Apparatuses and methods for laser reading of thermoluminescent phosphors

Patent · Sat Dec 31 23:00:00 EST 1988

OSTI ID:867002

Braunlich, Peter F ^[1]; Tetzlaff, Wolfgang ^[2]

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1. SW. 730 City View, Pullman, WA 99163
2. Pullman, WA

Apparatuses and methods for rapidly reading thermoluminescent phosphors to determine the amount of luminescent energy stored therein. The stored luminescent energy is interpreted as a measure of the total exposure of the thermoluminescent phosphor to ionizing radiation. The thermoluminescent phosphor reading apparatus uses a laser to generate a laser beam. The laser beam power level is monitored by a laser power detector and controlled to maintain the power level at a desired value or values which can vary with time. A shutter or other laser beam interrupting means is used to control exposure of the thermoluminescent phosphor to the laser beam. The laser beam can be equalized using an opitcal equalizer so that the laser beam has an approximately uniform power density across the beam. The heated thermoluminescent phosphor emits a visible or otherwise detectable luminescent emission which is measured as an indication of the radiation exposure of the thermoluminscent phosphors. Also disclosed are preferred signal processing and control circuits including one system using a digital computer. Also disclosed are time-profiled laser power cycles for pre-anneal, read and post-anneal treatment of phosphors.

• Research Organization: INTERNATIONAL SENSOR TECHNOL
• DOE Contract Number: AC03-84ER80165
• Assignee: Braunlich; Peter F. (Pullman, WA) [*] Notice: portion of term of this patent subsequent to January 20, 2004 has been disclaimed.
• Patent Number(s): US 4839518
• OSTI ID: 867002
• Country of Publication: United States
• Language: English

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/250/
amount
apparatus
apparatuses
approximately
approximately uniform
beam
beam power
circuits
circuits including
computer
control
control circuit
control circuits
controlled
cycles
density
desired
desired value
detectable
detector
determine
digital
digital computer
disclosed
emission
emits
energy
energy stored
equalized
equalizer
exposure
generate
heated
including
indication
interpreted
interrupting
ionizing
ionizing radiation
laser
laser beam
laser power
level
luminescent
luminescent emission
luminescent energy
luminescent phosphor
maintain
means
measure
measured
methods
monitored
opitcal
otherwise
phosphor
phosphor emits
phosphors
post-anneal
power
power cycle
power density
power level
pre-anneal
preferred
processing
radiation
radiation exposure
rapidly
rapidly reading
reading
reading thermoluminescent
shutter
signal
signal process
signal processing
stored
stored luminescent
stored therein
therein
thermoluminescent
thermoluminescent phosphor
thermoluminescent phosphors
thermoluminscent
time
time-profiled
total
treatment
uniform
value
values
vary
visible