# Analysis of the LSC microbunching instability in MaRIE linac reference design

## Abstract

In this report we estimate the effect of the microbunching instability in the MaRIE XFEL linac. The reference design for the linac is described in a separate report. The parameters of the L1, L2, and L3 linacs as well as BC1 and BC2 bunch compressors were the same as in the referenced report. The beam dynamics was assumed to be linear along the accelerator (which is a reasonable assumption for estimating the effect of the microbunching instability). The parameters of the bunch also match the parameters described in the referenced report. Additionally, it was assumed that the beam radius is equal to R = 100 m and does not change along linac. This assumption needs to be revisited at later studies. The beam dynamics during acceleration was accounted in the matrix formalism using a Matlab code. The input parameters for the linacs are: RF peak gradient, RF frequency, RF phase, linac length, and initial beam energy. The energy gain and the imposed chirp are calculated based on the RF parameters self-consistently. The bunch compressors are accounted in the matrix formalism as well. Each chicane is characterized by the beam energy and the R56 matrix element. It was confirmed that themore »

- Authors:

- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

- Publication Date:

- Research Org.:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1327984

- Report Number(s):
- LA-UR-16-27252

TRN: US1700331

- DOE Contract Number:
- AC52-06NA25396

- Resource Type:
- Technical Report

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 43 PARTICLE ACCELERATORS; FREE ELECTRON LASERS; LINEAR ACCELERATORS; BEAM DYNAMICS; BEAM BUNCHING; INSTABILITY; MATRICES; COMPRESSION; COMPRESSORS; GAIN; LENGTH; PEAKS; MATRIX ELEMENTS; ACCELERATION; KILO AMP BEAM CURRENTS; space charge, microbunching instability, electron accelerator

### Citation Formats

```
Yampolsky, Nikolai.
```*Analysis of the LSC microbunching instability in MaRIE linac reference design*. United States: N. p., 2016.
Web. doi:10.2172/1327984.

```
Yampolsky, Nikolai.
```*Analysis of the LSC microbunching instability in MaRIE linac reference design*. United States. doi:10.2172/1327984.

```
Yampolsky, Nikolai. Thu .
"Analysis of the LSC microbunching instability in MaRIE linac reference design". United States.
doi:10.2172/1327984. https://www.osti.gov/servlets/purl/1327984.
```

```
@article{osti_1327984,
```

title = {Analysis of the LSC microbunching instability in MaRIE linac reference design},

author = {Yampolsky, Nikolai},

abstractNote = {In this report we estimate the effect of the microbunching instability in the MaRIE XFEL linac. The reference design for the linac is described in a separate report. The parameters of the L1, L2, and L3 linacs as well as BC1 and BC2 bunch compressors were the same as in the referenced report. The beam dynamics was assumed to be linear along the accelerator (which is a reasonable assumption for estimating the effect of the microbunching instability). The parameters of the bunch also match the parameters described in the referenced report. Additionally, it was assumed that the beam radius is equal to R = 100 m and does not change along linac. This assumption needs to be revisited at later studies. The beam dynamics during acceleration was accounted in the matrix formalism using a Matlab code. The input parameters for the linacs are: RF peak gradient, RF frequency, RF phase, linac length, and initial beam energy. The energy gain and the imposed chirp are calculated based on the RF parameters self-consistently. The bunch compressors are accounted in the matrix formalism as well. Each chicane is characterized by the beam energy and the R56 matrix element. It was confirmed that the linac and beam parameters described previously provide two-stage bunch compression with compression ratios of 10 and 20 resulting in the bunch of 3kA peak current.},

doi = {10.2172/1327984},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Thu Sep 22 00:00:00 EDT 2016},

month = {Thu Sep 22 00:00:00 EDT 2016}

}