Getting the Booster to 2010

Eric PrebysDecember 20, 2002

• Outine

• Longevity Issues

• Non-radiation related

• Radiation related

• Personnel

• Performance Issues

• Limiting Factors

• Plan

Longevity Issues (non-radiation)

• GMPS (upgraded, OK)• Transformers (serviced, OK)• Vacuum system (being update, finished 2003)• Kicker PS charging cables

– Run three times over spec– Fail at the rate of about 1/month – AFTER A CERTAIN NUMBER OF

PULSES.– Seven spare coils– Evaluating improved design (better cable, LCW-filled heliac, etc)

• Low voltage power supplies, in particular Power 10 Series:– Unreliable, some no longer serviced.– Starting search for new supplier and evaluate system to minimize number

of different types.– Probably a few $100K to upgrade system.

Longevity Issues (non-radiation, cont’d)

• RF Hardware– (original) Copper tuner cooling lines are beginning to spring leaks.

Difficult to repair because they’re hot.

• High Level RF– More or less original.– Our highest maintenance item.– Will probably last, BUT expensive to maintain.– John Reid and Ralph Pasquinelli feel a new solid state system would pay

for itself ($5.5M) in about four years.

• Low Level RF– Many old modules, some without spares, some without drawings.– An upgrade plan in place.– Not expensive, but NEED people.

Longevity Issues (radiation related)

• We’ve seen failures in ion pump HV lines -> planning to replace.

• Hoses on beam valves will be replaced with copper of stainless.

• Looking at other miscellaneous cabling and hoses.• Magnet insulation:

– Biggest worry– We have no idea how close we are– During January shutdown

• Will remove some existing dosimetry and evaluate• Will put in widely distributed new dosimetry.• Take these numbers to the people who know.

Longevity Issues: Personnel

• Several key people will likely retire before 2010.• We need at least one new hire at the Engineer or

Engineering Physicist level to insure continuity.

Some Cold Hard Facts about the Proton Future

• Running as we are now, the Booster can deliver a little over 1E20 protons per year – this is about a factor of four over typical stacking operations, and gives MiniBooNE about 20% of their baseline.

• NuMI will come on line in 2005, initially wanting about half of MiniBooNE’s rate, but hoping to increase their capacity – through Main Injector Improvements – until it is equal to MiniBooNE.

• Whatever the lab’s official policy, there will be great pressure (and good physics arguments) for running MiniBooNE and NuMI at the same time.

• -> By 2006 or so, the Proton Source will be called upon to deliver 10 times what it is delivering now.

• At the moment, there is NO PLAN for achieving this, short of a complete replacement!

Limitations to Total Booster Flux

• Total protons per batch: 4E12 with decent beam loss, 5E12 max.

• Average rep rate of the machine:– Injection bump magnets (7.5Hz)– RF cavities (7.5Hz, maybe 15 w/cooling)– Kickers (15 Hz)– Extraction septa (now 4Hz, 7.5 after Jan. shutdown)

• Beam loss– Above ground:

• Shielding• Occupancy class of Booster towers

– Tunnel losses• Component damage• Activiation of high maintenance items (particularly RF cavities)

Of particular interest to NUMI

Our biggest concern

Proton Timelines

• Everything measured in 15 Hz “clicks”• Minimum Main Injector Ramp = 22 clicks = 1.4 s• MiniBoone batches “sneak in” while the MI is ramping.• Cycle times of interest

– Min. Stack cycle: 1 inj + 22 MI ramp = 23 clicks = 1.5 s– Min. NuMI cycle: 6 inj + 22 MI ramp = 28 clicks = 1.9 s– Full “Slipstack” cycle (total 11 batches):

6 inject+ 2 capture (6 -> 3)+ 2 inject+ 2 capture (2 -> 1)+ 2 inject+ 2 capture (2 -> 1)+ 1 inject+ 22 M.I. Ramp----------------------39 clicks = 2.6 s

Summary of Proton Ecomomics

 

Batches Protons delivered ( x E12 pps)* Total Scenario Cycle (clicks)

prepulse Stack MB NuMI

Rep rate (ave. Hz) Stack MB NuMI E12 /RunII

Stack 23 2 1 2.0 3.3 0. 0. 3.3 1.

Stack/MB 23 2 1 8 7.2 3.3 26.1 0. 29.3 9.0

Stack/NuMI 28 2 1 5 4.3 2.7 0. 13.4 16.1 4.9

Stack/NuMI/MB 28 2 1 10 5 9.6 2.7 28.8 13.4 42.9 13.1

Slipstack/NuMI 39 2 2 9 5.0 3.8 0. 17.3 21.2 6.5

Slipstack/NuMI/MB 39 2 2 13 9 10.0 3.8 25.0 17.3 46.2 14.2

Booster Hardware Issues Radiation Issues

MiniBooNE baseline 5E20 p/year

*assuming 5E12 protons per batch

NUMI “baseline” = 13.4E12 pps x 2E7 s/year 2.7E20 p/year

Right now we’re at roughly 1/5 of the MiniBooNE baseline

Typical Booster Cycle

Various Injected Intensities

Transition

Intensity (E12)

Energy Lost (KJ)

Time (s)

Booster Losses (Normalized to Trip Point)

BRF11: 200 mR/hr @ 1ft

BRF15: 300 mR/hr @ 1ft

Booster Tunnel Radiation Levels

Activation in Booster Tunnel (6 hour cooldown)

0

500

1000

1500

2000

2500

L20

L21_

RF9_ds

S21

L22_

RF12_us

L23_

RF13_us

L23_

RF14_ds

L24_

RF15_ds S24 S1 L3 S3 L5 S6 L8 L9 L1

0S11 S12 L1

3S13

L14_

RF2_us

L15_

RF3_us

L15_

RF4_ds

L16_

RF5_ds

S16

L17_

RF8_us

L18

L19_

RF17_ds S19

Standard Locations (some contact, some 1ft)

mR

/hr 28-Aug-02

17-Dec-02

• On the last access

• The people doing the radiation survey got about 20 mR.

• Two technicians received 30 mR doing a minor HV cable repair.

• We’re at (or past??) the absolute limit on our overall activation

Hardware Improvements to Booster

• Shielding and reclassification of Booster towers: complete 2001• New extraction septum (MP02) power supply: complete 11/02• New extraction septum: magnet complete. To be installed 1/03• Collimation system: complete, but cannot be used until…• Collimation system shielding: 75 tons of steel to be stacked 1/03• Time line improvements (very important for MiniBooNE

operation): more or less complete.• More cables for extraction septum (will allow 15 Hz

operation): ??• New injection bump magnets: ??• New RF cavities: ??

Plan

• All near term hardware improvements will be complete by early to mid 2003. At the point the Booster will physically be able to run a 7.5 Hz.

• Proceed with tuning improvements (C. Ankenbrandt coor.):– IPM calibration (Tomlin, Spentzouris, Lackey).– Orbit correctors: complete, working out operational issues

(Prebys, Coney).– Precision lattice measurement: (Lackey, Coney, new grad.

Student).– Transition studies (gamma-t jump??): (Jackson et al.)– Damping improvements: Pellico + ??

New RF System

• The existing RF cavities form the primary aperture restriction (2 ¼” vs. 3 ¼”).

• They are high maintenance, so their activation is a worry.• There is a plan for a new RF system with 5” cavities:

– Powered prototype built– Vacuum prototype ready for summer installation– Second prototype to be built by university machine shops?

• Total cost: $5.5M cavities + $5.5M power supplies (maybe use old ones)

• Is it worth it? On of the questions for the study group is how much improvement we might expect.

Upgrade Cost EstimateTUNERNew ferrite cores 28 $500 $14,000New copper disks 28 $300 $8,400End caps 2 $300 $600Center hub casting 1 $5,000 $5,000Center conductor cones 2 $1,500 $3,000Internal bus package 1 $5,000 $5,000External bus package 1 $5,000 $5,000Stem 1 $1,500 $1,500Machine Shop per Tuner 1 $5,000 $5,000Misc. 1 $5,000 $5,000Total per tuner cost $52,500

CAVITYNew ceramic windows 2 $10,000 $20,000New blocking capacitor 1 $13,750 $13,750New B+ choke 1 $2,500 $2,500New beam tube 1 $1,500 $1,500New mu tube 1 $1,000 $1,000New end plate assemblies 2 $1,000 $2,000New outer shell 1 $15,000 $15,000New inner conductor 1 $10,000 $10,000New gap electrodes 4 $500 $2,000New tuner 3 $52,500 $157,500Machine Shop per Cavity 1 $23,810 $23,810Misc 1 $10,000 $10,000

Total per cavity cost $259,060

Total for 21 cavities 21 $5,440,249.92Labor Cost Estimate is shown below

LABOR (in man-years) Estimate for Cavity & Tuner OnlyMechanical Engineer 1 $100,000 $100,000RF Engineer 1.5 $100,000 $150,000Drafting 1 $100,000 $100,000Technician 3 $100,000 $300,000

Total labor cost $650,000

Series Tube Modulator 20 90,000 1,800,000.00

6 Kwatt Solid State Wideband driver 20 100,000 2,000,000.00

200 Kwatt Power Amplifier 20 80,000 1,600,000.00 -

Installation 18 5,000 90,000.00

Total Excluding FNAL Labor 10,930,249.92

Summary:

• ~$260K per cavity, of which $160K goes for the three tuners.

• A roughly equal amount for the power supply chain.

• About 20 cavities.

-> $11M total

RF Upgrade: Questions to Answer

• Accuracy of the Cost Estimate?• Status:

– First prototype– Vacuum prototype– Design

• Reasonable timeline.• Ways to save money:

– Use old tuners?– Use existing power supplies?

• Ways in which universities can help:– Political pressure– Money– Fabrication

ORBUMP Project

• The current ORBUMP magnets can ramp at 7.5 Hz, with a substantial temperature rise.

• Need to go to 12 to support MiniBooNE and NuMI.• New design underway, but needs much more

attention.• Can new design incorporate injection improvements??

Simulation/Studies

• Any major improvement in the Booster will very likely involve at least some hardware improvements (in 30 years, every knob has been tuned).

• Any proposed hardware improvement will have to be supported by simulations and measurements.

• In a perfect world, we would be able to model the entire acceleration cycle of the Booster, and reproduce losses.

• We are probably years away from that.• We need to focus our efforts:

– Obtain the best lattice we can – including measurements!!– Do limited modeling studies to try to identify what are likely important factors in

instabilities:• Alignment??• Nonlinearities??• Aperiodicities??• Etc.

• There should be a much closer relationship between simulations and measurements.

Some General Comments

• The Proton Source CANNOT achieve its goals parasitically.

• The pressure from the collider program is not going to go away, so we have to come up with a plan to live together.

• We need, at the very least:– A commitment to a certain amount of dedicated study time

(few hours a week).– A commitment to priority on a console (preferably #2).

Conclusions

• We are at or near the present limit of the Booster output.

• This is a factor of up to ten away from what is needed.• Current plans might realistically increase things by a

factor of two or three, tops.• Getting further will be hard!!!