NBSIR 75-654

NBS InterAgency Transducer Project

A Project Report

p. S. Lederer and J. S. Hi I ten

Electronic Technology Division

Institute for Applied Technology

National Bureau of Standards

Washington, D. C. 20234

February 20. 1975

Progress Report Covering Period July 1, 1974 to Semptember 30, 1974

Prepared for Naval Air Systems Command

U.S. Navy and Transducer Committee

Telemetry Group

Range Commanders Council

NBSIR 75-654

NBS INTERAGENCY TRANSDUCER PROJECT

A PROJECT REPORT

p. S. Lederer and J. S. Hilten

Electronic Technology Division

Institute for Applied Technology^

National Bureau of Standards

Washington, D. C. 20234

February 20, 1975

Progress Report Covering Period July 1, 1974 to September 30, 1974

This is a progress report. The work is incomplete and is continuing.

Results and conclusions are not necessarily those that will be included

in a final report. Performance test data were obtained from one or two

samples of several transducer types, and do not necessarily represent

the characteristics of all transducers of a given type.

Prepared for Naval Air Systems Command

U.S. Navy and Transducer Committee

Telemetry Group

Range Commanders Council

U. S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director
NBS InterAgency Transducer Project

A method is being developed to apply short-duration thermal

transients to pressure transducers and to observe the effects of

these transients on transducer performance. The method consists

of monitoring pressure transducer output as the transducer is

exposed to radiation resulting from the ignition of a photographic

flashbulb or from the discharge of an electronic flash. During

this reporting period, the work has been exploratory in nature to

determine values for method parameters. Thermal energy pulses as high as 0.4 J lasting 4 ms have been generated using an electronic

flash; pulses as high as 1 J lasting 18 ms have been generated

using #22 flashublbs.

Work being performed for other agencies is also described

briefly.

Key words: Calibration; dynamic; photo flashbulb; pressure;

pressure measurement; pressure transducer; thermal transient;

transducer.
NBS InterAgency Transducer Project

Progress Report for the Period

From July 1, 1974 to September 30, 1974

to the

Naval Air Systems Command,

U.S. Navy Transducer Committee,

Telemetry Group,

Range Commanders Council

NBS Project 4253434

Prepared by

Paul S. Lederer

and

John S. Hilten

A method is being developed to ipply short-duration

thermal transients to pressure transducers and to observe

the effects of these transients on transducer performance.

The method consists of monitoring pressure transducer output as the transducer is exposed to radiation resulting

from the ignition of a photographic flashbulb or from the

discharge of an electronic flash. During this reporting

period, the work has been exploratory in nature to determine values for method parameters. Thermal energy pulses

as high as 0.4 J lasting 4 ms have been generated using an electronic flash; pulses as high as 1 J lasting 18 ms have

been generated using #22 flashbulbs.

Work being performed for other agencies is also

described briefly.

Key words: Calibration; dynamic; photo •f'lashbulb; pressure;

pressure measurement; pressure transducer; thermal transient;

transducer.

1. Introduction

1 .1 Background

The NBS InterAgency Transducer Project has been supported by

various agencies of the Department of Defense and NASA between 1951 and

1972. Agency budget restrictions in FY 1973 forced the discontinuance

of the project during that year. The Transducer Committee of the Range

Commanders Council Telemetry Group (TG/RCC) obtained some support from
national test ranges for the resumption of this project in FY 1974, and

the Naval Air Systems Command resumed its support in FY 1975.

Current objectives of this project are the following (the

first four objectives have been pursued since the inception of the

original project in 1951):

1.1.1 Investigation of the Performance Characteristics of

Telemetering Transducers

1.1.2 Development of Calibration and Evaluation Techniques

and Apparatus for Telemetering Transducers

1.1.3 Evaluation of New Transducer Technologies for

Telemetry

1.1.4 Consultation to Navy Research, Test, and Evaluation

Facilities and Test Ranges

1.1.5 Support of Range Commanders Council, Telemetry

Group, in Investigations and Development of

Transducer Standards for Telemetry

1 .2 NBS InterAgency Transducer Project

In order to supplement the variable funding made available

specifically for the NBS InterAgency Transducer Project, support has

been sought from other agencies to fund certain mission-oriented tasks.

These tasks have generally met one or more of the objectives of the

InterAgency Project as well. Therefore, reports describing the missionoriented work have been made available to the Naval Air Systems Command,

to national test ranges, and to other interested agencies and their

contractors. Plans are to continue this policy.

1 . 3 Current Assignment

The Transducer Committee of TG/RCC has assigned the following

task to the NBS InterAgency Transducer Project: "Develop a test device

and gener'ate a test procedure to impinge thermal transient inputs on pressure transducers. The requirements of the test device should

include:

1. Inexpensive to build;

2. Simple to operate;

3. Easily reproducible by transducer manufacturers,

- . test ranges, or range users;

4. Capable of impinging thermal transients of any

duration greater than 1 millisecond;

5. Controlled heat flux inputs capable of being

quantized.

2
Documentation of this test procedure and the devices constructed should

be formalized in report form. In addition, this report should relate

the heat flux capabilities of the test device to actual thermal transient

environments. Quarterly progress reports should be submitted to the

TG Transducer Committee."

2: Experimental Development

2.1 Introduction

A method for generating and applying thermal transients to

pressure transducers was described in an oral presentation to the Task

Group Executive Committee and to the Transducer Committee at the July

1974 TG/RCC meeting. The method, in brief, consists of monitoring

transducer output as the transducer is exposed to radiation resulting

from the ignition of a photographic flashbulb or from the discharge of

an electronic flash. Experimental work began vihen the energy meter and

electronic flash were received in September 1974, Most of the work has

been exploratory in nature to determine values for method parameters.

2 . 2 Method and Arrangement of Apparatus

The experimental arrangement is as follows: The flashbulb

or flashtube is mounted in a vertical position at the center of an optical bench; mounted on the bench on opposite sides are an energy

meter and the transducer mounting fixture. The diaphragm of the mounted

pressure transducer and the sensing element of the energy meter are aligned with, and equidistant from, the center of the flash unit. The

energy meter and transducer may be moved along the bench to vary the

respective distances between them and the flash unit, which is held

fixed. Also fixed in position is a photodiode mounted at right angles

15 cm from the bench center and used as a flash output monitor to check

the operation of the energy meter. The output for a given flash is

assumed to be constant in azimuth to with 5%. All four elements are adjusted in position vertically to be coplanar.

In a test the quantities monitored are as follows: (1) the

output of the pressure transducer displayed on an oscilloscope, (2) the

digital reading of the energy meter (which displays the total pulse

energy in joules), (3) the energy meter output displayed on an oscilloscope (peak amplitude is proportional to the energy input), and (4) the

photodiode output also displayed on an oscilloscope.

2.3 Equipment Description

2.3.1 Transducer Mounting Fixture

The transducer mounting fixture is a rectangular brass

block approximately 10-cm high, 10-cm wide, and 6-cm deep and is purposely

made massive to serve as a heat sink, with a mass of about 5 kg. A 3.8-

cm bore extends through the block, centered on the front face (the face

towards the flash unit). A round glass window with an aperture of 3 cm

3
and a thickness of approximately 0.6 cm is sealed into the bore at the

front face. The window glass is of a 96%-silica composition with a low coefficient of expansion. The transducer to be tested is mounted

in a brass flange; an air-tight seal to the bore is made by means of an

0 ring between the flange and the block. The flange is mounted to the

block with 6 bolts. This arrangement simulates the way a transducer is

mounted in a typical application.

A hole connecting with the bore permits any desired

pressure (including vacuum) to be applied to the volume between the

transducer and window. Thus, the pressure the transducer sees at the

beginning of a run may be preselected.

2^.3.2 The Energy Meter

The following information is abstracted from the

manufacturer's instruction manual: The energy meter consists of a pyroelectric detector and associated signal -processing and display

electronics. The pyroelectric detector is a slice of ferroelectric

material which possesses a permanent electric polarization that is

highly temperature dependent. As radiant energy is absorbed by the

detector coating, a current is generated that is proportional to the

time-rate-of-change of the temperature of the ferroelectric material.

This current is integrated by a preamplifier and produces an output

that can be displayed on an oscilloscope. The peak amplitude of the

preamplifier output waveform is proportional to the energy content of

the radiation pulse. The readout circuitry measures the peak amplitude

of the preamplifier output, computes a scale factor, and displays the

result in the proper units (joules).

The meter, with four-digit readout, is intended to

measure the total energy content of radiation pulses with durations

ranging from less than 1 ns up to a maximum of 50 ms. This range of

pulse durations represents a modification of the standard meter, which

covers a L-ns to 1-ms range.

Seven ranges are provided, which are switch selectable, with full-scale readings progressing in six decade steps from

2 yj to 200 mJ in addition to a 1-J position.

The response of the pyroelectric detector is

described as being flat to within ±2% in the wavelength range of from

0.3 ym to 20 ym. Manufacturer's literature describes the overall system

accuracy as ±4% of reading ±1% of full scale with the sensing area fully

illuminated. Least count is 0.1 mJ for 200 mO full scale and 0.001 yJ

for 2 yJ full scale. Maximum noise level is given as 0.3 yJ.

In the auto-trigger mode, the instrument is triggered

when the energy absorbed by the detector is greater than 5% of full scale;

in the external -trigger mode, a positive-going trigger pulse ranging in

amplitude from 5 V to 100 V must be supplied coincident with the

radiation pulse to be measured.

4
2.3.3 Flashbulbs

Three types of photographic flashbulbs have been or

will be used in the evaluation; their characteristics, obtained from

manufacturer's literature, are shown in table 1.

Table 1

Flashbulb Characteristics

Bulb

Designation

# 5 clear

#22 clear

FF-33

Flashbulb

Output

(klm-s)

20

70

not given

Peak Luminous

Flux (klm)

1450

4200

120

Approximate

Time to Peak

(s)

0.020

0.020

0.640

Approximate

Duration of

Flash (s)*

0.019

o.oia

1.6

*Time measured from point when flash reaches 30% of its maximum value

until it falls to 30% of its maximum value

The #5 and #22 flashbulbs are readily available from

photographic supply houses; the FF-33 flashbulb, or "flood flash" as it

is described by the manufacturer, is used in automotive crash-test

photographic applications and can be purchased directly from the

manufacturer.

The amplitude-time waveform of the radiation output

from all three bulbs is roughly triangular in shape.

2.3.4 Description of Electronic Flash System

The electronic flash system consists of a xenonfilled flash tube, a capacitor bank, a power supply, and other associated

electronic components including a triggering circuit. In use, the

capacitor bank is charged by the power supply to approximately 450 V dc;

the voltage is then discharged through the flash tube by applying a trigger pulse to the gate of a silocon controlled rectifier by means of

a mechanical switch.

This unit can operate at one of two energy levels,

150 and 50 J; in the 150-J mode the peak intensity of the light is only

slightly increased over the 50-J mode, but the capacitor discharge time

is extended. The rise time is about 0.3 ms for both the 50- and 150-J

positions, but the fall time to about 30% of the peak value is about

2 ms and 4 ms, respectively. The manufacturer describes the color content

of the light as very closely resembling that of daylight.

5
2.3.5 Photodiodes

The n-p-n planar silicon phototransistor selected

may be used in either the phototransistor mode or the photodiode mode

of operation; in all tests described in this report the photodiode mode

was used. The manufacturer gives the rise time and fall time as typically 350 ns and 500 ns, respectively. The output collector current is

linear with irradiance from 0 to 80 mW/cm^, The spectral response is near zero at 0.5 ym, rises to a maximum at about 0,9 ym, and returns to near zero at 1.1 ym. A supply voltage of up to 50 V dc may be used in

the photodiode circuit.

2.4 Description of Work

' The approximate amount of energy available from the electronic

flash at the 15(J-J setting was measured with the energy meter a few cm away from the flash (within the range over which there was little variation observed with change in meter-flash distance). A level of from

0.3 J to 0.4 J was measured by the l-cm^ circular sensing area of the

energy meter. Using the same experimental arrangement with a #22

flashbulb, approximately 1 J was measured.

Some indication of repeatability of the flash energy was obtained by firing twenty consecutive shots with the electronic flash

first at the 50-J setting and then at the 150-J setting (meter-flash

distance of approximately 25 cm). With 50-J, the sample standard

deviation for twenty flashes was 1.51 mJ, and the sample mean 63.99 yJ;

with 150 J, (excluding three shots which apparently misregistered), the

sample standard deviation was 2.29 mJ, and the sample mean 109.15 mJ.

Much of this variation is not scatter but a gradual decline in measured

values observed as the tests proceeded.

Tests in which the flash was fired five times with the energy

meter open, then fired an additional ten times with the energy meter

shuttered, and finally fired five more times with the energy meter

uncovered indicate that this decline results from the performance of

the electronic flash. Flash output apparently drops as the internal

battery voltage drops with use. A line-operated power supply has been

ordered to eliminate this problem. Energy-meter malfunctions are occurring about 10% or 15% of the time, and considerable effort has

been expended to determine the cause and to find a correction; faulty

triggering of the energy meter is suspected.

With respect to flashbulb repeatability, the sample standard

deviation for six #5 flashbulbs was 2.77 mJ (sample mean 42.12 mJ), and

for six #22 bulbs, 5.47 mJ (sample mean 87.18 mJ). No FF-33 bulbs are available at this time.

Because of problems with the energy meter and with the

battery-operated flash units, insufficient data is available to

establish the relationship between distance and energy level. No

transducers have been used in thermal transient tests in this period.

6
3. Plans tor the Reporting Period October 1, 1974 to December 31, 1974

3.1 Energy-Distance Dependence

The change in measured energy density as a function of

distance from the flash will be determined by measuring flash energy

with the distance from the meter to the flash varied from 1 cm to 15 cm

in 1-cm steps. Sets of measurements will be taken for five flash sources:

#5 flashbulbs, §22 flashbulbs, FF-33 flood flashbulbs, electronic flash

set for 50 J, and electronic flash set for 150 J. During these tests

the output of a pressure transducer known to be affected by thermal

transients will be measured at the time of each flash. For each position, the transducer-flash distance will be made equal to the meterflash distance. The monitoring photodiode will also be used in these

tests. The data obtained will be used to guide the selection of a convenient test distance.

3.2 Method Repeatability

Repeatability of the method will be esttmated on the basis of

the following experiment. The transducer used in 3.1 and the energy meter

will be set at the selected distance from the flash, and ten flashes fired

with a two-minute interval between flashes. Transducer response, photodiode output, and the two outputs from the energy meter will be measured

and recorded. This test will be carried out for the five flash sources identified in 3.1

.

3.3 Pressure Transducer Response Measurements

Response of sixteen selected pressure transducers to thermal

transients will be determined at the test distance and with several of

the flash sources identified in 3.1.

Six types of transducer will be represented, as follows:

recessed diaphragm (four), industrial -use type semiconductor strain

gage (four), unbonded strain gage (one), thin-film deposited strain

gage (three), metal -diaphragm semiconductor strain gage (one), and

ceramic-diaphragm semiconductor strain gage (three). The gage pressure

range for these transducers is from nominal zero to 345 kPa (50 psi).

Distances other than the test distance may also be used,

and tests involving FF-33 flashbulbs may be abbreviated if sufficient

flashbulbs are not available. The quantities to be measured and

recorded will be those of 3.2

3.4 Other Experimental Work

In addition to the work described above, the following

experiments are planned:

7
: 1. Measurement of the response of selected transducers

to energy Incident at an angle other than normal to

the exposed surface,

2. Measurement of the response of selected transducers

with the transducer itself measuring full-scale

pressure,

3. Measurement of the response of selected transducers

with the transducer itself measuring vacuum pressure,

4. Measurement of the energy transmission loss through

a glass window and window reflection coefficient,

5. Determination of the effect of aperture size on the '^ ; energy measurement,

6. Measurement of the effect of line-voltage changes

on electronic flash energy,

^^'i 7. Measurement of the effect of battery-voltage changes

on flashbulb energy, and

8. Measurement of the output of selected semiconductor

strain-gage pressure transducers when exposed to

thermal transients and with no transducer (electrical)

excitation.

4. Other-Agency Work

During FY 1974, several tasks were in progress for other government

agencies outside the NBS InterAgency Transducer Project. Since the

objectives of each of these tasks fall within the area of the NBS

InterAgency Transducer Project, abstracts of appropriate project reports

are given:

4.1 Vezzetti , C.F., and Lederer, P.S., An Experimental Method

for the Evaluation of Thermal -Transient Effects on Piezoelectric Accel erometers , NBS Tech Note 855 (November

1974)

A simple, inexpensive method was developed for determining

the effects of thermal transients on the zero output and sensitivity

of piezoelectric accel erometers. Thermal transients are generated by

an incandescent lamp and can be made to heat the top or side of the test

accel erometer. Fourteen commercial accel erometers were tested using

this technique. Zero shifts with magnitudes as high as 640 gj] were

observed. Zero shifts of up to 2% of full scale resulted from 1-s

duration transients, and up to 7% of full scale from 15-s transients.

These results were obtained at a radiation power density of 1.8 W/cm^.

No changes of accel erometer sensitivity exceeding experimental

uncertainties were noted as a result of the thermal transients used.

8
4.2 Development of a Dynamic Pressure Calibration Method

4.2.1 Vezzetti, C.F., Lederer, P.S., and Hilten, J.S.,

Development ot a Dynamic Pressure Calibration

Technique-Progress Report for the Period

^ September 15, 1973 to February 15, 1974, NBSIR

74-503(R) (June 1974)

The objective of this task is to develop a dynamic

pressure calibration technique yielding a flat frequency response to

2000 Hz or greater and amplitude capability of at least 34 kPa (5.0 psi)

zero-to-peak. Equipment was set up, a universal test fixture fabricated,

and testing was initiated of various liquids and damping schemes for a hydraulic sinusoidal pressure generator consisting of a vibrating liquid

column. Two liquids of density greater than water, tetrabromoethane and

a fluorocarbon, were tested. As was expected from the densities and

bulk moduli, improved frequency response could be accomplished only with

the tetrabromoethane. Very little improvement of damping has been

obtained by using tubes with large wetting surface area. Although tests

using filters are only in early stages, indications are that the proper

combination of liquid viscosity and filter porosity may result in

improved damping.

4.2.2 Vezzetti, CP., Hilten, J.S., and Lederer, P.S.,

Development of a Dynamic Pressure Calibration

Technique-Progress Report for the Period February

15, 1974 to August 15, 1974, NBSIR to be published

This progress report describes continuing development

of methods for the dynamic calibration of pressure transducers. The

requirements are for the generation of a sinusoidal ly varying test

pressure of at least 34 kPa zero-to-peak with a permitted variation in

peak amplitude not to exceed ±5%. The pressure-generating system is to

have an upper frequency capability of at least 2 kHz; no lower frequency

capability requirement is specified. Vibration at ±36 g^^ of a tube

filled with dimethyl siloxane liquid and mounted on the armature of a vibration exciter has generated pressures of 34 kPa zero-to-peak over

the frequency range of from 40 Hz to 750 Hz. A method of damping the

movement of liquid in the tube by packing the larger main tube with a number of smaller tubes is described.

4.3 Space Shuttle Pogo Pressure Measuring System

4.3.1 Lederer, P.S., and Hilten, J.S., Space Shuttle

Pogo Pressure Measuring System-Progress Report

for the Period September 15, 1973 to December 15,

1973, NBSIR 75-560 (February 1975)

This progress report describes continuing development

of methods for the dynamic calibration of pogo pressure transducers used

to measure oscillatory pressures generated in the propulsion system of

9
the space shuttle. The requirements are for the generation of a known

(5% or better) sinusoidal pressure perturbation of 140 kPa (approximately

20 psi) peak-to-peak at bias pressures up to 55 MPa (approximately 8000

psi) over a frequency range of from 1 Hz to 100 Hz, Rotation of a mercury-filled column in the vertical plane at frequencies of lu Hz and

- below has produced peak-to-peak pressures of 39 kPa (5.7 psi) at bias

pressures of up to 55.4 MPa (803U psi). Evaluation of some variableimpedance, semiconductor strain-gage, piezoelectric, and metallic straingage pressure transducer systems for suitability as pogo sensors is

described.

4.3.2 Hilten, J.S., and Lederer, P.S., Space Shuttle

Pogo Pressure Measuring System-Progress Report

^ « for the Period December 15, 1973 to June 15,

'•- ^ - : . 1974, NBSIR 74-604 (December 1974)

This progress report describes two methods for the < dynamic calibration of pogo pressure transducers used to measure

oscillatory pressures generated in the propulsion system of the space

shuttle. The requirements are for the generation of a known (5% or better) sinusoidal pressure perturbation of 140 kPa (approximately 20

psi) peak-to-peak at bias pressures up to 55 MPa (approximately 8000 psi) over a frequency range of from I Hz to 100 Hz. Rotating a mercury-filled

column in a vertical plane at frequencies below 10 Hz generates peak-topeak pressures of 48 kPa (7.0 psi); vibrating the same mercury-filled

column in a vertical plane continues the frequency response from 10 Hz

to 200 Hz at peak-to-peak pressures ranging -from 21 kPa to 145 kPa

(approximately 3 psi to 21 psi). A method for vacuum filling of the

column is described.

5. Transducer-Related NBS Publications

A variety of activities at NBS related to transducers and their

calibration results in publications. In order to enhance the dissemination of this information, abstracts are presented below of some of the

recent publications in this area.

5.1 Koyanagi , R.S., Pollard, J.D., and Ramboz, J.D., A

Systematic Study of Vibration Transfer Standards —

Mounting Effects, NBSIR 73-291 (September 1973)

The purpose of this study was to determine the extent of the

sensitivity change of laboratory quality piezoelectric accelerometers

for various mounting conditions. The mounting variables included the

material upon which the accelerometer was mounted; geometry, the use

of commercial insulated studs, and the use of mounting stud thread

size adaptors. For the stated test conditions, the effect of different

materials and geometry was insignificant below about 300U Hz. For

stainless steel, beryllium, alumina, and tungsten, the deviations were

less than 0.5 percent up to 10000 Hz. The aluminum alloy base showed

an increase of about 2 percent at lOOOU Hz. The effect of insulated

10
studs showed deviations beginning at about 3000 Hz. No significant

deviation was found between the different stud thread size adaptors.

5.2 Ramboz, J.D., and Federman, C, Evaluation and Calibration

of Mechanical Shock Accel erometers by Comparison Methods,

NBSIR 74-480 (March 1974)

A means to calibrate mechanical shock accel erometers by a comparison method has been developed. Detailed procedures and equipment

used to generate mechanical shock pulses, collect data, and analyze the

results are discussed. Three accel erometers were subjected to haversine

acceleration-time pulses of 50-, 500- , 900- , and 1500-^^ peak amplitudes

and time durations of 8.5, 1.2, 1.2, and U.7 ms, respectively. Both timeand frequency-domain calibrations were performed. The shock calibrations

agreed with sinusoidal values to within a few percent. Problems

encountered and future developments are discussed.

5.3 Ramboz, J.D., Absolute Calibration of Vibration

Standards by the Three-Mass Reciprocity Method

»

NBSIR 74-481 (April 1974)

Reciprocity calibration of electrodynamic vibration exciters

is reviewed. A new method is proposed. The theory for the new ThreeMass reciprocity calibration method is developed. The process requires

that the electrical impedance of the exciter's drive coil be measured

for three added masses separately mounted on the exciter's armature.

The sensitivity of the accelerometer mounted in the armature is solved

in terms of a change of electrical impedance for a change of mass,

voltage ratio, electrical resistance, and frequency. A set of 38

measurements were made at 1000 Hz to experimentally verify the theory.

The value of sensitivity was 2.070 pC/^n percent. This agreed to

within about ±0.65 percent of a transfer calibration from Bouche-Levy

calibrated standards and the manufacturer's estimated value. Measurements were made to verify the theory; improvement to an uncertainty of

about ±0.2 percent is ultimately possible in the absolute calibration

using this method.

5.4 Olsen, L.O., Introduction to Liquid Flow Metering and

Calibration of Liquid Flow Meters, NBS Tech Note 831

(June 1974)

These notes are intended to serve as an instruction manual for

technicians and engineers engaged in metering liquids and calibrating

liquid flowmeters. It is a condensed review of the properties of

liquids and the mathematical relations required in this work. References

to more complete sources of properties of liquids, theoretical relations

and instructions for metering liquids are included. Separate chapters

discuss liquids and their properties as they affect flow, the theory of

incompressible flow of liquids and the measurements required in the

metering of liquids. One chapter describes several dii'ferent apparatus

n
and their use in the calibration of liquid flowmeters. The last

chapter contains brief descriptions of the many types of flowmeters

such as differential pressure, positive displacement, electromagnetic and ultrasonic. It also includes a discussion of the

physical principles involved in their design and use.

USCOMM-NBS-DC

12
NBS-114A IREV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. IH!IM.IC A I ION OR REPORT NO. NBSIR 75-654

No.

3. Recipient's Accession No.

4 . 1 i i 1 . I . -T. A 1 J > L ' It i 1 I i , 1 .

NBS InterAgency Transducer Project

A Progress Report

5. Publ ic at ion Date February 20, 1975

6. I'^erforming Organ i zat i()n Gode

7. AUTHOR(S)

Paul S. Lederer and John S. Hi 1 ten

8. Performing Organ. Report No.

9. PKRFORMING ORGANIZATION NAME AND ADDRKSS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

w"AonlNUiUN, A cu 1 u T r\kj n oaot.< U.L. zUzJ4

10. Project/Task/'*ork Unit No. 4253434

11. Contract/Grant No.

12. Sponsoring Org.inization Nami- and ( ompletc Address (Street, City, State, ZIP)

Naval Air Systems Command Transducer Committee T6/RCC

Wasninton, D.C. 20361 c/o Div. 9486

Sandia Laboratories

Albuquerque, NM 87115

13. Type of Report & Period Covered Interim

7/1/74 to 9/30/74

14. Sponsoring Agency Codi

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less tactual summary of most sigriificant information. If document includes a significant

bibliography or literature survey, mention it here.) A method is being developed to apply short-duration thermal transients to

pressure transducers and to observe the effects of these transients on transducer performance. The method consists of monitoring pressure transducer

output as the transducer is exposed to radiation resulting from the ignition

of a photographic flashbulb or from the discharge of an electronic flash.

During this reporting period, the work has been exploratory in nature to

determine values for method parameters. Thermal energy pulses as high as 0.4 J lasting 4 ms have been generated using an electronic flash; pulses as high as 1 J lasting 18 ms have been generated using #22 flashbulbs.

Work being performed for other agencies is also described briefly.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key nord unless a proper name; separated by semicolons

)

Calibration; dynamic; photo flashbulb; pressure; pressure measurement;

pressure transducer; thermal transient; transducer.

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