##  [Shock Timing](/for-users/experimental-capabilities/shock-timing) 

## Platform Purpose

The shock timing experiments conducted by the Capsule Tuning Integrated Experimental Team (IET) were the first cryogenic shock timing experiments in a series of sub-campaigns with the goal of tuning the ignition hohlraum and capsule design for ignition experiments that began in 2010. The experiments require 192 beams smoothed with continuous phase plates (CPPs), smoothing by spectral dispersion (SSD), and polarization smoothing (PS). Two types of cryogenic hohlraum with deuterium-filled capsules equipped with a re-entrant cone are used.

These shots set the shock speed and timing in the cryogenic fuel of an ignition capsule by using capsules with liquid D2 as emulators. For shocks driven by radiation temperatures below about 180 eV, the Velocity Interferometer System for Any Reflector (VISAR) reflection off the shock front in D2 is used. For shocks driven by radiation temperatures >180 eV, the Streaked Optical Pyrometer (SOP) is used to measure the break-out time of the shock through a re-entrant Au witness plate. In addition, the Dante spectrometer is used to infer the strength of the first shock from the rise in radiation temperature.

## Laser and Target Configurations

The laser and target configurations for this platform are summarized below:

| Target | \# beams | Laser energy/Pulse width |
|---|---|---|
| Au:B hohlraum, cryogenic, H-He gas fill | 192 | 160-kJ, 14-nsec shaped pulse |
| Au:B-lined U hohlraum, cryogenic, H-He gas fill | 192 | 750-kJ, 15-nsec shaped pulse |
| Au:B hohlraum, cryogenic, H-He gas fill | 192 | 160-kJ, 14-nsec shaped pulse |
| Au:B-lined U hohlraum, cryogenic, H-He gas fill | 192 | 750-kJ, 15-nsec shaped pulse |



Hohlraums will be "Scale 1.07" . Dimensions for this hohlraum are summarized below:

| Target | Hohlraum    Length | Hohlraum    width | Laser Entrance    Hole (LEH) |
|---|---|---|---|
| Scale 1.07 | 10.01 mm | 5.44 mm | 3.01 mm |



The laser employs PS and SSD, with a nominal bandwidth of 60 GHz for the latter. A 2-color wavelength detuning, typically 0.5Å between inner and outer cones also is required. Additional detailed modifications to the laser and target will be made to suit the needs of particular experiments.

A generic experimental configuration is shown below:

 ![Experimental configuration showing D2 filled cone sphere](https://lmf.llnl.gov/sites/lmf/files/styles/orig/public/2023-11/shock_timing_fig1.jpg?itok=za08L4QS "Experimental Configuration 3")

## Diagnostic Configuration

Standard diagnostics for this platform and their location (elevation, azimuth) are provided below. See [Chamber Geometry](https://lmf.llnl.gov/for-users/experimental-capabilities/chamber-geometry) and [Diagnostics](https://lmf.llnl.gov/for-users/experimental-capabilities/diagnostics) for additional information.

| Diagnostic | Location |
|---|---|
| VISAR/SOP | DIM 90-315 |
| Dante-1 | Fixed (143-274) |
| FABS/NBI | Q31B, Q36B |
| FFLEX | Fixed (90-110) |
| SXI, Top/Bottom | Fixed ((18-123),(161-326)) |

**For further information on scientific opportunities at the NIF, please contact:**  
User Office  
PHONE: (925) 422-2179  
nifuseroffice \[at\] llnl.gov (nifuseroffice\[at\]llnl\[dot\]gov)