OPTICAL SYSTEM FOR DOSIMETER READER

• US 20110168912A1
• Filed: 04/09/2010
• Published: 07/14/2011
• Est. Priority Date: 01/12/2010
• Status: Active Grant

• Current Assignee: Landauer, Inc. (Fortive Corp.)
• Original Assignee: Landauer, Inc. (Fortive Corp.)
• Inventors: Akselrod, Mark S., YODER, R. Craig
• Granted Patent: US 8,633,455 B2
• Time in Patent Office: Days
• US Class Current: 250/458.1
• CPC Class Codes: G01T 1/105 Read-out devices G01T1/115 takes precedence
• CPC Class Codes: G01T 3/00 Measuring neutron radiation G01T5/00 takes precedence

Abstract

Described is an optical system for a dosimeter reader having reduced sensitivity to vibration and motion.

Claims

1. A device comprising:

an optically stimulated luminescence (OSL) reader for reading an OSL sensor positioned above an optical light pipe of the OSL reader,

wherein the OSL reader comprises;

a light source emitting stimulation light for stimulating an optically stimulated luminescent material (OSLM) of the OSL sensor; and

the optical light pipe for uniformly illuminating the OSL sensor with the stimulation light,

wherein the stimulation light defines a first light path, and

wherein the optical light pipe is located on a first light path between the light source and the reading position for the OSL reader.

2. The device of claim 1, wherein the light source comprises a light emitting diode (LED).

3. The device of claim 1, wherein the OSL reader comprises an emitted light detector for detecting luminescence light emitted by the OSL sensor after the OSL sensor is illuminated with the stimulation light.

4. The device of claim 3, wherein the emitted light detector is part of a photomultiplier tube.

5. The device of claim 3, wherein the OSL reader comprises a dichroic mirror that allows the stimulation light to pass therethrough and that reflects luminescence light emitted by the OSL sensor towards the emitted light detector and wherein the dichroic mirror is located on the first light path between the light source and the optical light pipe.

6. The device of claim 5, wherein the OSL reader comprises a green filter for filtering out non-green light in the stimulation light and wherein the green filter is located on the first light path between the light source and the optical light pipe.

7. The device of claim 6, wherein the green filter comprises a green glass filter and wherein the green glass filter and the dichroic filter are part of a filter optic assembly mounted in an opening of a photo-optical engine frame of the OSL reader so that the filter optic assembly does not substantially move or vibrate when the OSL reader is moved or vibrated.

8. The device of claim 6, wherein the device comprises a blue filter for filtering out non-blue light from the emitted luminescence light and for filtering out any stray light or stimulation light that not removed by the green filter, wherein the emitted luminescence light defines a second light path and wherein the blue filter is located on the second light path between the dichroic mirror and the emitted light detector.

9. The device of claim 8, wherein the first light path and the second light path do not substantially move or vibrate when the OSL reader is moved or vibrated.

10. The device of claim 8, wherein the OSL reader comprises an activity sensor for determining that the OSL reader is functional when a non-zero (non-0) reading is received by the activity sensor due to a portion of stimulated light being reflected by the dichroic mirror.

11. The device of claim 1, wherein the OSLM of the OSL sensor is approximately 1 mm from the exit of the optical light pipe.

12. The device of claim 1, wherein the OSL reader comprises a dichroic mirror and an activity sensor for determining that the OSL reader is functional when a non-zero (non-0) reading is received by the activity sensor due to a portion of stimulated light being reflected by the dichroic mirror.

13. The device of claim 12, wherein the activity sensor comprises a photodiode.

14. The device of claim 1, wherein each of the OSL sensor comprises an optically stimulated luminescent material (OSLM) mounted in one or more in one or more cylindrical cup-shaped energy compensating filters.

15. The device of claim 14, wherein the OSLM comprises an Al₂O₃:

C material.

16. The device of claim 1, wherein the stimulation light source is an LED.

17. The device of claim 1, wherein the stimulation light source transmits stimulation light having a wavelength of about 520 nm and wherein OSL sensor emits luminescence light at a wavelength of about 420 nm in response to the OSL sensor being illuminated with the stimulation light.

18. The device of claim 1, wherein the OSL reader can read the OSL sensor while the OSL reader is being moved.

19. A device comprising a filter optic assembly comprising the following components:

an assembly mount bottom;

an assembly mount top;

an optical filter for filtering out lights of selected wavelength; and

a dichroic mirror aligned with the optical filter,

wherein the assembly mount bottom and assembly mount top together enclose the optical filter and dichroic mirror,

wherein the optical filter passes stimulation light having a wavelength that will stimulate an optically stimulated luminescent material (OSLM), and

wherein the dichroic filter reflects light emitted by the OSLM when the OSLM is stimulated by the stimulation light.

20. The device of claim 19, wherein the device comprises:

a lower gasket sandwiched between the assembly mount bottom and the optical filter;

a middle gasket sandwiched between the optical filter and the dichroic mirror; and

an upper gasket sandwiched between the dichroic mirror and the assembly mount top,

wherein the lower gasket, middle gasket and upper gasket are each comprised of a resilient material and each include an opening through which light may pass.

21. The device of claim 20, wherein the filter optical assembly is held together by an interior wall of a photo-optical engine frame in which the filter optical assembly is mounted.

22. The device of claim 21, wherein the device comprises the photo-optical engine frame.

23. The device of claim 22, wherein the device comprises a light source mounted on the photo-optical engine frame, wherein the light source emits the stimulation light, and wherein the stimulation light defines a light path through the filter optical assembly.