Performance Metrics: User Time for FY16

Experiment: E204 - Proposal for testing of metallic structures periodic structures at FACET

Shift Start: 2015-11-21 14:00:00

​ Brief Summary:

Goal of our study is to determine energy reach of mm-wave accelerators. 
The major obstacle in increase of accelerating gradient is rf breakdown. 
As for now E204 experiments are only systematic study that can relaibly measure rf breakdown 
in accelerating structures above 100 GHz. In this specific experiment we test new material 
- copper -silver and developing understanding of physics of a surface wave excited by the beam.

Experiment: E200 - Multi-GeV Plasma Wakefield Acceleration Experiments

Shift Start: 2015-11-21 00:00:00

​ Brief Summary:

We determined that the beam is focused "best" when the QS is set to -1 GeV if QS0 is on and -0.5 GeV if QS0 is off. 
This does not effect our ability to measure acceleration, deceleration, or a butterfly if created in a plasma interaction.

Experiment: E217 - Ionization and down-ramp injection proposal by the E200 team

Shift Start: 2015-11-20 17:00:00

​ Brief Summary:

E217 started diagnosing laser problems that are required to be fix for the experiment. Part way in the way, discovered that 
pre-amp mirrors are damaged. Cause is unknown, although cumulative damage is possible. 
They will need to be fixed before next shift.

Experiment: E210 - Trojan Horse Plasma Wakefield Acceleration

Shift Start: 2015-11-19 15:00:00

​ Brief Summary:

E210 looked at the FACET laser ionization ability (using the probe laser) in pure Hydrogen and 
Helium gas, which is a success. The laser spot size by an OAP is 23 x12 um.
 Plasma filament observed both in hydrogen and helium gas and we did energy scan for both gases.

Experiment: E201 - Wakefield Acceleration in Dielectric Structures

Shift Start: 2015-11-16 16:25:00

​ Brief Summary:

E201 looked at the excitation of potentially deleterious HEM modes as a function of offset. 
We found clear evidence of excitation with offset, as expected, in addition to a linear relationship
 between offset in structure and magnitude of offset downstream. 
We further examined the damping of the different modes by scanning charge and 
purposely exciting HEM modes via offsets.

Experiment: E217 - Ionization and down-ramp injection proposal by the E200 team

Shift Start: 2015-11-15 14:00:00

​ Brief Summary:

Interesting results regarding observation of plasma filament at high pressure. 
We were able to make plasma and observe deceleration but not acceleration.
 Late in the shift we lost the ability to make plasma, possibly indicating additional 
nearfield type diagnostic in the tunnel is needed.

Experiment: E201 - Wakefield Acceleration in Dielectric Structures

Shift Start: 2015-11-14 16:00:00

​ Brief Summary:

E201 team follows up on the issue of high field damping of CCR. 
The line of investigation is varying the structure parameters while keeping fixed the beam parameters.
 Data collected for the various tube sizes are being analyzed. 
Some anomaly regarding relative excitation strengths of TM01 and TM02 modes for one particular tube is being scrutinized. 
It was also observed for the same structure that the damping envelope for the TM01 and TM02 modes look distinctly different.

Experiment: E201 - Wakefield Acceleration in Dielectric Structures

Shift Start: 2015-11-14 16:00:00

​ Brief Summary:

Previous work at FACET has shown that strong fields induces a heretofore unexpected damping of the
 CCR wake produced by the beam in an SiO2 based dielectric wakefield accelerator (DWA).
 This work was done using one structure but many different beam charges. 
Further work has strongly discounted the effect of charge impact on the dielectric, or halo, generating this effect. 
In this shift, we wish to further study the interplay of both effects by holding the beam parameters constant and adjusting the DWA parameters. 
This will also provide insight into variation in damping with the frequency of the excited mode.

Experiment: E217 - Ionization and down-ramp injection proposal by the E200 team

Shift Start: 2015-11-13 16:00:00

​ Brief Summary:

A plasma was created solely with the laser and axilens and without the electron beam. 
Strong electron beam interaction was observed with deceleration and acceleration.

Experiment: E213 - Temporal Limits of Electron-Phonon Interactions

Shift Start: 2015-11-13 12:30:00

​ Brief Summary:

We successfully exposed new type of samples to short electron bunches. 
We will evaluate the mechanical effects of strong electromagnetic field on nano-patterned thin film structures.
 We varied the substrate (single crystal, polycrystalline or amorphous) and the material for films. 
This will enable us to test how fast can they deformation occur and what mechanisms are at play.

Also new types of resistive materials used in nonvolatile memory were tested for switching under the ultrashort electric and mechanical stress induced by the beam.
 This will help understand the mechanism behind the switching and long term stability of memory.

Experiment: E201 - Wakefield Acceleration in Dielectric Structures

Shift Start: 2015-11-08 19:00:00

​ Brief Summary:

Fully characterizing the fields in the dielectric accelerating structure is necessary if it is to be employed in future advanced accelerators as the fields
 transverse to the accelerating fields are potentially detrimental. 
We were able to characterize the effect of imperfect alignment through a dielectric structure and 
measure the forces acting on the beam when not perfectly aligned.

Experiment: E204 - Proposal for testing of metallic structures periodic structures at FACET

Shift Start: 2015-11-08 12:00:00

​ Brief Summary:

Successful commissioning of the electronics and of the data acquisition system of RadiaBeam pyrodetector array. 
With the radiation generated by the electron beam, hitting a target, we saw signal in the single pyrodetector channels. 
The pyrodetector array sampled the spatial distribution of the generated radiation.

Experiment: E201 - Wakefield Acceleration in Dielectric Structures

Shift Start: 2015-11-07 12:30:00

​ Brief Summary:

Previous experiments which showed field based damping of the wakefield excited in SiO2 dielectric based accelerators also showed a fundamentally 
different process when the beam was allowed to impinge on the structure (or beam scraping). 
We set out to more precisely control the rate at which we spoil the beam to
 measure the onset of this only recently observed effect. We were successfully able 
to induce the effect and now look to match this effect to our models.

Experiment: E217 - Ionization and down-ramp injection proposal by the E200 team

Shift Start: 2015-11-06 16:00:00

​ Brief Summary:

We showed that we can make a plasma with the laser, but it seems that we were just over the minimum laser energy 
limit for this particular axicon lens. We also concluded that the previous shift likely didn't see 
plasma because it required the electron beam for us to observe it.

Experiment: E200 - Multi-GeV Plasma Wakefield Acceleration Experiments

Shift Start: 2015-11-05 16:00:00

​ Brief Summary:

Checkout shift for the plasma formation experiments. Plasma was not visible via the laser or e-beam.

Some issues involving diagnostics were found and are to be explored and cleared during the access tomorrow.

Experiment: E201 - Wakefield Acceleration in Dielectric Structures

Shift Start: 2015-11-01 14:00:00

​ Brief Summary:

We performed tests of Coherent Cerenkov Radiation from Dielectric Lined Waveguides (DLW) signal strength as a function of beam charge 
in order to determine the origin of the heretofore unidentified damping which prevents extraction of large amounts of
 THz from DLW. The scaling seen during this shift indicates that field strength and not impact ionization is the cause. 
Further study of correlations of bunch charge with halo, at FACET, are needed to finish the analysis.

Experiment: E201 - Wakefield Acceleration in Dielectric Structures

Shift Start: 2015-10-31 16:00:00

​ Brief Summary:

This shift, E201 resolves for the first time a full CCR scan that exhausts all of the interferometer motor range. 
This is a big step forwards. We also have success in resolving HEM modes. We have strong data to support 
the idea of wakefield damping by induced conductivity.

Experiment: E201 - Wakefield Acceleration in Dielectric Structures

Shift Start: 2015-10-30 18:30:00

​ Brief Summary:

E201 continues its mission in dielectric wakefield. This run, we wanted to test some idea about wakefield damping due to strong field. 
This phenomenon has only been recently observed. In addition, we want to add to our data the measurement of CCR absolute energy. 
We did not see a significant increase in CCR pulse length with longer tubes. We also did not see a significant amount of CCR energy as expected. 
This can either be a detector sensitivity or the damping mentioned above. When we come back for next shift with longer bunch length 
and lower charge, we will be able to tell.

Experiment: E210 - Trojan Horse Plasma Wakefield Acceleration

Shift Start: 2015-10-25 10:00:00

​ Brief Summary:

No ionization related plasma glow observable in hydrogen at different pressures and laser energies. 
Substituting the gas by argon at various pressures and maximum laser energy also did not lead to any visible signal.

Experiment: E200 - Multi-GeV Plasma Wakefield Acceleration Experiments

Shift Start: 2015-10-22 18:00:00

​ Brief Summary:

We did all the things.