IP Library Granted Patent US 8,648,317
Granted Patent B2
US 8,648,317 · App. 12/757,194 · Granted Feb 11, 2014

Reading mechanism for dosimeter

Inventors: R. Craig Yoder (Crown Point, IN); Mark S. Akselrod (Stillwater, OK); Yoshikazu Tatsumi (Chicago, IL); Tse-Min Lo (Glenwood, IL)
Assignee: Landauer, Inc.
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Quick Facts
Patent No.
US 8,648,317
App. No.
12/757,194
Granted
Feb 11, 2014
Kind
B2
Abstract

Described is a method comprising the following steps: (a) moving a selected optically stimulated luminescence (OSL) sensor of two or OSL sensors mounted on a dosimeter sled to a reading position for an OSL reader; (b) reading the selected OSL sensor at the reading position using the OSL reader to measure a radiation dosage to which a dosimeter in which the dosimeter sled has been mounted has been exposed; and (c) repeating steps (a) and (b) for each of the two or more OSL sensors, wherein each OSL sensor comprises an optically stimulated luminescent material (OSLM) mounted in one or more cylindrical cup-shaped energy compensating filters, and wherein the dosimeter sled is part of a dosimeter.

Claims (47)

1. A method comprising the following steps:

(a) moving a selected optically stimulated luminescence (OSL) sensor of two or more OSL sensors mounted on a dosimeter sled to a reading position for the selected OSL sensor;

(b) reading the selected OSL sensor at the reading position using an OSL reader to measure a radiation dosage to which a dosimeter in which the dosimeter sled has been mounted has been exposed; and

(c) repeating steps (a) and (b) for each of the two or more OSL sensors,

wherein each OSL sensor comprises an optically stimulated luminescent material (OSLM) mounted in one or more cylindrical cup-shaped energy compensating filters, and

wherein the dosimeter sled is part of a dosimeter.

2. The method of claim 1 , wherein the two or more OSL sensors comprises: a first OSL sensor and a second OSL sensor, wherein a first radiation dosage of neutron, x-ray and gamma ray radiation for the dosimeter is measured from the first OSL sensor and wherein a second radiation dosage of x-ray and gamma ray radiation for the dosimeter is measured from the second OSL sensor.

3. The method of claim 2 , further comprising the following step:

(d) determining a neutron radiation dosage to which the dosimeter has been exposed based on the first radiation dosage and the second radiation dosage.

4. The method of claim 3 , further comprising the following step:

(e) reading an RFID tag that is part of the dosimeter sled to obtain information that may be used in determining the neutron radiation dosage in step (d),

wherein the neutron radiation dosage determined in step (d) is based on the information obtained from the RFID tag in step (e).

5. The method of claim 3 , further comprising the following step:

(e) determining the amount stimulation light used in conducting step (a),

wherein the neutron radiation dosage determined in (d) is based on the amount of stimulation light determined in step (e).

6. The method of claim 3 , further comprising the following step:

(e) determining the amount of non-radiation induced light received by the OSL reader conducting step (b) for use in determining the neutron dosage in step (e).

7. The method of claim 3 , wherein the first OSL sensor comprises a converter material disc located between the OSLM of the first OSL and a base of a first cylindrical cup-shaped filter of the first OSL sensor in which the OSLM of the first OSL sensor is mounted.

8. The method of claim 7 , wherein the converter material disc comprises high-density polyethylene and wherein there is a conformal disc comprising polyethylene located between the OSLM and the converter material disc.

9. The method of claim 7 , wherein the second OSL sensor comprises a reference filter material disc comprising polytetrafluoroethylene located between the OSLM of the second OSL sensor and a base of a first cylindrical cup-shaped filter of the second OSL sensor in which the OSLM of the second OSL sensor is mounted.

10. The method of claim 9 , wherein the first cylindrical cup-shaped filter for first OSL sensor and the second OSL sensor are each mounted in a respective second cylindrical cup-shaped filter and wherein the respective first cylindrical cup-shaped filters of the first OSL sensor and the second OSL sensor are substantially identical to each other.

11. The method of claim 3 , wherein the two or more sensors comprise a third OSL sensor, wherein the third OSL sensor is a comparator OSL sensor for the second OSL sensor, wherein a third radiation dosage of x-ray and gamma ray radiation for the dosimeter is measured from the third OSL sensor, and wherein the method of claim 5 further comprises the following step:

(e) determining the x-ray and gamma ray radiation dosage to which the dosimeter has been exposed based on the second radiation dosage and the third radiation dosage.

12. The method of claim 11 , further comprising the following step:

(f) reading an RFID tag that is part of the dosimeter sled to obtain information that may be used in determining the x-ray and gamma ray radiation dosage in step (e),

wherein the x-ray and gamma ray radiation dosage determined in step (e) is based on the information obtained from the RFID tag in step (f).

13. The method of claim 11 , further comprising the following step:

(f) determining the amount of stimulation light used in conducting step (a),

wherein the x-ray and gamma ray radiation dosage determined in (e) is based on the amount of stimulation light determined in step (f).

14. The method of claim 11 , further comprising the following step:

(f) determining the amount of non-radiation induced light received by the OSL reader conducting step (b) for use in determining the x-ray and gamma ray radiation dosage in step (e).

15. The method of claim 11 , wherein the third OSL sensor comprises a reference filter material disc comprising polytetrafluoroethylene located between the OSLM of the third OSL sensor and a base of a first cylindrical cup-shaped filter of the third OSL sensor in which the OSLM of the third OSL sensor is mounted.

16. The method of claim 1 , wherein step (b) comprises stimulating the OSLM of the selected OSL sensor with pulses of stimulation light of varying duration.

17. The method of claim 1 , wherein step (b) comprising stimulating the OSLM of the selected OSL sensor with pulses of stimulation light of varying frequency.

18. The method of claim 1 , further comprising the following steps:

(d) measuring a luminescence intensity of the selected OSL sensor; and

(e) selecting a pulsed optically stimulated luminescence (POSL) process based on the luminescence intensity measured in step (d).

19. The method of claim 18 , wherein step (d) is conducted for less than about 10% of the time that step (b) is conducted for each of the two or more OSL sensors.

20. The method of claim 1 , wherein the OSLM comprises an Al 2 O 3 :C material.

21. The method of claim 20 , wherein the Al 2 O 3 :C material has a grain size of 30 to 40 μm.

22. The method of claim 1 , wherein each OSL sensor of the two or more OSL sensors has an exposed side on a first face of the dosimeter sled and a filtered side on a second face of the dosimeter sled.

23. The method of claim 1 , further comprising the following step:

(d) pulling out the dosimeter sled from a recess in a housing of the dosimeter in which the dosimeter sled is mounted prior to step (a).

24. A method comprising the following steps:

(a) moving an optically stimulated luminescence (OSL) sensor of two or more OSL sensors mounted on a dosimeter sled to a reading position for an OSL reader; and

(b) reading the OSL sensor at the reading position using the OSL reader to measure a radiation dosage to which a dosimeter in which the dosimeter sled has been mounted has been exposed,

wherein the OSL sensor comprises an optically stimulated luminescent material (OSLM) mounted in one or more cylindrical cup-shaped energy compensating filters.

Assignments (6)
RELEASE OF SECURITY INTEREST Recorded Nov 6, 2017
From: BMO HARRIS BANK N.A
To: LANDAUER, INC
Reel/Frame 044368/0295 →
SECURITY INTEREST Recorded Jul 14, 2017
From: LANDAUER, INC.
To: BMO HARRIS BANK N.A.
Reel/Frame 043010/0956 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 18, 2013
From: YODER, R. CRAIG; AKSELROD, MARK S.; TATSUMI, YOSHIKAZU; LO, TSE-MIN
To: LANDAUER, INC.
Reel/Frame 030243/0170 →
CORRECTIVE ASSIGNMENT TO CORRECT THE NAME OF THE ASSIGNEE FROM LAND TO LANDAUER, INC. PREVIOUSLY RECORDED ON REEL 024508 FRAME 0018. ASSIGNOR(S) HEREBY CONFIRMS THE ASSIGNEE SHOULD BE LISTED AS LANDAUER, INC.. Recorded Feb 21, 2013
From: YODER, R CRAIG; AKSELROD, MARK S.
To: LANDAUER, INC.
Reel/Frame 029847/0920 →
SECURITY AGREEMENT Recorded Dec 1, 2011
From: LANDAUER, INC.
To: BMO HARRIS BANK N.A.
Reel/Frame 027308/0379 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 9, 2010
From: YODER, R. CRAIG; AKSELROD, MARK S.
To: LAND
Reel/Frame 024508/0018 →
Continuity (2)
Provisional Application 61294142 · Jan 12, 2010
Related Publication 20110168772A1 · Jul 14, 2011