students visit the office of Chairman Julio Blanco. He is horrified to find that there is a sizable amount of radiation coming out from below his desk The mystery hands to the right are from the Nuclear Interpreter Kim ( American Sign Language Interpreter). The detector is sitting on his desk and is a high efficiency sodium iodide crystal coupled to a unique photomultiplier tube. It is totally powered by two AA cells and can be taken to remote sites easily. Although simple in theory to operate almost every use has resulted in some form of minor disaster such as not turning on when dignitaries are present or not turning off when the experiment is over.
  The radiation found in the Chairman's office is shown below. On the Y-axis is counts recorded in one hour and the lower X-axis is energy. The bump at the lower right is due to elemental potassium-40 which shows a strong gamma line at 1.46 MeV. There were about 9.3 events/sec. recorded at this energy in the volume of the detector. The broad continuum at the lower energy to the left is much more intense. Here the counts peak at about 100 keV and over 480 events/per second were detected. This type of graph is a linear representation of a differential energy spectrum
A group of Physics majors in the experimental techniques class have just turned on a portable detection system in the Deans office. They are measuring gamma radiation in the 10 KeV to 4 MeV region. The spectrum is recorded and stored in a small black box that easily fits into a person's pocket. The portable lap top is just to make the spectrum visible. They are specifically looking at a K-40 peak at 1.46 MeV. Both Biologists and Physicists are interested in potassium for people can not live without it since it is needed for neuron transmission in the human body. The students can take the spectral data home and study them at their leisure in a more relaxed atmosphere with their own computer.
Francis Appiah carefully moves a radioisotope from a lead pig and places it infront of a detector crystal.
Graduating student Berrie Goldman points out to Dean Curzon the presence of a gamma ray from the decay of radioactive Thorium found on the Library steps. This is an exceptionally high energy event that is capable even of creating antimatter! Looking on are Niccole Sansone and Mychica Simmons from the BioPhysics option. The Dean was impressed by the knowledge of the students who continued to explain that this type of radiation is present in most building materials, cement, rock and even the dirt in the San Fernando Valley region. The students are attempting to find if there are regions that are hotter or cooler from a radiation stand point.

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