PS to 2010

What Will It Take to Have a Viable Proton Source through 2010?: 

What Will It Take to Have a Viable Proton Source through 2010? Elliott McCrory and Eric Prebys December 20, 2002

Outline: 

Outline Pre-Accelerator and Linac Elliott, et al. Vacuum tubes, power supplies, old equipment, personnel Booster Eric, et al. Activation, HL & LL RF, old equipment

Overview of Linac Concerns: 

Overview of Linac Concerns Pre-Accelerator Low Energy Linac Vacuum Tubes Especially the 7835 Power Amplifier triode LEL High Voltage Modulator F-1123 (switch tube) “QPS” power supplies Tank 1 High Energy Linac Radiation & Activation All fixes are Band-Aid patches Big $ & personnel outlay that is otherwise useless to the needs of the Laboratory further in the future

Pre-Accelerator: 

Pre-Accelerator Reliable operation is likely through 2010 Retirement of Hren and Wendt: 2015? No particular supplier problems Although we have had some interesting problems with the various components, e.g., power tubes. Will need to replace the Haefley HV supply with a better regulated model Line voltage variations are barely acceptable now.

Linac Vacuum Tube Docket: 

Linac Vacuum Tube Docket

The 7835 Power Triode: 

Very complex technology RF, material science, vacuum, chemistry Similar to other tubes made by Burle 4616 & 4617 7835 only used in the scientific community. One military user for 4617 Quality varies from decade to decade The 7835 Power Triode

Burle Industries, Lancaster, PA: 

Burle Industries, Lancaster, PA Enormous facility Makes all kinds of tubes Power tubes PMTs in competition with Hamamatsu Some picture tubes Was RCA Tube plant Radar tubes for AWACS

Histogram of Tube Lifetime: 

Total Tube Hours Average: 11726* Median: 11674* Sigma: 5522* *Removing outliers (Tank 1) Histogram of Tube Lifetime Updated 12/17/2002

Slide9: 

5 stations 9 stations Three tubes with >30000 hours excluded Updated 12/17/2002 In Service Now

Tube Throughput with Burle: 

Tube Throughput with Burle Median lifetime: 16 months Recent lifetime: Less! We need about 3.41 tubes/year to maintain Assuming historical median With present tubes: twice that. We have received 5 tubes in the last 12 months Including one borrowed from Argonne Expect 7 tubes over the next 12 months; next in February Burle now can make/rebuild ~20/year Critical path: Final bakeout; two stands, 3-5 weeks bakeout Also of concern: Supplier delivery time (e.g., ceramics, cathode) Delivery time: ~8 months, But, often 12 months!

Slide11: 

Ave: 6.8 Ave: 2.75 9 Sockets 5 Sockets

Why Would Burle Stop Making 7835s?: 

Why Would Burle Stop Making 7835s? If a supplier is not able to deliver raw materials ~1987: Thorium content of cathode dropped from 2% to 1.5% due to EPA issues at supplier Quality ceramics always hard to get If demand for 4616 tubes dries up E.g., our Switch Tubes (in modulator) Military still uses lots of these ~100s of these per year currently Burle’s “Bread & Butter” for this type of tube If life of tube is less than the delivery time! Tubes must last >>8 months in operation to be practical.

Alternatives?: 

Alternatives? To the 7835? None, really. This is the highest power 200 MHz tube in the world Los Alamos is looking into 3.5 MW “Diachrode” 201 MHz Klystron? Not likely! Pooling 7835s among the four US DOE Labs? BNL: 9 sockets, Argonne: 1, Los Alamos: 5, FNAL: 5

Summary: Will We Have Power Tubes in 2010?: 

Summary: Will We Have Power Tubes in 2010? Maybe, maybe not. Burle has every intention to make these tubes forever, but … Which “secondary” triode is going to stop being produced next??? What can we do now? Not much Use spare tubes from other labs

LEL High Voltage Modulator: 

LEL High Voltage Modulator Switch tubes are no longer made Military demand for F-1123 ended abruptly Triton closed the one remaining production line in 2002 We have 61 spares right now 2 y average life, 15 in service  replace 8 per year, 7 years left Econco may be able to rebuild these tubes 2010 is possible, but not much more. The clock is ticking!! 2020 is unlikely with this system What can we do now? New Modulator design

Low-energy End Quad PS: 

Low-energy End Quad PS 300 A, 200 V pulsed (15 Hz) power supply There are 116 supplies in service Largest inventory of PCBs on site Ancient technology Circuits rebuilt many times What can we do now? Decide on replacement technology and replace them, starting now

Ancient Technology: 

Ancient Technology Note Burn Marks

The Inside of a QPS Chassis: 

The Inside of a QPS Chassis Small PCB caps 10 PCB capacitors at 2 pounds each

7835 Filament Power Supplies: 

7835 Filament Power Supplies 7000A, 5VDC output (480VAC input) ~35KW just to light the filament. Hardware unreliable and hard to maintain One original spare exists (LRF6). Upgrade Controller Begun by Ma and Wahl One working new prototype at LRF7, but still needs minor interfacing work. PLC used is now obsolete; better units available but means more development work. 2010? Probable, with the controller upgrade This needs to be funded

O-rings on LEL Quadrupole Stems: 

O-rings on LEL Quadrupole Stems Have lost ~10 (aside from Tank 1) 16 years since the last failure When will they become too old to hold vacuum? Tank 5: More radiation exposure that ever 2010? January 2003 shutdown will give us information on the state of the o-rings now

Tank 1: 

Tank 1 Remember: This was a prototype! If we lose a quad in Tank 1 (e.g., to a short), it may take months to recover No post couplers—will be difficult to realign the quad and, simultaneously, stabilize the RF fields; Bead pull?! Continuous pumping on the stem box covers Some o-rings may be damaged Cannot regulate field w/changes in atmos. Pres. unless we pump 2010? With a little luck. O-rings and Tank 1: What can we do now? Nothing.

Other LEL Concerns: 

Other LEL Concerns LEL LLRF Should be relatively easy, inexpensive and interesting upgrade project Water Systems Upgrade underway now, should get us to 2010, but not 2020.

Radiation Concerns in the HEL: 

Radiation Concerns in the HEL Activation of components Delivering more beam than ever! And they want a lot more!! Areas at 100 mR/hr @ 1’, but component damage seems unlikely Hands-on maintenance may become problematic External shielding At ~50% of the trip point for some detectors outside of the tunnel Wire scan trips off the interlocked detectors quickly Significant improvement in reducing losses required, or Big redesign of the passive shielding

Number of Beam Pulses/Day: 

Number of Beam Pulses/Day 1.6 Hz

Other Concerns in the HEL: 

Other Concerns in the HEL What is the real lifetime of the klystrons? Will they all fail at once? Will need to send klystrons to Litton to keep their line active. Are there other components that are going to fail en mass? Obsolete LLRF computers Upgrade in planning stages now Need $$ for this upgrade HEL 2010? Will need to reassess external shielding Otherwise, no problems here

2010? Gambles: 

2010? Gambles Can we get enough 7835s? And will they last long enough? Will the supply of Switch Tubes be enough? Will Tank 1 break? Will the drift tube stem o-rings survive? Will radiation/activation become a problem?

2010? Specific Fixes: 

2010? Specific Fixes Haefley HV Supply Inter-lab spares for 7835 power tube Redesign the LEL Quad PSs Replace filament supply controllers Continue design effort for LEL modulator Replace the LLRF in the LEL Upgrade the computers in the HEL LLRF More shielding may be necessary at high-energy end Big $ & personnel outlay that is otherwise useless to the needs of the Laboratory further in the future

Beyond 2010?: 

Beyond 2010? Young’s proposal for new LEL Two ion sources and injector RFQs to ~1 MeV “Double alpha” injection into RFQ to ~7 MeV 400 MeV commercial drift tube Linac New, gentler transition section at ~70 MeV New 805 MHz SCCL module(s) to 116 MeV Price tag: ~$N x 107.

402 MHz Parameters from Young: 

402 MHz Parameters from Young Price tag: About $40 x 106.