BIA’s Director Review, September 17 2010

Accelerator Improvements FY11-16

Fulvia Pilat

A list of accelerator improvements through FY16 has been presented and discussed at the recent Operations Review [ref. Arne Freyberger’s talk]

Will present and use this as a basis for this discussion

One more project (upgrade of chicanes to allow larger path-length adjustment capacity) identified and added

Discussion of what could be funded through BIA to benefit from the overall Program oversight.

Accelerator Projects

June 10

List of Accelerator Projects

Chicanes Upgrade estimate: 650 K$

June 10

Injector Upgrade

Upgrade the 65 MeV injector to a 125 MeV injector compatible with 12GeV CEBAF.

Optimize warm RF and 1 cryomodule section for the new 200 kV capable gun.

Inj. Upgrade - Cryomodule (R100) OPS 1.5 M$ FY11-12Inj. Upgrade - Build 1/4 Cryomodule AIP 2.0 M$ FY11-13Inj. Upgrade – Integration OPS 3.3 M$ FY11-13

Mission Critical

June 10

Gradient Maintenance

C50 OPS ~10M$ FY13-16RF power upgrade AIP ~2M$ FY13-15

June 10

Diagnostics Improvements

In general, need to strengthen CEBAF instrumentation• Instrumentation for 12 GeV copy of 6 GeV• No formal instrumentation group in Operations

• ODR for non-invasive beam size monitoring• improved diagnostics on beam transport to the high power dump• upgrade to digital imaging

Projects:Optical Diffraction Radiation Diagnostics AIP 220K FY12-13BSY Diagnostics suite AIP 67K FY11Upgrade imaging diagnostics AIP 250K FY16

June 10

Global event link system

CEBAF does not have an event link system, machine completely asynchronous

Exploit the installed high sample rate control electronics (digital LLRF) develop additional high sampling rate systems (BPM, C50 LLRF) develop an analysis system, data visualization software, archive systems and event trigger system to create high speed snapshots of CEBAF accelerator control system.

AIP ~700K$ FY14-16

June 10

Chicanes Upgrade - motivation

• The acceleration passes in the CEBAF must be held synchronous, compensated against daily and seasonal variations in the temperature of the beam enclosure and ground motion

• As the beam energy was increased from 4 GeV to 6 GeV, some of the time-of-flight (or “path length”) adjustment chicanes became power-supply limited. Path length control was supplemented by adjusting the beam trajectory in the recirculation arcs.

• Chicane path length control is further diminished in the 12 GeV upgrade. The baseline plan was to forego upgrading the path length chicane dipoles with the beam energy and adjust the master oscillator frequency as the principal accommodation for variations in circulation path length. This is not sufficient due to arc to arc variations ~10o.

• Maintaining the accelerator “phase length” rather than time-of-flight restores correction capability but involves changes in the physical location of the recirculation arcs due to reduced chicane delays. Not practical to move and resurvey magnets 2-4 times a year

.Multiple control options exist satisfying the requirements with a differing mix of capital cost,operational time consumed, and technical or schedule risk.

Doubling the power supply capacity of the path length chicanes provides sufficient margin to cover historically experienced variability

Mike Tiefenback

June 10

Chicanes implementation

• Nine 600A, 110V power supplies at $50K each, includes spare. All but arc 1. $450K total

• 2.5” H steel on ten BY magnets in arcs 5-9. $100K• 3mm shims for eight BW magnets in hand• check cooling for arcs 1-4 at 1000 A/cm2. Likely OK as

other labs have run 1600 A/cm2. • Engineering labor, overhead, etc. $100K• Estimated total $650K

Jay Benesch

June 10

Accelerator Projects and 12GeV

Injector Upgrade:1. R100: Critical for 12 GeV, project well underway2. 200keV Gun: Not needed until 12GeV parity experiments3. Warm RF mods: Not needed until 12GeV parity exp.4. New ¼ cryo: Not needed until 12GeV parity exp.

Dog-Leg Chicane Upgrade:Critical for 12GeV

Gradient Maintenance:Critical for 12GeV FY15 and beyond, Accelerator Division has a

positive track record of managing Gradient Maintenance (e.g. C50 program)

Diagnostics Improvements: Not critical for 12GeVGlobal Event Timing: Not Critical for 12GeV