Michael Hahn Reporting for TID Vacuum Group and ESRF-II · PDF file · 2014-04-10ESRF –UPGRADE PHASE I –MACHINE SIDE Page 5 OLAV IV April 2014 l M ... Page 7 OLAV IV April 2014

Michael Hahn – Reporting for TID Vacuum Group and ESRF-II project team

ESRF-II - OVERVIEW

Outline

• ESRF Upgrade Phase I & II

• TDS – Proposal for a new SR

• Constraints

• Vacuum design options

• Chosen strategies

• Pressure simulations

• Implementation, Logistics

• Timeline

• Discussion

Page 2 OLAV IV April 2014 l M. Hahn

MOTIVATION: ESRF – UPGRADE


• Phase I & II of the

ESRF upgrade

• Phase 1 (2009 – 2015)

- new Experimental halls

and lab / office buildings

- Some source

improvements (6m

straight sections, HOM

damped cavities, Solid

state amplifiers…)

- Beamline upgrades and

refurbishments – many

long beamlines

- Close to completion

• Phase 2 (2016-2021)

Substantial source

upgrade

- Replace the lattice of

the electron storage ring -

- Proposal, Technical

design study report (TDS)

close to completion

ESRF – UPGRADE PHASE I - BEAMLINES


UPBL01 / ID01

UPBL02 / ID31

UPBL04 / ID16A

UPBL04 / ID16B

UPBL06 / ID20

UPBL07 / ID32

UPBL09A / ID02

UPBL09B / ID09TR

UPBL10 / ID30

UPBL11 / ID24

ID10 Refurbishment

ID15 Refurbishment

ID19 Refurbishment

ID31 -> ID22 Transfer

ESRF – UPGRADE PHASE I – MACHINE SIDE


Phase I & II of the ESRF upgrade

• Phase 1 (2009 – 2015)

• 8 x extension of straight sections from

5m to 6m

• 1 x extension from 5m to 7m to receive

three HOM-damped cavities and

canted insertion devices

• Solid-State amplifiers to replace

Klystrons driving cavities on the

booster synchrotron and storage ring

• New In-Vacuum undulators optimized

for longer straights, cryo-cooled

(100K) and RT

• Test of the injector to allow for

Topping-up

MOTIVATION FOR PHASE II

Motivation: Shrinking the horizontal emittance of the electron beam translates into

substantial gain in brilliance: Main quality parameter of a synchrotron light source


MOTIVATION


ESRF New lattice

Lattice type DBA HMB

Circumference [m] 844.390 843.979

Beam Energy [GeV] 6.04 6

Beam Current [mA] 200 200

Natural emittance [pm] 4000 147

Energy spread [%] 0.106 0.095

MOTIVATION


Expected gain in brilliance in function of existing and future insertion devices: Courtesy Joel Chavanne (ESRF)

IDEA


The “old” double bend achromat lattice (all dipoles, quadrupoles, sextupoles) in the 32 vacuum

cells needs to be removed to make place for the new arrangement

The seven bend lattice requires much stronger quadrupoles and sextupoles and few octupoles .

The magnetic field of the dipoles outside the central part will have gradients

The source for the Bending magnet beamlines will be a 3 pole wiggler in the central part

BEAM LIFETIME & LOSSES


1

1

T1

V

Mode Intensity

[mA]

Bunch intensity

[mA]

Vertical

emittance

[pm.rad]

Lifetime

[h]

Uniform 200 0.202 5 8.5

7/8+1 200 0.23 5 7.5

16-bunch 90 5.62 60 2.42

4-bunch 40 10 60 1.78

• As compared to the existing machine

(electron beam vacuum lifetime > 100h)

the machine is going to be dominated by

losses due to intrabeam scattering

(Touschek)

• Bremsstrahlung issues still exist, so

vacuum pressure should remain in the

same order of magnitude

• Shorter effective length of the straight

section due to increase of the number of

dipole magnets helps to deal with

Bremsstrahlung / inelastic scattering

• On the negative side we might have to

deal with a more activated vacuum

system when entering the tunnel for

intervention

VACUUM DESIGN OPTIONS / CONSTRAINTS


• Ambitious time schedule: Limit time between start of removal of the old machine and

commissioning of the new one to less than one year

• Stay within a budget envelope of 100 M€ for the accelerator project . Re-use equipment where

possible, avoid long and complicated procurement procedures

• Re-use the existing stock of 5m long ID vacuum chambers and the corresponding In-Vacuum

undulators

• Despite Touschek domination of the electron beam lifetime and the shorter total length of the

straight sections which helps for Bremsstrahlung issues the ALARA principle applies: Working

objective for the average pressure on the beam path is 1 x 10-9 mbar

• On the negative side we will have to deal with a more activated vacuum system when entering the

tunnel for intervention

POSSIBLE VACUUM DESIGN OPTIONS


Collect all dipole radiation on discrete absorbers

• Antechamber is required to

transport photon beams to users

and absorbers

• Accessibility of the antechambers

allows to mount absorbers and

pumps there

• Steel as construction material is

required to avoid collapsing of the

chambers in the low gap regions

• Impedance studies are not yet

completed

POSSIBLE VACUUM DESIGN OPTIONS


Intense use of NEG coatings: Fully coated machine for either rely only on distributed absorbers

(Max-IV) or combination of lumped absorbers and distributed absorbers up to about 150 W/m

• Idea: Apply NEG Coating

to all vacuum chambers of

the “standard cell”

(dipoles, quadrupoles,

sextupoles, octupoles)

• Profit from the upgraded

ESRF coating facility

(double surface) which

provides three coating

benches

• It was estimated that 50%

of the required 700m of

coated chambers (plus

spare) could have been

coated in-houseHorizontal Vertical

Cell centre ±8 mm ±5.5 mm

Cell ends ±15 mm ±10 mm

PROPOSED SOLUTION


• 7 lumped absorbers ,

2 crotch absorbers

per cell - discrete

vacuum pumps

• NEG coating only on

the upstream and

downstream ID

vacuum chambers to

partly compensate for

the higher power

deposition on the ID

chamber

• Keep the principle of

two gate valves per

cell, one isolates the

lattice part from the

insertion device

sector

VACUUM INSTRUMENTATION LAYOUT


Arrangement of UHV pumps and measurement on the new standard cell – Meunier, Guerin (ESRF Vacuum Group)

VACUUM EQUIPMENT KEYWORDS


• 2 IMG in a typical ID sector, 4 IMG in the standard cell sector

• Pirani gauges interlock in each sector for protection of ion pums

• Penning gauge interlock for valve closing

• RGA downstream crotch absorber2 , additional port on crotch absorber 1

• RGA downstream ID chamber

• Re-use of smaller ion pumps and NEG pumps coming from existing machine

• Due to required forerun purchase of UHV pumps necessary

BEAM POSITION MONITORS


Courtesy Kees Scheidt / ESRF

• BPM electrodes with 6mm (4 or 5 in

the central area)

• Electrodes will be welded to

massive BPM blocks to be welded to

the vacuum chamber

• There will be one reserved area

(CH10) for beam diagnostics such

as special bpm, stripline chambers,

current monitors etc.

• A first experimental BPM according

to the new specs is going to be

installed in the existing machine in

summer

PRESSURE SIMULATION


Crotch Absorber

PRESSURE SIMULATION


• Comparing the pressure distribution in one (of 32) vacuum cell between proposal and

existing machine

• Conductance based calculation, the same model has been applied for both cases, for the

existing machine we could compare to measurements and validate the model

• This work has been done by Hugo Pedroso Marques, more details will follow in his

presentation

PRESSURE SIMULATION – STARTUP PLOT


LOGISTICS


• The disassembly of the existing machine will be difficult due to the time

constraints to get the new compenents in on one hand and the fact that all

equipment needs to be measured and qualified in terms of activation by the

Safety Group on the other

• Pre-assemble magnets, vacuum chamber and baking equipment on the girder

and bring the complete assembly to the tunnel

• ESRF overhead craned cannot take the mass of at least girder 3 (maximum load

6.3t) so it is envisaged to bring the assemblies through two dedicated tunnel

openings and slide them to position

IMPLEMENTATION - ASSEMBLY


• Components (magnets, vacuum chambers, etc. ) are delivered to a

reception building outside ESRF

• Components are delivered to a special assembly area at ESRF with

access to the SRTU for pre-assembly

• The chambers are assembled with the vacuum chamber, after the

completed pre-bake of a girder the chambers are pinched off and wait

transport to the final destination for in-situ bake

• It is envisaged to have on the first day of the long shutdown 8 cells

(32 girders) ready to go, so a complete re-use of existing pumps and

gate valves is not possible

IMPLEMENTATION – INSTALLATION & BAKE

OLAV IV April 2014 l M. HahnPage 23

• In-situ heating – Permanent installation inside

multipole magnets, dismountable on dipoles

• Silicon rubber, glass fiber and Kapton heaters are

going to be investigated, a mixed solution is

probable due to the different constraints

• Thermal simulation by finite elements will be

verified by lab measument with magnet

(mockups)

• It is envisaged to replace the mobile baking racks

by fix-wired power electronics

TIMELINE

• Technical design study

will be give to ESRF SAC

and APAC

• They produce a

proposal for the ESRF

council, to be discussed

in summer meeting (June

2014)

• Decision of the council

expected for the autumn

meeting (November 2014)

• General tendency is very

positive so technical

design will continue and

prototyping starts “now”,

recruitment for about 20

more positions started


DISCUSSION

Thank you for your attention

Page 25 OLAC IV April 2014 l M. Hahn

Documents

Michael Hahn Reporting for TID Vacuum Group and ESRF-II · PDF file · 2014-04-10ESRF –UPGRADE PHASE I –MACHINE SIDE Page 5 OLAV IV April 2014 l M ... Page 7 OLAV IV April 2014