Optical Position Sensor: - PowerPoint Presentation

Slide1

Optical Position Sensor: Radiation Hard glasses for lenses and new electronics

Jose Luis Sirvent Blasco

Student meeting

26-11-2012Slide2

1. Issues due to radiationA) Lenses goes dark as they are irradiated

Reduce the life time of the system

Possibility of unavailability of this important subsystem.

Decrease of the transparency:Irradiation conditionsWavelength usedGlass materialRecovery (Annealing)TimeTemperature

*3rd

Europa Jupiter System Mission Instrument Workshop, ESA ESTEC January 2010, D. Doyle, ESTEC, Optical Materials

8KGy (8 years of WS operation 1KGy year) Slide3

1. Issues due to radiation

B) In general:

Decrease of transparency in NIR & IR is not as strong as in VIS or UV

Dopants such as Cerium in the glasses stabilizes Radiation effectsNumerous studies of radiation damage in glasses (literature)*Best ‘standard’ materials: Fused Silica, Sapphire & Quartz (Very Expensive)

Quite few elements available in the market for our designOther Solutions: RadHard

Glases (Schott & Ohara)No commercial lenses availables with this RadHard materials (lens done under demand)Need of lens design with my friend Zemax.

* A study of neutron and gamma radiation effects on transmission of various types of glasses, optical coatings, cemented optics and fiber.

S.M

.

Javed

Akhtar

*, Mohammad Ashraf, Shaukat Hameed Khan Optics Laboratories,Islamabad, Pakistan. 22 September 2006

2.4KGy (2 years)Slide4

2. Irradiated glass comparisonSlide5

3. What happens with the lens of our design for the WS_OPS? Materials:

Corning Eco-550 (

Asphere

Thorlabs 352440)Corning Co-550 (Aspheres Schaffter+Kirchhoff) No reports about radiation damage! (I cannot quantify the damage in our environment for the moment).

Previous Studies:Optical Design Considerations for Astronomical and Space Applications

Simon Thibault (2002 INO, Sainte-Foy, Québec, Canada):“Standard component for ground communication system as collimator can not be used for space application because it may happen that the glass material will be sensitive to radiation. By example, the molded Corning glass CO550 used for aspherical lens is sensitive to radiation

. Corning has developed a stabilized CO550-G20 with 2%of CeO2 with a greater radiation stability.”

“

The

coupling

efficiencies have to remain high once the system is in space, i.e. in vacuum and at a temperature ranging from 25 to 55 °C. For this space applications, we used only a single glass type which is the stabilized BK7-G18 from Schott”Optical system design and integration of the Mercury Laser Altimeter (L. Ramos-Izquierdo 2004 MESSENGER mission to mercury)

“The collimating lenses are 11mm focal-length Geltech aspheres with

2% cerium added to the Corning C0550

substrate material to prevent

adiation

darkening

”

“The beam expander is a Galilean optical design with a

Corning 7980 fused-silica

negative lens, a

BK7G18

positive lens group, and a

Sapphire

exit window.”

Radiation Hardness study on fused silica (M.

Hoek

, Ed.

Bennet

,

D.Branford

Nuclear instr. And Methods in Physics Research 2008)

“

Normalised

transmission difference

DTnorm

for (a)

Corning 7980

and (b)

Lithosil

Q0

for 1 and 10

Mrad

dose spots

. No distinct features corresponding to the irradiation spots are observed

within the obtained precision.

“Slide6

4. After reading:Conclusion about best materials:

Corning CO550-G20

 Aspheric lens provider:

LightPath “We cannot supply a specialty glass for only 3 lenses.  I am not sure about the possibility of 60 lenses either since I don't know the level of effort involved but I will ask.”  (John Luvera, LightPath)

Schott BK7-G18  Needed to fabricate lens: Optimax

Systems “We do have experience with RadHard materials and have worked quite a bit with space applications. Most recent being the Mars Curiosity for NASA JPL. We fabricated the lenses for the MARDI, MAHLI, and Mast Cameras aboard Curiosity. Send us the characteritics of your lens and we’ll quote.” (Jess Dennie, Optimax)Corning C79-80 / Schott Suprasil, Lithosil (F_Silica)

 “Standard” “Search in Edmund-Optics/Thorlabs/Newport/Asphericon/

Melles

Griot

& many other companies”

Sapphire

 Quite expensiveSpectral Transmission of Schott Lithosil Q0/1 F_Silica

Near our working wavelength 1310nmSlide7

5. Design criteria1. Magnification Factor=2 

Ligh

spot 20um

Measurable slits 5um (-6dB), 10 um (-3dB), 20um (0dB)2. Tolerance Disk/Lens  ~ 150um3. System Diameter Compact system (12mm optics)

4. System Length  As short as possible

5. Usage of ZemaxPhysical Optics Propagation  Gauss beam Waist = 0.0046um (SMF output 1310nm)Optimization tool to adapt parameters to our criteria and maximize coupling eff.Slide8

Prop 1Commercial Asphericon

C7980/

Lithosil

Q1 F_Silica2 X A12-15FPXTwo Identical lenses F=15mmCoupling=70% , Decrease in 100um=30%Slide9

Prop 2Commercial Asphericon

C7980/

Lithosil

Q1 F_Silica1 X A12-15FPX1 X A12-20FPXTwo different lenses F=15mm & F=20mmCoupling=72% , Decrease in 100um=20%Slide10

Prop 3Custom lens designed with Zemax

and BK7-G18 (Schott

RadHard

Glass)Only one Bi-Aspheric Lens (Mag. Factor=2 2*F1=F2)Minimize Aberrations and maximize coupling effShould fit in Holder (Optics 12mm and Thickness <=10mm)Coupling= 78%, Decrease in 100um= 20%Slide11

Prop 3Custom lens designed with Zemax

and BK7-G18 (Schott

RadHard

Glass)Only one Bi-Aspheric Lens (Mag. Factor=2 2*F1=F2)Minimize Aberrations and maximize coupling effShould fit in Holder (Optics 12mm and Thickness <=10mm)Coupling= 78%, Decrease in 100um= 20%

To give you a rough I idea on cost for a bi-

asphere at quantity 6:-Commercial Quality ($900 each)

-Precision ($2000 each)-Hi Precision

($3600 each)

(

Optimax

Systems mail Jess

Dennie

28-12-12)Slide12

Prop 4Commercial Edmund Optics Aspheric Lens

F_Silica

1x NT49-593

1x NT67-280Two Aspheres 0.5NA & 0.63NA (25mm Diam)Coupling= 71%, Decrease in 100um < 20%In my opinion it’s maybe too bigSlide13

6. RemarksProp 1 & 2 Selected as the best ones

Material already ordered

Physical test to be done

 Vacuum & TemperatureAssembly materials  Aluminum & Co7980The Optics will also be tested in the TestBench and compared with Schaffter+Kirrchoff

(CO550) Some electronics should be developed and fitted in a “Nice Box 2.0”

Laser driver with digital power control (Voltage controlled current source DAC 0-1V)Photodiode driver for ADC 0-1V (PD Signal  Offset 4V & 0.8Vpp, Differential to Single ended signal + Gain control) Optical circulator included in “The Box”

The current Box

(Face A:

1Ch

850nm, Face B: 2Ch 1310nm, Face C: Driver for

Heidenhain

Ron225)

On

Off

LD Power

F.Optic

I/O

LD Power ADC

PD DAC

The New and final box

(Only one face two channels 1310nm & prepared for DAC & ADC)Slide14

7. Drivers for DAC & ADCSlide15

7.1 Driver for DAC (Limited current source for LD)Slide16

7.2 Driver for ADC (First Tests with AD 8608)AD 8608

 I/O Rail to Rail 5V, 10MHz

High Impedance buffers

Differential ampliffier (G=1)Non Inverting ampliffier (G  1 – 5)

Final Op_Amp_ AD 8028 (190MHz)