TRIDENT direct-drive materials shots
"Polar Bearyllium"
Dec 2003 - Jan 2004

Contents

• Objectives
• Schedule and statistics
• Sample materials
• Targets
• Drive conditions
• Diagnostics
• Alignment
• Shot summary
• Notable events
• Experimental observations
• Evaluation
• Acknowledgements

Objectives

• Beryllium properties for ICF
• NIF Materials IET
• "SPAM" LDRD

Primary objectives:

1. Determine shock melt conditions for Be using VISAR and ellipsometry. 20% successful.
2. Investigate strength and phase changes in shock-loaded Ti, V, Ta, and/or Fe. 80% successful.
3. Perform shock/recovery experiments on NiAl samples with VISAR and TXD. 75% successful.
4. Perform TXD and pyrometry development for subsequent TRIDENT campaigns. 60% successful.
5. Obtain data relating to the dynamics of melting. 50% successful.

Specific tasks:

1. Direct drive expts on Be to melt (VISAR / ellipsometry, LiF window) + supporting experiments. 100% successful.
2. Shock/recovery expts on NiAl single crystals, bicrystals, with line VISAR, TXD. 75% successful.
3. TXD of melt, e.g. Ga / Sn. 50% successful.
4. VISAR/TXD/ellipsometry of Ti, V (+ possibly Ta, Fe). 80% successful.
5. Test of quadrature line VISAR. 80% successful.
6. Pyrometry development. 80% successful.
7. Test of x-ray yields using C beam. Cancelled.
8. Trials of sample preheater/precooler. 100% successful.
9. Test of x-ray radiography in 1D drive expt. Cancelled.
10. Test of x-ray streak cameras with CCD recording. 100% successful.

Opportunistic:

1. Obtain additional Sn VISAR/ellipsometry data. 80% successful.
2. Obtain trial Fe VISAR/ellipsometry data. 80% successful.
3. Shock and recover stishovite. 10% successful.
4. Shock and recover MgB₂. 50% successful.
5. Shock and recover Bi. 10% successful.

Success ratings are based on what we expected to achieve during the session, not on all that could possibly be done. A "successful trial" does not mean that the technique under trial necessarily worked.

Schedule and statistics

• Plan refers to TRIDENT schedule ~Oct 2003.
• The extra week was brought forward (given the opportunity by the postponement of the "gas jet" experiment) because we were reasonably well set up and operational, with more experiments useful with the same configuration.
• We were able to remove equipment gradually during the maintenance time following these experiments. This was very helpful.

Shot allocations
	Plan	Actual	Comments
W	~15	22	Trident and pyrometry problems: repeated some shots.
Be	~8	9
Fe	-	4	Ellipsometry / VISAR to complete paper.
Sn	-	4	Ellipsometry / VISAR to complete paper.
Melt TXD (Ga)	~8	4	Problems with preshot characterization: IWD-related delays.
V TXD	~10	5	Extra time needed to set up new configuration and debug diagnostics.
Si TXD		2	Used to test NIF IET configuration.
Ti TXD	~10	8
NiAl	~8	10	Used some brought-forward time.
stishovite and MgB2 recovery	"a few"	3	Possible high-profile papers.
Bi	-	2	Tests of LLNL-design hot stage.
Total	~48	75

Use of time
Date	Activity	Comments
8 Dec	setup: B beam pointing + timing
9 Dec	setup: A beam pointing + timing
10 Dec	shots: W VISAR + ellips
11 Dec	setup: hot/cold stage + beam profiler	Bi shot
12 Dec	TRIDENT maintenance
15 Dec	shots: W VISAR + ellips; setup: IET TXD
16 Dec	shots: IET V TXD
17 Dec	shots: IET Ti TXD
18 Dec	shots: IET Ti TXD
19 Dec	TRIDENT maintenance
22 Dec	TRIDENT maintenance
23 Dec	TRIDENT maintenance
2 Jan	lab closed
5 Jan	shots: W VISAR + ellips	no energy readings
6 Jan	shots: W+Be VISAR + ellips	no energies a.m.
7 Jan	shots: Be+Fe VISAR + ellips, stishovite recovery
8 Jan	shots: Fe,Be,Sn VISAR + ellips
9 Jan	setup: x-ray streaks
12 Jan	shot: Ga TXD	tgt pos + amp problems
13 Jan	shots: Ga,NiAl TXD; Bi VISAR
14 Jan	shots: Ga,NiAl TXD
15 Jan	shots: NiAl TXD	laser problems
16 Jan	shots: Ga,NiAl TXD

Firing duration and rate
	Expected	Actual	Comments
Setup (days)	4.0	4.5
Experiments (days)	8.0	12.0
Rate (shots/day)	6.0	6.2

Notes:

• "Setup" time here is facility time used for setup. It ignores time spent while other experiments were in progress, and out-of-hours time.

Sample materials

Targets

Figure 1: Archuleta (VISAR) holder

Figure 2: Ortiz (TXD) holder

Figure 3: Lorenzana (wide-angle TXD) holder

We also tried out Bryan Reed's heated and cooled holder, in which the sample was held in place by set screws. The target was in contact with a ring of Cu tubing through which coolant (water) was fed post-shot to quench the recovered sample and preserve features in the microstructure. The cooling tube was purged with nitrogen before heating. Heating was provided by a halogen lamp in a tungsten foil furnace, focused onto the target with a fast lens and mounted on a versatile bracket. Temperatures were monitored by thermocouples in the ring The cooling ring was also held in place by the force of the set screws, and target changing was awkward because of torque from the coolant tubes when working in the confined and crowded space of the chamber. The heating lamp also proved troublesome: it needed to be quite close to the sample for efficient energy coupling, but it was difficult to find a suitable position without having to remove VISAR/ellipsometry optics (not possible on this occasion), and the mounting bracket proved to be somewhat too flexible with restricted chamber access.

Figure 4: Reed (heated/cooled) holder

Figure 5: Reed (heated/cooled) holder with heating lamp in operation

Drive conditions

Experiments were fired with different sizes of focal spot to give different ranges of pressure in the sample. Diffractive optical elements were used where possible to smooth large-scale spatial variations in beam intensity. Generally these phase plates were not ideal for the desired uniformity or spot size, so the drive beam was defocused slightly.

Diagnostics

The optical layout used was based on the standard VISAR layout, with the spectrometry signal taken from the VISAR output beam path outside the vacuum chamber, making it a very convenient addition. For the first time, ellipsometry was performed simultaneously with VISAR, with incoming and outgoing beam paths to either side of the VISAR path near the target. A prototype quadrature was included, with data recorded on the camera otherwise used for ellipsometry. VISAR and TXD orientations were chosen based on early assumptions about IET experiments requiring both; in the event it was not possible to field VISAR on the IET TXD shots because of orientation constraints imposed by the wide-angle TXD holder.

Figure 6: Experimental layout for VISAR/spectrometry/ellipsometry shots (block diagram).

Figure 7: Experimental layout for VISAR/quadrature VISAR/spectrometry shots (block diagram).

Figure 8: Experimental layout for wide-angle TXD shots (block diagram).

Figure 9: Experimental layout for VISAR/spectrometry/TXD shots (block diagram).

Line VISAR

There was generally plenty of probe laser light. For NiAl shots, an OD of 2.0 was used; for Ga shots, an OD of 0.4; for polished W, an OD of 1.7.

The camera slits were set to approximately 300 µm.

An in situ alignment system was set up, comprising CCD cameras focused onto the output beamsplitter and at an equivalent focal plane of the streak camera. The pattern of speckes reflected from the sample surface could then be imaged continuously while adjusting the VISAR alignment: much more convenient then waiting for streak camera frames or juggling white cards.

Fringe constant

Timing relative to drive beam

The timing of the streak record relative to the drive beam was established by omitting the target and capturing light from the drive beam (in 5 Hz timing mode) down the VISAR optics to the camera. The camera delay was then adjusted until the drive pulse was visible close to the center of the record. The probe laser delay was then adjusted so the pulse appeared in the record (using a reflective target).

VISAR streak camera delays
sweep period	delay
(ns)	(ns)
50	2825
20	2880
10	2894
5	2906

Delays are for element 13 of B-beam to be nominally at center of record. The Q-switch channel delay was 2620 ns except when changed to account for very long shock transit times, as noted in the shot log.

Fiducial markers

Line VISAR with quadrature

Emission spectroscopy

The spectrometer signal was recorded on a Hamamatsu streak camera. For a 50 ns sweep, the triggering delay necessary for the drive pulse to be at the center of the time window was 2778.5 ns.

For emission spectrometry, a grating of 100 lines/mm was used, centered on a wavelength of 700 nm and with a spectral resolution of 1.92 nm.

Some 660 nm light did propagate down the optical path for the spectroscopy. This acted as both a wavelength calibration and allowed for the possibility of Raman spectroscopy on every shot. On occasion, scatter from the 527 nm drive laser was weakly visible on the streak record.

Ellipsometry

Ellipsometry streak camera delays
sweep period	delay	notes
(ns)	(ns)
50	2831	A-beam at center
20	2887	1st fidu pulse at center
10	2896	1st fidu pulse at center

A-beam refers to element 13 of the pulse. To relate A and B beams, A was retro-reflected down the VISAR optics, and was (roughly) centered for a VISAR camera delay of 2987 ns. The precise timing was found from the relation of the pulse to the timing fiducial markers: file atim1209.ipl on the VISAR camera.

The objective of ellipsometry was to detect shock/release melting in samples of Be and Sn. A release window was necessary to maintain pressure when the shock reached the surface. LiF was chosen, as previous experience with flyer impact and isentropic compression experiments at Z had shown that it remained transparent at pressures over 200 GPa for longer times than needed in these experiments. However, it was necessary to discriminate between the effect of the LiF and the sample, so calibration experiments were performed using W samples which were expected to remain solid to shock pressures greater than for Be or Sn.

Transient x-ray diffraction

The X-ray source was helium-alpha radiation from a plasma generated with the "A" beam, focused to as small a spot as possible on a foil ~10 µm thick. Ti or Mn foils were used (wavelengths 2.61 and 2.006 Å respectively), chosen according to the lattice spacing of the sample.

X-rays from the plasma were incident on the sample material, and diffracted according to the Bragg condition. A large part of the sample was illuminated and the Bragg return occured from a circular arc in the surface.

Two types of experiment were performed, with the x-ray source ~1 mm from the sample (NIF Materials IET shots) or ~15 mm from the sample (melt and NiAl LDRD shots). The x-ray source was operated at various different times with respect to the shock drive, by altering the length of a trombone. Initial timing experiments were performed in which the light from either beam (5 Hz timing signal) was directed into the VISAR optics and recorded on the streak camera. (The collecting angle of the VISAR was large enough to pick up the B - shock - beam directly by simply omitting a target.)

For the IET shots, x-rays were recorded over an octant of a sphere using two planar detectors. These comprised filtering layers and either DEF film or an image plate as the active element.

For the other shots, diffracted X-rays were recorded on Kentech X-ray streak cameras situated to the north and south sides of the target; the slit of each camera was horizontal. The sweep period of the Kentechs was set to 2.5 ns throughout. The image from the Kentech intensifiers was recorded on optical film; attempts were made to use the Retriever CCD cameras for the first time but more development work is needed. Static film packs (DEF film) were mounted in front of the slit in each camera. In some shots, a static image plate was placed vertically in front of one or other of the cameras.

The X-ray detectors were shielded from direct shine from the source by an attenuating layer. This was the standard Au truncated cone around the backlighter foil, except in the close-in IET shots where a section of a truncated cone of Pb foil was used.

The X-ray source was monitored with a spectrometer mounted with the "Tubby" film detector.

X-ray streak camera delays
S camera	N camera	Notes
(ns)	(ns)
3009.1	3007.0

Delays for A beam pulse (13 elements) to fit over full field of view.

Filtering comprised 125 µm Be, 37 µm Ti, the time-integrating DEF film, 10 µm Ni, and 25 µm Be, then an additional 250 µm Be in front of the S Kentech camera. From shot 16450, an additional 10 µm Ni was added in front of the film pack.

Wide area transient x-ray diffraction

The backlighter was mounted in a half-cylinder of stainless steel ~250 µm thick acting as a shield to prevent direct exposure of the detectors by the x-rays. TRIDENT's A beam was used to generate x-rays from the backlighter, incident from the W. The beam was steered and focused with the help of a telescope viewing through the final turning mirror to the W. The alignment beam was visible even through the coated optic. The green light was focused differently from the reddish image of the target, but we reasoned that for the diffuse light visible from the backlighter foil (off-normal by some 30^o, best focus was the smallest spot even when the telescope was set to focus the foil image in red. The spot size could then be verified by finding best focus in green and comparing with the (remembered) size of features in the image of the target. This procedure was reliable and fast.

For Ti backlighters and V crystal, suitable filtering was ~750 µm Be, 25 µm Ti, and 12.5 µm Cu.

Alignment

Alignment was verified periodically e.g. using a sharp point, cross-hairs, or an aluminized LiF window with scratches (or ablation holes from the probe laser).

Shot record

• Target stack listed from drive side.
• Drive energy measured by calorimetry, as usual where the beam enters the target area.
• Aluminised Si: Al layer ~1000 Å
• Sample recovered unless stated.

VISAR/pyrometer/ellipsometer configuration
shot	target	VISAR		ellipsometer		pyrometer		drive			Comments
		sweep	delay	sweep	delay	sweep	delay	spot dia	duration	energy
		(ns)	(ns)	(ns)	(ns)	(ns)	(ns)	(mm)	(ns)	(J)
10 Dec
16365	W 25 and 50 µm	50	2825	50	2831	50		5.0	2.5	56	Ellipsometry: no trigger. Sample recovered.
16366	W 25 and 50 µm	50	2825	50	2831	50		5.0	2.5	49	Ellipsometer triggered, pyrometer did not (disconnected cable). Sample recovered.
16367	W 25 µm	20	2884	50	2831	50		5.0	2.5	103	All triggered.
16368	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	103	Excellent VISAR. Sample recovered.
16369	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	169	Sample recovered (LiF cracked).
16370	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	226	Sample recovered (LiF cracked).
16371	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	1.7	244	Sample recovered (LiF cracked).
16372	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	1.0	203	Sample recovered (LiF cracked).
10 Dec
16375	glass ~1 mm, Al 4 µm, Bi 125 µm	50	2875	-	-	-	-	5.0	2.5	0.99	Wedge for low energy. Sample flew out of holder, spattered onto blast shield.
16376	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	23	Good VISAR. Pyrometry did not trigger. Sample recovered, LiF cracked.
16378	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	54	Scrappy VISAR (slightly mispointed). Pyrometry did not trigger. Sample recovered, LiF cracked.
16379	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	105	Scrappy VISAR. Pyrometry did not trigger. Sample recovered: LiF cracked.
16380	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	208	Scrappy VISAR. Pyrometry did not trigger. Sample recovered: LiF spalled.
16 Dec
16386	W 50 µm, LiF 2000 µm	50	2835	50	2850	50		5.0	2.5	222	Ellipsometry camera used for quadrature VISAR (1 channel). Fidus weak.
17 Dec
16391	MgB2 660 µm, LiF 2000 µm	50	2985	50	3010	50		5.0	2.0	76	Ellipsometry camera used for quadrature VISAR (~3 ns longer path than Forsman VISAR). Probe delay moved to 2780 ns. Shock breakout apparently earlier than start of camera frames.
18 Dec
16395	W 50 µm, LiF 2000 µm	50	2835	50	2850	50		5.0	2.0	138	Ellipsometry camera used for quadrature VISAR. Fidus weak. Notch filter omitted from Forsman VISAR: green light bands.
5 Jan
16404	W 50 µm, LiF 2000 µm	50	2835	50	2850	50		1.5	1.0	150?	elements 1-6, ellipsometer not aligned, no energy reading, pyro triggering problem
16406	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	1.0	150?	no energy reading, pyro triggering problem
16408	W 50 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	1.0	150?	VISAR misaligned so omitted, no energy reading, pyro triggering problem
6 Jan
16411	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	1.0	150?	no energy reading, pyro triggering problem, VISAR fringes not visible after breakout
16412	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	150?	no energy reading, pyro triggering problem
16413	W 50 µm	20	2884	50	2831	50		1.5	2.5	131	poss pyrometry signal
16414	W 25 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	155	poss pyrometry signal; scrappy VISAR
16415	Be 50 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	63	probe laser on pyrometry, multi-fringe shift on VISAR, ellipsometry signal dropped a lot on breakout
16416	Be 50 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	35	Delayed pyro by 30 ns (still looked early). VISAR: ~1 fringe; ellipsometry: fluctuations after breakout.
7 Jan
16418	Be 50 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	105	Pyro triggering was set wrong. Ellipsometry signal dropped off on breakout.
16419	Be 50 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	23	Pyro not used. Ellipsometry signal dropped off on breakout.
16420	Be 50 µm, LiF 2000 µm	20	2884	50	2831	50		1.5	2.5	36	Ellipsometry signal dropped off on breakout.
16421	Al 25 µm, stishovite 380 µm, Al/LiF 2000 µm	50	2856	50	2862	50		1.5	2.0	167	Probe laser delayed 30 ns to 2660 ns. Sample apparently shattered.
16422	Be 50 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	105	Ellipsometry signal dropped off on breakout.
16423	Be 50 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	47	Ellipsometry fluctuated rapidly after breakout.
16424	Fe 30 µm, LiF 2000 µm	20	2888	50	2831	50		5.0	2.5	54	Breakout close to start of record.
16425	Fe 30 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	136	Beautiful VISAR.
8 Jan
16427	Fe 30 µm, LiF 1000 µm	20	2884	50	2831	50		5.0	2.5	192	Beautiful VISAR. Ellipsometry: only one line/pol visible; little effect.
16428	Be 15 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	57	Poor VISAR (breakout evident but no usable fringe shift); ellipsometry OK (no decrease on breakout).
16429	Fe 30 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	239	Good VISAR. Ellipsometry: Fe reflection was saturated on one channel; other didn't show any strong effect.
16430	Be 30 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	66	Poor VISAR (breakout evident but no usable fringe shift); ellipsometry OK (no decrease on breakout).
16431	Sn 25 µm, LiF 2000 µm	20	2884	50	2831	50		5.0	2.5	113	Scrappy VISAR; effect on ellipsometry.
16432	Sn 25 µm	20	2884	50	2850	50		5.0	2.5	96	Quad VISAR to ellipsometry camera.
16433	Sn 25 µm	20	2884	50	2850	50		5.0	2.5	64	Quad VISAR to ellipsometry camera. Nice VISAR.
16434	Sn 25 µm and 50 µm	20	2884	50	2850	50		5.0	2.5	153	Quad VISAR to ellipsometry camera. VISAR: saw one side only, contrast poor after breakout, intensity dropped off quickly.
13 Jan
16446	glass ~1 mm, Al 4 µm, Bi 125 µm	50	2875	50	2890	-	-	5.0	2.5	1.07	Wedge for low energy. Quad VISAR to ellipsometry camera. (Set up as 16445 but wrong beam was blocked in front end.) Raw 2w energy = 28 J cf 26 J previously giving 0.99 J on tgt.

VISAR/TXD configuration
shot	target	Forsman VISAR		Quadrature VISAR		pyrometer		S x-ray streak	N x-ray streak	drive			backlighter				Comments
		sweep	delay	sweep	delay	sweep	delay	delay	delay	spot dia	duration	energy	material	angle	delay wrt drive	energy
		(ns)	(ns)	(ns)	(ns)	(ns)	(ns)	(ns)	(ns)	(mm)	(ns)	(J)		(deg)	(ns)	(J)
12 Jan
16441	Ga 77 µm	-	-	-	-	-	-	3011.5	3009.4	5.0	2.5	0	Ti	46	2.4	168	S TI: narrow strong lines. S TR: saturated. N: no signals.
13 Jan
16443	Ga 77 µm	-	-	-	-	-	-	3011.5	3009.4	5.0	2.5	0	Ti	46	2.4	166	S TI: narrow strong line. S TR: saturated. N: no signals.
16444	NiAl (110) 110 µm (#2)	-	-	-	-	-	-	3011.5	3009.4	5.0	2.5	0	Ti	46	2.4	203	S TI: wide strong line. S TR: saturated. N: no signals.
16447	Ga 60 µm	20	2900	50	2860	50	2778.5	3026.6	3024.5	5.0	2.5	25	Ti	46	17.5	135	Predic transit time 18.5 ns. Quad VISAR to ellipsometry camera. VISAR slightly late. S TI: couple of blotchy lines. S TR: high background, no obvious lines.
16448	NiAl (110) 94 µm (#5)	50	2845	50	2860	50	2778.5	3026.6	3024.5	5.0	2.5	71	Ti	46	17.5	178	Predic transit time 18.5 ns. Quad VISAR to ellipsometry camera. VISAR: nice elastic+plastic+release/spall. Quad VISAR: promising signal. S TI: 2 dark lines, maybe another weak line. S TR: 1-2 lines.
14 Jan
16450	NiAl (110) 102 µm (#7)	50	2845	50	2860	50	2778.5	3026.6	3024.5	5.0	2.5	30	Ti	46	17.5	171	Dot on sample down in chamber + facing backlighter. Quad VISAR to ellipsometry camera. VISAR: slight multimoding; clear elastic wave. Quad VISAR: reasonable. S TI: nothing. S TR: maybe faint signal.
16451	Ga 68 µm	50	2845	50	2860	50	2778.5	3028.6	3026.5	5.0	2.5	48	Ti	46	19.5	142	Quad VISAR to ellipsometry camera. Increased gain on S Kentech. Probe laser anti-melting block left in: no VISAR data. S TI: nothing. S TR: ~saturated.
16452	NiAl (110) 116 µm (#4)	50	2845	50	2860	50	2778.5	3028.6	3026.5	5.0	2.5	227	Ti	46	19.5	124	Dot on sample down in chamber + facing backlighter. Quad VISAR to ellipsometry camera. VISAR: drive reflections, but clear elastic, plastic, release/spall. Quad VISAR: drive reflections, no clear differentiation between channels. PCD: no x-ray signal. Tubby: no Ti line. S TI: nothing. S TR: almost saturated (suspect intensifier problem).
16453	Ga 66 µm	50	2845	50	2860	50	2778.5	3028.6	3026.5	5.0	2.5	58	Ti	46	19.5	156	Quad VISAR to ellipsometry camera. Switched N and S Kentech intensifiers. VISAR: lots of drive reflections, but noisy elastic + plastic waves. S TI: broad lines. S TR: broad lines (may be photocathode noise).
16454	NiAl (111) 114 µm (NiAl-111-04-3)	50	2845	50	2860	50	2778.5	3028.6	3026.5	5.0	2.5	231	Mn (?)	53	19.5	98	Dot on sample down in chamber + facing backlighter. Quad VISAR to ellipsometry camera. Probe laser: slight multi-moding. VISAR: drive reflections; clear elastic wave, low amplitude plastic. Quad VISAR: many reflections; possibly usable fringe data (noisy). S TI: nothing. S TR: broad lines (may be photocathode noise).
15 Jan
16456	Ga 66 µm	50	2845?	50	2860?	50	2778.5?	3028.6	3022.0?	5.0	2.5	62	Ti	44	17.4	165	Filtering: removed 25 µm Ti to leave to 6 mil Be, 12.7 µm Ti, 10 mil Be.
16457	Ga 67 µm	50	2845?	50	2860?	50	2778.5?	3028.6	3022.0?	5.0	2.5	26	Ti	44	17.4	170
16458	NiAl (111) 82 µm (NiAl-111-04-4)	50	2845	50	2860	50	2778.5	3024.1	3022.0	5.0	2.5	101	Mn	53	15	243
16459	NiAl (111) 88 µm (NiAl-111-04-7)	50	2845	50	2860	50	2778.5	3025.1	-	5.0	2.5	211	Mn	53	15	228	Great VISAR record. TXD nearly identical to previous shot... photocathode noise?
16460	NiAl (111) 88 µm (NiAl-111-04-11)	50	2845	50	2860	50	2778.5	3025.1	-	5.0	2.5	134	Ti	38	15	121	TXD shows pc noise, but has visible line that is different from Mn backlighter shots.
16 Jan
16462	Ga 68 µm	50	2845	50	2860	50	2778.5	3028.6	-	5.0	2.5	95	Ti	46	19.5	130	Probe laser flaky... failed to produce pulse on this shot.
16463	NiAl (111) 98 µm (NiAl-111-04-5)	50	2845	50	2860	50	2778.5	3026.6	-	5.0	2.5	233	Ti	38.5	17.5	132	Special Request shot by Aaron Koskelo. Great VISAR record, similar to shot 16459 with pull-back visible at e-p transition. Interesting Pyrometer signal--- Raman candidate?
16464	Ga 59 µm	50	2845	50	2860	50	2778.5	3026.6	-	5.0	2.5	147	Ti	46	17.5	152	PC noise, TI TXD decent.
16465	NiAl (111) 100 µm (GE)	50	2845	50	2860	50	2778.5	3027.6	-	5.0	2.5	221	Ti	38	18.5	125	Great VISAR. TI TXD good, some interesting lines on TR TXD.

• X-ray timing shots: 16435, 16436, 16437, 16438, 16440; Au disc.
• Unless stated, sample was aligned to VISAR axis.
• Backlighter angle is defined wrt sample normal. 41^o is equivalent to due west.

Wide-angle TXD configuration
shot	target	backlighter	A (backlighter) beam			B (drive) beam			tA-tB	Comments
		spot dia	duration	energy	spot dia	duration	energy	(ns)
		(mm)	(ns)	(J)	(mm)	(ns)	(J)
15 Dec
16381	Ti (0001) 40 µm	Ti 7 µm	~0.1	2.0	246	5.0	2.0	0	4.2	Film saturated, IPs probably saturated, probably hit steel shield.
16 Dec
16383	Si (111) 380 µm	Ti 7 µm	~0.1	2.0	119	5.0	2.0	0	4.2	No signals (film behind IP).
16384	Si (111) 380 µm	Ti 7 µm	~0.1	2.0	186	5.0	2.0	0	4.2	Broad line on film.
16385	Al/CH 5 µm, V (110) ~2000 µm	Ti 7 µm	~0.1	2.0	195	5.0	2.0	0	4.2	Line on film, quite high background.
17 Dec
16388	Al/CH 5 µm, V (110) ~2000 µm	Ti 7 µm	~0.1	2.0	122	5.0	2.0	39	0.75	Broad line on film, PCD signal finally.
16389	Al/CH 5 µm, V (110) ~2000 µm	Ti 7 µm	~0.1	2.0	147	5.0	2.0	88	0.75	Lines on both films.
16390	Al/CH 5 µm, V (110) ~2000 µm	Ti 7 µm	~0.1	2.0	128	5.0	2.0	138	0.75	Weak lines.
16392	Al/CH 5 µm, V (110) ~2000 µm	Ti 7 µm	~0.1	2.0	146	5.0	2.0	0	0.75	Fairly weak lines, quite broad - sample surface (rough)?
16393	Al/CH 19 µm, Ti (0002) 40 µm	Ti 7 µm	~0.1	2.0	157	5.0	2.0	0	0.75	Strong lines, quite broad, triplet evident.
18 Dec
16396	Al/CH 19 µm, Ti (0002) 40 µm	Ti 7 µm	~0.1	2.0	154	5.0	2.0	15	2.4	X-ray filtering changed to 50 µm Ti.
16397	Al/CH 19 µm, Ti (0002) 40 µm	Ti 7 µm	~0.1	2.0	126	5.0	2.0	21	2.4	ST-V IPs in 25 µm Al around chamber: no signal recorded but PCD and film good (shocked line weak/blurred) so maybe problem with scanner.
16398	Al/CH 19 µm, Ti (0002) 40 µm	Ti 7 µm	~0.1	2.0	126	5.0	2.0	72	2.55	Moved other end of A trombone by 0.75". Various lines.
16399	Al/CH 19 µm, Ti (0002) 40 µm	Ti 7 µm	~0.1	2.0	135	5.0	2.0	70	2.55	Moved other end of A trombone by 0.75". Various lines.
16400	Al/CH 19 µm, Ti (0002) 40 µm	Ti 7 µm	~0.1	2.0	136	5.0	2.0	79	2.4	Moved other end of A trombone back 0.75". Apparently unshocked lines but not shocked.
16401	Al/CH 19 µm, Ti (0002) 40 µm	Ti 7 µm	~0.1	2.0	140	5.0	2.0	72	2.4	Shocked and unshocked lines, including previously unseen ones.

Notable events

1. 8 Dec: TRIDENT short-staffed because of illness and training.
2. 8 Dec: We were asked early pm to avoid disturbing the beam alignment into the Raman experiment in the north target area until the effect of convection currents could be explored (by mid/late pm).
3. 8 Dec: Insufficient port flanges were found for the number of windows required for diagnostics (maybe because of setting up for TXD and ellipsometry simultaneously). Tom Ortiz machined a new flange from a blank.
4. 9 Dec: Spent all day getting in each other's way and having to align and realign almost everything. Camera timing went smoothly. Time also spent hunting missing parts, getting chamber vacuum tight, etc.
5. 10 Dec: Ellipsometer CCD trigger signal found to be faulty. Tom Shimada tested relay - seemed OK. Worked fine when put back.
6. 11 Dec: Hot/cold stage operated essentially fine in air or vacuum. Radiant heater was awkward to position for adequate heating. Holder design made it fiddly to change targets with the chamber layout used. Radiant heater seemed to cause no damage or distortion to optical stages as close as 5 mm to the tungsten tube (Al foil interposed for additional shielding). Insulation failed on lamp circuit when position was adjusted with the base still warm.
7. 16 Dec: IPs seemed very insensitive to Ti He-like radiation.
8. 22 Dec: Line management encouraged us to fire Be from the first shot in the New Year. We resisted this on the basis that we had not completed the precursor W shots, and Be is much more toxic and expensive than W hence less appropriate while bringing the system back up after the break. In the event it took 5 shots before the minimum diagnostics were operating successfully, so Be cost, waste, preparation of samples, and availability for subsequent shots were spared this loss.
9. 5 Jan: Energy monitor failed to operate all day.
10. 6 Jan: Energy monitor failed to operate in the morning.
11. 6 Jan: pm started using attenuator along one of the ellipsometry paths to equalize initial amplitudes.
12. 7 Jan: Bug found in Roper software controlling pyrometry streak camera; fixed.
13. 9 Jan: Bug found in Retriever software controlling x-ray streak cameras: continuous clear when externally triggered.
14. 12 Jan: problem with flashlamps for amplifier in A beam. Target positioner failed (back up pm).
15. 13 Jan: inexplicably, a subset of the TRIDENT Toms objected to their all being renamed Igor for clarity during the remainder of this experiment. Retriever camera captured "noise signal" from N Kentech, with manual external triggering (partial success for use of cameras).
16. 14 Jan: problem with flashlamps for amplifier in A beam.
17. 14 Jan: light leak discovered in S Kentech intensifier.

Experimental observations

1. W foils were readily recovered with shock drive up to 208 J in 2.5 ns over a spot 1.5 mm in diameter, using a LiF release window.
2. Suspect we get Ti H-like over ~150 J in 2 ns at TRIDENT. Probably able to stretch x-ray pulse to 5 ns with one-beam double-pulse method.
3. All shocked Ti samples were lost from the Lorenzana holder: Tacky Wax/Scotch tape were not adequate to secure them to the polyethene substrate. The more massive V sample was not lost.

Evaluation

1. "Determine shock melt conditions for Be using VISAR and ellipsometry."

   Ellipsometry reference data were successfully obtained for W through an LiF release window, to max energy at ~1.5 mm diameter. Be data were collected, but the ellipsometry signals showed a huge effect from relatively low drive pressures. It is therefore not clear whether ellipsometry will be suitable for detecting melt in Be specifically. High-resolution ellipsometry may make these measurements possible, but this should be regarded as high risk.

2. "Investigate strength and phase changes in shock-loaded Ti, V, Ta, and/or Fe."

   Wide-angle TXD data were obtained on crystals of Ti and V. The Ti showed clear line motion and apparently the appearance of new lines.

3. "Perform shock/recovery experiments on NiAl samples with VISAR and TXD."

   Beautiful VISAR records were obtained showing the elastic precursor and plastic wave in (110) and (111) crystals, also comparing GE and LANL material. TXD signals were obtained (moving lines). No samples were recovered because of conflict with TXD and VISAR diagnostics: the samples did not remain in the TXD target holder.

4. "Perform TXD and pyrometry development for subsequent TRIDENT campaigns."

   The emission spectrometry diagnostic was successfully fielded simultaneously with line VISAR and ellipsometry. Problems were encountered with the camera control software; once these were solved spectra were obtained. It is too early to say whether spectra included surface emission or just plasma light. There was also evidence of Raman-like lines.

   Some TXD development was performed as part of the NIF Materials IET studies.

5. "Obtain data relating to the dynamics of melting."

   Some Ga TXD shots were fired, but preshot Laue patterns were delayed by IWD-related issues in MST (these were to be obtained as a favor rather than through formal funding, so the work was performed at best effort). There may be useful data from the TXD records. Additional Sn VISAR/ellipsometry data were obtained, to calibrate the drive at higher pressures corresponding to melt on release.

Secondary objectives:

1. "Test of Tierney-Swift quadrature line VISAR."

   Quadrature signals were obtained; analysis will show whether these are usable data or whether more development is needed. The Forsman line VISAR was used simultaneously, so reference velocity histories are available.

2. "Test of x-ray yields using C beam."

   Cancelled because of a lack of time - effort devoted to solving problems with pyrometry camera.

3. "Trials of sample preheater/precooler."

   The LLNL preheater was tested on one (almost two) shots. Various problems were encountered, but this was valuable experience for future experiments.

4. "Test of x-ray radiography in 1D drive expt."

   Cancelled as per C beam x-ray yields.

5. "Test of x-ray streak cameras with CCD recording."

   The Retriever CCD cameras were fielded on the Kentech streak units. The triggering system on the Retriever cameras seemed to work incorrectly: manual triggering from outside the target room was used successfully.

Acknowledgements

Distribution

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