Search for Superheavy Elements in Nature by Detection of Events With Large Numbers of Neutrons. Page: 7 of 19
This report is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to Digital Library by the UNT Libraries Government Documents Department.
The following text was automatically extracted from the image on this page using optical character recognition software:
-4- jr' L9~'
p-terphenyl. Sixteen 5-inch Dumont.No. 6361, tx:iultipliers -are mounrd'on
glass viewing ports on two walls of the chamber. The inner'walls of the
chamber are painted with. white reflective coating. A tube for holding the
samples is located at the center of the chamber and has the dimensions of
11.4 cm diameter and 105 cm depth. The system is very similar to some .
described already in the literature.
Neutrons produced by any source placed at the center of the cham-
ber enter the liquid and are thermalized by collisions with the hydrogen
in the solution and eventually are either captured by the gadolinium or
leak out of the tank. The (n,' y) reaction in gadolinium produces
' 9 MeV of gamma energy, the- energy usually being shared by several gamma
rays. The electrons created by the reaction of these gamma rays with the
liquid produce scintillations which are seen by a. few of the photomulti-
The distribution in time for neutron capture is broad and has a
peak at about 10 jisec after the neutrons are emitted. About 90% of all the
neutrons are captured within 1-36 psec after their production. In this way
individual members of a burst of energetic neutrons ("'t 1 MeV) are separated
in time for convenient electronic multiplicity counting.
A simplified block diagram of the electronics is showm in Fig. 2.
The photomultipli.er pulses are summed in two banks (8 photomultipliers in
. each). A "tank pulse" is obtained when coincident pulses are observed from
banks A and B and when the linear sum of all photo multiplier outputs cor-
responds in pulse height to an energy greater than 1 MeV. This signal has
the significance that. the light must be seen by at least two photomultipliers
and have a.sum amplitude' corresponding to an energy greater than 1 MeV. Since
at least two photomultipliers must give a signal the effect of random noise
Here’s what’s next.
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Cheifetz, E.; Giusti, E. R.; Bowman, H. R.; Jared, R. C.; Hunter, J. B. & Thompson, S. G. Search for Superheavy Elements in Nature by Detection of Events With Large Numbers of Neutrons., report, January 1, 1970; [Berkeley, California]. (https://digital.library.unt.edu/ark:/67531/metadc866721/m1/7/: accessed May 20, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.