Fiber Optic TOAD (Time of Arrival Diagnostic) shock break out validation using PDV

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Title: Fiber Optic

TOAD

(

T

ime

O

f

A

rrival

D

iagnostic) shock

break out validation using PDV.

PDV Workshop 2014 Hosted by:

National Security Technologies, LLC and the

University of Nevada Las Vegas

Dates: June 24-26

(Las Vegas, Nevada, United States)

Author(s): Shinas Michael A., LANL, WX-4: DARHT EXPERIMENTS AND DIAGNOSTICS

Briggs Matthew E., LANL, WX-4: DARHT EXPERIMENTS AND DIAGNOSTICS

Hare Steven J., LANL, WX-4: DARHT EXPERIMENTS AND DIAGNOSTICS

Archuleta Michael A., LANL, WX-3: FOCUSED EXPERIMENTS

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Made with off the shelf components.

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Eye safe.

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The Fiber Optical TOAD probe, needs to be low cost

and have high precision.

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The Fiber Optic TOAD needs to measure the

detonation wave arrival time on explosive

experiments.

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Validate that Fiber Optic TOAD arrival time is correct,

with a second diagnostic.(PDV)

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Easy to field.

I was asked to developing a new type Fiber

Optical

TOAD

(

T

ime

O

f

A

rrival

D

iagnostic).

Slide 2

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Description of the Fiber Optic TOAD.

Slide 3

Bi-directional

Fiber optic coupler

Detector

HE

Oscilloscope

Aluminum coating

CW Laser

Transition when the aluminum

coating goes away.

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Experimental set up to test and validate

the Fiber Optic TOAD measurement.

Slide 4

1550 nm Laser 90%10% 1GHZ freq. shift Circulator 90% 10% Optical attenuator PDV detector 1060 Ångström of Aluminum Optical attenuator 90% 10% SE-1 1/2" x 1/2" booster 2 W .225 W .2 W .02 W Oscope # 1 CH1 CH2 1 x 8 Oscope # 2 CH1 CH2

note: -20dbm was coming from the Al coating before we added the unshifted to give us 0dbm.

I adjusted the! Optical attenuator! to get 3 dbm onto! the detector MITEQ model # DR-125G-A detector

1

₂

3

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Experimental package for bare HE shot

and fiber optic TOAD probe.

Slide 5

½ “ x ½ “ 9407 pellet

St. connector taken apart,

just leaves a 2.5mm ferrule

The fiber is centered in the

middle of the ferrule to ≤ 1µm.

The outer diameter tolerance

Is ± 0.5 µm.

A 1550nm single mode

jumper cost about $12.

1060A° of Aluminum is coating

the end of a 9µm core.

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Fiber Optic TOAD Data, bare HE shot.

170 ps

8.856 ns

Note:

A 12.5Ghz detector can

see a 80 ps event, the

oscilloscope was set to

50Gs/s so the scope

was taking a sample

every 20 ps.

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PDV data bare HE shot

Window size 1.28ns

Window steps 160ps

Raw data

ROI

Jump up to

≈ 2.6 km/s

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90%

10%

1GHZ freq. shift

Circulator

90%

10%

Optical attenuator

PDV

detector

Optical attenuator

90%

10%

2 W

.225 W

.2 W

.02 W

Oscope # 1

CH1 CH2

1 x 8

MITEQ model #

DR-125G-A

detector

1

₂

3

30 ps

pulsed

laser

1550 nm

Laser

Timing correction between the Fiber

optic TOAD signal and the PDV record.

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TOAD measured arrival time vs. PDV, with

time corrections applied.

Slide 9

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TOAD vs. PDV raw data.

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.010 inch Stainless steel Shim disks was

glued to booster pellet.

Slide 11

McMaster-Carr part # 2895T51

Type 302/304 Stainless Steel

Shim Disc 1/2" Diameter,

.01" Thick

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PDV Data with .010” shim stock

Slide 12

Jump up to

≈ 1.4 km/s

Window size 1.28ns

Window steps 160ps

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Fiber Optic TOAD Data with .010” shim

stock

Slide 13

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TOAD shock arrival time vs. PDV start of

motion.

Slide 14

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Sweeping wave shot on bare HE.

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PDV sweeping wave results.

Slide 16

≈ 1.5 km/s

Window size 1.28ns

Window steps 160ps

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Fiber Optic TOAD sweeping wave arrival

time.

Slide 17

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PDV start of motion vs. the Fiber Optic

TOAD shock arrival time.

Slide 18

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640nm Fiber optic TOAD system.

Slide 19

sensitivity of APD = 18,000V/W @ 641nm 1 X 4 5m APD #1 1 X 4 2 x 2 2 x 2 2 x 2 2 x 2 2 x 2 2 x 2 2 x 2 2 x 2 1 X 4 1 X 4 1 X 4 2 x 2 2 x 2 2 x 2 2 x 2 2 x 2 2 x 2 2 x 2 2 x 2 APD

#2 APD #3 #4APD APD #5 #6APD #7APD APD #8 #9APD APD #10APD #11APD #12APD #13APD #14APD #15APD #16

30m 1m 1m 1m 1m 1m 1m 2m 1m in in in in in in in in in in in in in in in in Laser Optical isolator

Lens coupled into a 4 µm single mode fiber

60mW

OZ Optics 120mW, 641nm Frabry Perot laser diode

Oscilloscope #1 Oscilloscope #2 Oscilloscope #3 Oscilloscope #4 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Fiber optic pin with 1000 A of Aluminum

.434mW

.073mW

- 1.3 V

Drawing name: Fiber optic pin light source distribution chassis. 06/23/2013 Engineer: Michael A. Shinas, LANL, WX-4

Class 1

Laser

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Portable 16 channel TOAD system.

Slide 20

light source

distribution and

return light chassis

Oz Optics

60 mW laser

NSTec APD

DC-500 Mega Hz

Before the shot it’s

very easy to check

if the fiber optic pins

are working.

To save room, one

rack can be stack

on the top of the other.

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Data from the new 640nm TOAD system.

Slide 21

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Summary

Slide 22

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The PDV, proved experimental that the disappearance of the light

reflected from the aluminum coating corresponds to the arrival of the

detonation wave front.

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Demonstrated that the Fiber Optic TOAD will give a time of arrival

normal to the HE or as the wave sweeps across the fiber optic pin.

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A Fiber Optic TOAD can measure the arrival of a shock wave through

a .010” thick SS shim.

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Designed and build a Class 1 laser portable 16 channel Fiber Optic

TOAD system.

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The active area of the fiber optic is very small only 4.3µm and the

outer diameter tolerance is ± 0.5 µm. This will giving you a shock

break out time at a very exact location.