NBI March 2002 The MiniBooNE Horn Ioanis Kourbanis For The MiniBooNE Collaboration

NBI March 2002 Outline o List of people o Horn characteristics o Horn Power Supply o Horn Striplines o Highlights of Horn Construction and Assembly o Horn Testing o Horn Changeover o Future Plans

NBI March 2002 List of People C. Anderson L. Bartotzek (Bartoszek Engineering) L. Bartelson L. Bugel C. Jensen H. Le B. Markel (Markel & Associates) J. Misek F. Nezrick H. Pfeffer R. Reilly D. Snee M. Sorel E. Zimmerman

NBI March 2002 Horn Characteristics o We are using one horn with a narrow neck and a conical inner conductor (BNL Design) designed to run at a current of 170 KA. o The horn is made out of Al alloy 6061-T6 and is excited by a 143  sec current pulse. o Keep the voltage at the PS below 10 KV (use solid state SCR’s instead of thyristors) o Reduce the current pulse width as much as possible to avoid excessive heating of the horn. o Keep the voltage at the horn as low as possible (small inductance). o The horn will operate at an average rep rate of 5 Hz. Total average power deposited in the horn is 2.4 KW.

NBI March D Model of the Horn

NBI March 2002 Horn Power Supply p The Power Supply consists of a Capacitor bank (1,344  F) discharged through an inductive load by an SCR switch. The system has a separate circuit for energy recovery. p The circuit is divided into 16 parallel capacitors, each with its own SCR switch.

NBI March 2002 Horn PS Parameters

NBI March 2002 Power Supply Schematic

NBI March 2002 Power Supply View (Front)

NBI March 2002 Power Supply View (Back)

NBI March 2002 Horn Stripline o Balanced design (odd number of conductors) to minimize forces. o The conductor spacing is 1 inch. Fluted alumina insulators with a 2 inch creepage length were used to separate the conductors. o The test stripline piece, along with a clamped joint, were corona tested. o The inductance of the final stripline was measured to be 18.5 nH/m.

NBI March 2002 View of the Long Stripline Section

NBI March 2002 View of a Stripline Joint

NBI March 2002 View of the Small Stripline Section

NBI March 2002 Construction and Assembly Highlights p Forged Outer Conductor p The water sprayers were vibration isolated from the Horn Outer Conductor. p Solid connections from the striplines to the Horn. p The Horn Inner Conductor was welded at Fermilab using a programmable TIG welding machine.

NBI March 2002 Outer Conductor after Forging

NBI March 2002 Outer Conductor after Machining

NBI March 2002 Outer Conductor after Welding

NBI March 2002 Water Manifolds

NBI March 2002 Water Truss

NBI March 2002 Water Truss and Water Manifolds

NBI March 2002 Water Truss Bellows Detail

NBI March 2002 Water Connection Detail

NBI March 2002 Outer Conductor with Water Truss

NBI March 2002 Water Drain Connection

NBI March 2002 Water Nozzle Detail

NBI March 2002 Twist Transitions

NBI March 2002 Inner Conductor Before Welding

NBI March 2002 Hand Scraping before Welding

NBI March 2002 Welding Sample

NBI March 2002 Large Weld

NBI March 2002 Small Diameter Weld

NBI March 2002 Inspecting the Small Diameter Weld

NBI March 2002 Radiography of Weld

NBI March 2002 Radiography of Large Weld

NBI March 2002 Moving the Inner Conductor from The Welding Machine

NBI March 2002 Inserting the Inner into the Outer Conductor

NBI March 2002 Horn Testing p The horn was pulsed for the first time on 07/27/01. p The horn test was completed on 02/12/02 after completing 11M pulses at full current. p We completed horn magnetic field measurements. p Completed a series of vibration measurements. p Things we were monitoring: p Total current p Current in the four striplines feeding the horn p Total voltage p Cooling water supply and return temperatures p Horn temperatures

NBI March 2002 Overview of MI-8 Test Area

NBI March 2002 Horn module overview

NBI March 2002 Stripline Configuration at the TSB

NBI March 2002 Current and Voltage Profiles

NBI March 2002 Horn Magnetic Field Measurement

NBI March 2002 Horn Temperature Profiles with Different Sprayer Configurations

NBI March 2002 Correlation between Horn and Water Return Temperatures

NBI March 2002 Horn Vibration Spectrum

NBI March 2002 Horn Axial Displacement vs. Time

NBI March 2002 Horn Changeover p The horn module is expected to be highly radioactive (30 Rad/hr at 2 ft). p In order to reduce the Radiation Exposure to under 100 mR/hr at 1 ft, the shielding requirement is 5” of steel on all sides. p Because of the crane lifting capacity, two separate coffins (an inner and an outer ) will be used. p The inner coffin has 1.5’’ thick walls except from the top cover and the front door (5” thick). p The outer coffin has 3.5” thick walls and is open at the top and the front.

NBI March 2002 Horn Changeover (2) p The radioactive horn module will be stored inside the two coffins in the Target Service Building in the old Proton Line. p Four coffins (two inner and two outer coffins) will be needed for a changeover. p A detailed procedure outlining all the steps for a changeover has been written and reviewed. p Total estimated time for a changeover is 2 weeks.

NBI March 2002 Inner Coffin

NBI March 2002 Outer Coffin

NBI March 2002 Initial Configuration

NBI March 2002 Inner and Outer Coffins

NBI March 2002 Open Inner Coffin Door

NBI March 2002 Position the Coffins next to the Horn Module

NBI March 2002 Pull the Horn Module in the Coffin

NBI March 2002 Close Inner Coffin Door

NBI March 2002 Future Plans p We have started disassembling the Power Supply and the Striplines. p The horn modules will be stored in the inner coffin. p Plan to install the horn in the target pile on May 7. p We estimate to be ready for a horn changeover test on May 15. p We should be ready for beam on June 15. p We have started ordering the large pieces for a spare horn.