PPT-Labeling of DNA The SI unit of radioactive activity is the

becquerel Bq in honor of the scientist Henri Becquerel One Bq is defined as one transformation decay or disintegration per second Since sensible sizes of radioactive material contain many atoms a . Units Becquerel Bq 1 dps Curie Ci old unit 37 x 10 10 Bq exactl originally defined as the activity of 10 g of radium Exponential Decay Activity A of a rad oactive nuclide decreases exponentially with time Let N ato s present dN N dt The consta Fourth lecture. Discovery of radio activity. Radioactivity was the first nuclear phenomenon to be discovered , the credit for this discovery goes to the French physicist Henri Becquerel (1896) .. Radioactivity . ASTR 101. Prof. Dave Hanes. Think . About Clocks. They . are designed to . measure and mark the passage of . time, . by monitoring some regular, repeated mechanical action. . . There are Other Ways!. Definitions and types of decay. Derivation . of decay . e. quations. Half l. ives and mean lives. Secular . Equilibrium. Useful . radiotracers . in . oceanography. E & H . Chpt. 5. The chart of the nuclides - decay. Nuclear Stability . Nuclear stability . means that nucleus is stable meaning . that it . does not spontaneously emit any kind of radioactivity (radiation). . On the other hand, . if the . nucleus is unstable (not stable), it has the tendency of emitting some kind of . ASTR 101. Prof. Dave Hanes. Think . About Clocks. They . are designed to . measure and mark the passage of . time, . by monitoring some regular, repeated mechanical action. . . There are Other Ways!. Background Image courtesy of Dr. Bill Moore, Dept. of Radiology, Stony Brook Hospital. http://www.colin-studholme.net/research/ipag/mrdspect/mrspect3.html. http://www.mwit.ac.th/~Physicslab/applet_04/atom2/Alphae.gif. The number of atoms, . N. , remaining at a particular instant in time is given by: . A = . λ . N . Where . A . = the activity, The traditional unit for activity is called the curie (. Ci. )..  . 1 curie = 3.7 x 1010 disintegrations per second (. 53 1 Bq = 1 disintegration per sec. The accepted practice is to give the activity of a radioactive source in becquerel. This is because Bq is the unit chosen for the system of international units ( IMAGING In Vitro Versus In Vivo Red Cell Labeling on Image Quality in Gastrointestinal Bleeding Studies A.H. Maurer, J.L. Urbain, B. Krevsky, L.C. Knight, George Revesz and K. Brown Depart Rate of Radioactive decay with units. Geiger-Muller Counter. An atom is composed of positively charged nucleus that is surrounded by. negatively charged electrons.. The number of electrons is equal to the number of protons = Atomic Number. Rate of Radioactive decay with units. Geiger-Muller Counter. An atom is composed of positively charged nucleus that is surrounded by. negatively charged electrons.. The number of electrons is equal to the number of protons = Atomic Number. 1) Sign in. Print name legibly.. 2) Complete a ‘Radiation Worker Registration Form’, via:. . www.umaryland.edu. /ehs. 3) Complete online exam via . MyEHS. > Online Training > Radiation Safety. Where: . A . = Activity after some time t.. A. o. . = Original activity of the sample.. t . = Decay time . λ = the radioactive decay constant equal to . The half-life equation can be also used for activity, simply by replacing the number of atoms .