THICKNESS MEASUREMENT OF NON-METALLIC MATERIALS PROGRESS REPORT NO. 4

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03172A000300050046-5
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 5
• Document Creation Date: December 22, 2016
• Document Release Date: April 10, 2012
• Sequence Number: 46
• Publication Date: May 13, 1957
• Content Type: REPORT

Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
Project No. A-100
THICKNESS MEASUREMENT OF
NON-METALLIC MATERIALS
Progress Report No. 4
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
 Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
 Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
Project No. A-100
THICKNESS MEASUREMENT OF
NON-METALLIC MATERIALS
Progress Report No. 4
Copy No. May 13, 1957
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
 Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
THICKNESS MEASUREMENT OF
NON-METALLIC MATERIALS
L. INTRODUCTION
This is a report of the work done on Project No. A- 100
during the period of April I to April 30., 1957. The purpose of this
project is the development of an ultrasonic method for measuring thick-
ness in non-metallic materials. The material which has been the chief
concern to date is concrete, and the method most considered has been
the echo method, although a small amount of time during the last month
has been used to investigate the possibility of using the barium titanate
discs recently obtained as transducers in a resonance type thickness
measurement.
U. PRESENT WORK
Whatever method it used, it is important to have a transducer
which, in its mounting, is highly damped. This will allow the production
of short bursts of ultrasound for the echo technique or, alternately, will
insure the absence of a spurious reading in the resonance method. Much
of the time spent during the last month has been given to the investigation
of methods for obtaining this damping. Some of the more promising seem
to involve the use of a second ceramic transducer, similar to the actual
transmitter, which is placed on top of the transmitter, the boundary
between the two transducers being a common electrical contact. In one
experiment the top transducer bad its two faces shorted or connected
through a resistance while the bottom transducer was pulsed. In another
experiment the top and bottom faces of the transducer "sandwich" were
connected together to ground while the common faces received the pulse
from the generator. The best results were obtained when the polarities
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
 Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5
.2.
of the two transducers in the sandwich were opposite in direction. The
reason for this result is not obvious since, inasmuch as the fields on the
two transducers are also opposite in direction, the transducers should
oscillate in phase with each other.
M. FUTURE WORK
Is.
This last effect will be investigated during the next month as
a part of a continued investigation of damping. A new supplier of barium
titanate ceramics has been contacted and has promised to send several
samples for our investigation*,,
IV. NOTEBOOKS
The work reported here is beg recorded in Notebook
No. C-6629.
V. CONTRIBUTING PERSONNEL
The project is under the supervision of
The work on the transducers is being done by
Respectfully submitted,
and
0
7
MR
25X1
25X1
25X1
Declassified in Part - Sanitized Copy Approved for Release 2012/04/10: CIA-RDP78-03172A000300050046-5