# ON-LINE NONLINEAR CHROMATICITY CORRECTION USING OFF-MOMENTUM TUNE RESPONSE MATRIX

## Abstract

In this article, we propose a method for the online nonlinear chromaticity correction at store in the Relativistic Heavy Ion Collider (RHIC). With 8 arc sextupole families in each RHIC ring, the nonlinear chromaticities can be minimized online by matching the off-momentum tunes onto the wanted tunes given by the linear chromaticities. The Newton method is used for this multi-dimensional nonlinear optimization, where the off-momentum tune response matrix with respect to sextupole strength changes is adopted. The off-momentum tune response matrix can be calculated with the online accelerator optics model or directly measured with the real beam. In this article, the correction algorithm for the RHIC is presented. Simulations are also carried out to verify the method. The preliminary results from the beam experiments taken place in the RHIC 2007 Au run are reviewed.

- Authors:

- Publication Date:

- Research Org.:
- Brookhaven National Lab. (BNL), Upton, NY (United States)

- Sponsoring Org.:
- Doe - Office Of Science

- OSTI Identifier:
- 910413

- Report Number(s):
- BNL-77538-2007-CP

R&D Project: 18031; TRN: US0704212

- DOE Contract Number:
- DE-AC02-98CH10886

- Resource Type:
- Conference

- Resource Relation:
- Conference: 22ND PARTICLE ACCELERATOR CONFERENCE; ALBUQUERQUE, NEW MEXICO; 20070625 through 20070629

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 43 PARTICLE ACCELERATORS; ACCELERATORS; ALGORITHMS; HEAVY IONS; NEWTON METHOD; OPTICS; OPTIMIZATION

### Citation Formats

```
LUO,Y., FISCHER, W., MALISKY, N., TEPIKIAN, S., and TROBJEVIC, D.
```*ON-LINE NONLINEAR CHROMATICITY CORRECTION USING OFF-MOMENTUM TUNE RESPONSE MATRIX*. United States: N. p., 2007.
Web.

```
LUO,Y., FISCHER, W., MALISKY, N., TEPIKIAN, S., & TROBJEVIC, D.
```*ON-LINE NONLINEAR CHROMATICITY CORRECTION USING OFF-MOMENTUM TUNE RESPONSE MATRIX*. United States.

```
LUO,Y., FISCHER, W., MALISKY, N., TEPIKIAN, S., and TROBJEVIC, D. Mon .
"ON-LINE NONLINEAR CHROMATICITY CORRECTION USING OFF-MOMENTUM TUNE RESPONSE MATRIX". United States. https://www.osti.gov/servlets/purl/910413.
```

```
@article{osti_910413,
```

title = {ON-LINE NONLINEAR CHROMATICITY CORRECTION USING OFF-MOMENTUM TUNE RESPONSE MATRIX},

author = {LUO,Y. and FISCHER, W. and MALISKY, N. and TEPIKIAN, S. and TROBJEVIC, D.},

abstractNote = {In this article, we propose a method for the online nonlinear chromaticity correction at store in the Relativistic Heavy Ion Collider (RHIC). With 8 arc sextupole families in each RHIC ring, the nonlinear chromaticities can be minimized online by matching the off-momentum tunes onto the wanted tunes given by the linear chromaticities. The Newton method is used for this multi-dimensional nonlinear optimization, where the off-momentum tune response matrix with respect to sextupole strength changes is adopted. The off-momentum tune response matrix can be calculated with the online accelerator optics model or directly measured with the real beam. In this article, the correction algorithm for the RHIC is presented. Simulations are also carried out to verify the method. The preliminary results from the beam experiments taken place in the RHIC 2007 Au run are reviewed.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {2007},

month = {6}

}