# Presentation: 782707

## Chicane Straight for Angular Slicing

**H. A. Padmore,  7/11/02**

**- need an angular kick of 1 mrad, so for 1% energy modulation we need a 100 mrad bend**
**- basic symmetric structure therefore has a -50, 100, -50 mrad chicane; total length 4.92 m**
**- problem is that the photon beam exits through the side of the sector arc chamber upstream of 6.0**

## Angular Slicing

**Angular Slicing**

**	****- ****	****for 1.55 eV 1st harmonic operation, 1.8 m straight length, Halbach hybrid structure**
**	****-  power calculations done for largest and shortest period; **
**	****	****	****	****- note that the 11 cm device is at a limit imposed by the ID of the vacuum chamber**
**	****	****	****	****- at other extreme, pulse length has decreased substantially, reducing S/B ratio**
**	****- we should use shortest period commensurate with not substantially effecting the machine**
**	****	****	****	****- eg. emittance increase will go as ~ B^3, so effect is 15 times greater for 11 cm device**
**	****	****	****	****	**

**period****	****gap****	****field****	****K****	****N****	****t**
**cm****	****mm****	****T****	****	****	****fsec**
** **
**20****	****63****	****0.8****	****15****	****9****	****24**
**19****	****56****	****0.87****	****15.4****	****9.5****	****25.4**
**18****	****50****	****0.94****	****15.9****	****10****	****26.7**
**17****	****44****	****1.03****	****16.3****	****10.6****	****28.3**
**16****	****38****	****1.12****	****16.8****	****11.2****	****30.0**
**15****	****32****	****1.24****	****17.4****	****12****	****32**
**14****	****26.8****	****1.37****	****18****	****12.8****	****34.2**
**13****	****21.7****	****1.54****	****18.7****	****13.8****	****36.8**
**12****	****16.9****	****1.74****	****19.5****	****15****	****40.05**
**11****	****12.5****	****1.97****	****19.7****	****16.4****	****43.8**

## Angular Slicing

**Angular Slicing**

**	****- ****	****need to add a new port upstream of 6.0**
**	****-****	****meeting convened July 2nd (Henderson, Schlueter, Paterson, Thur, Stevens, ****	****	****	****	****Heimann, Marks, Padmore, Duarte) to discuss chamber mod. options**
**	****-  conclusion was that the chamber could be modified in-situ**
**	****	****	****	****- needs approximately 1 m by < 1cm slot in the chamber and a ‘cap’ welded in place**
**	****- ****	****next step is to look at detailed chamber layout to make sure cut and weld is possible**
**	****	****	****	****	**

## Angular Slicing

**Angular Slicing**

**	****	****	****	****	****	****	****type****	****	****Ptot (W)****	****Ppeak (W/mrad^2)****	****PS angle (deg) 10 mm @ 2 m**
**	****	****	****	****	****	****	****	****	****	****	****	****for 20 W/mm^2**
**	**
**	****- ****	****bend 1****	****	****	****1.5 T 50 mrads****	****862****	****42****	****	****90**
**	****-  modulator 1****	****	****0.8 T 9 periods****	****1048****	****407****	****	****11.3**
**	****- modulator  2****	****	****1.98 T 20 periods****	****6355****	****2192****	****	****2**
**	****- bend 2****	****	****	****1.5 T 100 mrads****	****1724****	****42****	****	****90**
**	****- undulator 1****	****	****	****0.72 T 36 periods****	****780****	****1464****	****	****3.1**
**	****- undulator 2****	****	****	****1.0 T 75 periods****	****1254****	****4236****	****	****1.1**
**	****	****	****	****	**

## Angular Slicing

**Angular Slicing**

**	****- vacuum chamber can be similar to a regular ID chamber, ie. single piece construction **
**	****- saves space for transitions**
**	****- length ~ 5 m(4.92 m from edges of outside magnets)**
**	****- width dictated by 50 mrads x 5 m = 250 mm + beam aperture 20 mm + wall 2x20 mm = 310 mm**
**	****- photon stops can be easily integrated in chamber**
**	****- ~ 1m between end of chamber and sector arc chamber**
**	****	****	****- 50 mrads x 1 m = 50 mm; with +/- 20 mm beam aperture, 30 mm for laser port**
**	****	****	****- need to look at layout in the region of steering magnets, flex band, BPMs**
**	****	****	****	****	**

**laser**

## Angular Slicing

**Angular Slicing**

**	****- symmetric arrangement of angular slicing with undulator beam out of 6.0 port**
**	****	****	****- arrangement is 7.576 m long, ie. impossible!**
**	****	****	****- very large bend angles, eg. 200 mrads**
**	****	****	****	****	**

## Angular Slicing

**Angular Slicing**

**	****- asymmetric arrangement of angular slicing with undulator beam out of 6.0 port**
**	****	****	****- total length 6.696 mm long; still impossible**
**	****	****	****- leads to huge bend angles, eg. 340 mrads**
**	****- might be able to increase field in bends to 2 T and with reduction in modulator to 1.5 m, total = 5.6 m**
**	****	****	****	****	**

## Angular Slicing

**Angular Slicing**

**	****- ****	****symmetric arrangement looks possible and fits in normal straight**
**	****	****	****	****- needs machining of vacuum chamber in-situ**
**	****	****	****	****- need shielding door to be moved or sealed**
**	****	****	****	****- beamline doesn’t clash with 5.3.2**
**	****	****	****	****- next stage is to do a quick layout of the straight and arc sector at a more ****	****	****	****	****	****  detailed level to check real location of components**
**	****	****	****	****- check on impact on the machine of dipoles and Ids**
**	****	****	****	****	****- Sasha, calculations on emittance growth due to Ids**
**	****- ****	****asymmetric arrangement**
**	****	****	****	****- need to know impact on the machine of extremely large dipoles to 1st order**
**	****	****	****	****- if 1st cut machine analysis is OK, then proceed to evaluate practicality of 2 T**
**	****	****	****	****  ****dipoles of this length + 1st cut layout of the straight**
**	****	****	****	****	**