This research was sponsored by the National Science Foundation Grant NSF PHY 87-1440

Anderson, B.D.

Baldwin, A.R.

Madey, R.

Sellers, R.N.

Watson, J.W.

English

IUScholarWorks

DETECTOR DEVELOPMENT 
HIGH-EFFICIENCY NEUTRON DETECTORS 
R. Madey, R.N. Sellers, A.R. Baldwin, B.D. Anderson, and J.W. Watson 
Kent State University, Kent, Ohio 44242 
During the past year, we compared the performance 
at the IUCF of a high-density (p = 4.88 g/cm3) 
barium-fluoride (BaF2) scintillator with a liquid 
(CH2), scintillator (p = 0.858 g/cm3). By comparing 
the counts observed in the 12~(g.s.) peak from the 
12~(p,n) reaction at 135 MeV, the efficiency per unit 
volume of the BaF2 (as extracted on-line) appeared to 
be 3.3 times that of the (CH2), scintillator. Since 
86% of the neutrons interact in traversing two 
mean-free-paths, it appears that a high-efficiency 
("86%) neutron detector can be achieved with a BaF2 
thickness of about 40 cm. The observed efficiency 
sections. We made a few measurements of the light 
output of the BaF2 and (CH2), scintillators in response 
to proton energy losses from about 40 to 90 MeV. 
Preliminary results show that light output from BaF2 
is higher than that from NE-102 plastic, whereas the 
light output from the (CH2), scintillator is lower than 
that from NE-102 plastic. The overall time resolution 
for neutrons of about 118 MeV in the 12~(g.s.) peak was 
broader for the BaF2 than for the (CH2),; however, at 
this time it is not clear whether this result was 
caused by degradation of the fast component in the BaF2 
or whether neutrons do not excite the fast component as 
ratio of about 3.3 is consistent with that expected on effectively as photons. Further tests are needed. 
the basis of geometric neutron interaction cross 
USE OF AXIAL GAS-IONIZATION CHAMBERS TO STUDY INTERMEDIATE-MASS-FRAGMENT PRODUCTION IN NUCLEAR WACTIONS 
D. Bonser, K. Kwiatkowski, S. Rose, and V.E. Viola 
Indiana University Cyclotron Facility, Bloomington, Indiana 47405 
Two new designs for gas ionization chambers were 
constructed and tested. They are both based on an 
axial anode configuration. Figure 1 is a schematic of 
a multi-anode design. The anodes and electrodes are 
annular rings. The anode is operated at a high 
voltage and every other electrode is grounded. Because 
of the short distance an ionization electron travels to 
the collecting electrode (anode) in this design, the 
detector produces very rapid electron collection. 
Resolution (full-width at half-maximum, FWHM) of an 
241Am source (5.48 MeV alpha) was found to be .31 MeV 
9 5 
at a gas pressure of 45 Torr (CF4) and an applied 
voltage on the anode of 450 volts. In a run with a 200 
MeV 4 ~ e  beam incident on a nat~g target this detector 
yielded an overall charge resolution of 0.43 Z units, 
permitting mass identification of 7 ~ e  and '~e (see 
Fig. 2). 
A second design included shaping electrodes which 
produce a more uniform electric field (Fig. lb). 
Again, the single anode as well as the shaping 
electrodes are annular rings. The anode is in the 
middle and is operated at a high voltage. The entrance 


High-Efficiency Neutron Detectors

https://scholarworks.iu.edu/dspace/bitstream/2022/940/1/iucf_1986_95.pdf

High-Efficiency Neutron Detectors

Abstract

Similar works

Full text

Available Versions

IUScholarWorks