MuCool Overview

NFMCC Meeting 3/12/06A. Bross

MuCool Overview

Muon Cooling R&DNFMCC MeetingMarch 12, 2006

A. Bross


MuCool

Consists of 9 institutions from the US and Japan

RF DevelopmentANLFermilabIITJLABLBNLMississippi

Absorber R&DFermilabIITKEKNIUMississippiOsaka

SolenoidsLBNLMississippi

Mission Design, prototype and test all cooling channel components

201 MHz RF Cavities, LH2 absorbers, SC solenoids Support MICE (cooling demonstration experiment) Perform high beam-power engineering test of cooling

section components


MuCool

R&D Focus of MuCool Component testing Fermilab

High Power–Both RF and Beam


MuCool Test Area

Facility to test all components of cooling channel (not a test of ionization cooling)

At high beam power Designed to accommodate full Linac Beam 1.6 X 1013

p/pulse @15 Hz – 2.4 X 1014 p/s– 600 W into 35 cm LH2 absorber @ 400

MeV RF power from Linac (201 and 805 MHz

test stands) Waveguides pipe power to MTA


MTA Hall


MTA

The MTA is the focus of our Activities

RF testing (805 and 201 MHz)

Installation/commissioning of Cryo-Infrastructure

High pressure H2 gas-filled RF

LH2 Absorber tests High Intensity Beam

Will start with low intensity


Towards Experimental Hall

Refrigerator RoomRefrigerator Room• Tevatron satellite refrigerator to be operated on 5 K mode and 14 K mode (3” DE, 3” WE)• Helium and nitrogen Dewar

Compressor RoomCompressor Room• Two 400 HP 2-stage oil injected screw compressors

Heat exchanger

MTA Cryo-Infrastruture

Compressor Installation and piping are complete

Needed forMagnet Operations

andLH2 Absorber Tests


MTA Cryo Infrastructure

Our goal was to have Cryo Plant Operational by NOW Needed signficant support from AD and PPD Cryo Groups

AD – Wet engine installation/Controls/Commissioning PPD – Transfer line system

But there was a problem Due to resource allocation to ILC cryo work, completing

the MTA Cryo by end of March did not happen Negotiations with the Lab are in progess

Start installation effort again in earnest after shutdown cryo work is completed

New goal is to be operational late Fall Running off 500L LHe dewars will cost the collaboration

approximately $3-4k/week of magnet operation Expensive! – Working to optimize system for most efficient use

of LHe


MTA High Intensity Beam

MTA

400 MeV beamline for the MTA has been designed

Under Craig Moore/Carol Johnstone

External Beams Department Developed Engineering Design

Cost Schedule

Safety Analysis Linac Area and Beamline Shielding Assessment for MTA

The current beam line design allows for Linac diagnostic

High-Quality emittance measurement

Our goal is to bring Low Intensity to the MTA as soon as possible


Proceeding with the MTA Beam Line

Cost Estimate: $388k (including 30% contingency) Low-Intensity initial phase

Resources: $100k from Muon Collaboration Requests

PPD Pulsed Extraction Magnets: $75k in FY06 M&S (not likely at present) Magnet stand fab

AD – SWF for installation Internal AD review November 30th. The response from the committee

was positive, but they asked a number of questions. A response to these questions has been prepared has submitted.

Review Committee’s final report:– It was agreed that the basic design philosophy is sound, and that the

diagnostic section will be of great use not only to the MTA, but to the general Linac operation as well. Assuming that the items in the above list are addressed, and that doing so identifies no new issues, then the committee can fully support the MTA beam line design.

Modifications in Linac area have just been completed Isolates future MTA beam line work from Linac operations


MTA – Near Term Test Program

805 MHz Pill Box preparation complete11/30/05 Low power testing and conditioning begins

Currently have reached approximately 1MV/m 805 MHz high-power testing begins 1/1/06

TiN coated curved Be windows tests Various B field configurations

201 MHz cavity testing begun 3/06 Major Milestone has been reached

LH2 Absorber test Summer 06 Second phase of testing with KEK convective absorber This is dependent on new safety review


RF Cavity R and D

ANL/FNAL/IIT/LBNL/UMiss


Fundamental Focus Of RF R&D

Study the limits on Accelerating Gradient in NCRF cavities in magnetic field

However We believe that the behavior

of RF systems in general can be accurately described (predicted) by

Tensile strength of the material(s) used in the cavity fabrication (T)

Local surface field enhancements (eq)

Esurf = 2T//eq

This applies to all accelerating structures

In SC structures local heating becomes problem first

Follows universal curve


Phase I of RF Cavity Closed Cell Magnetic Field Studies (805 MHz)

Data seem to follow universal curve

Max stable gradient degrades quickly with B field

Sparking limits max gradient

Copper surfaces the problem

Gra

dien

t in

MV/

m

Peak Magnetic Field in T at the Window


Phase II of 805 MHz studies

Study breakdown and dark current characteristics as function of gradient and applied B field in Pillbox cavity

Curved Be window Test TiN coated Cavity has been

conditioned to 32MV/m without B field

Measurements at 2.5T– So Far – stable

gradient limited to about 14MV/m

Button test Evaluate various

materials and coatings Quick Change over


RF R&D – 201 MHz Cavity Design

The 201 MHz Cavity is now operating Recently reached 16MV/m at B=0! (design gradient)


Local Electrode Atom Probe (LEAP) Tomography

Atom probe experiments in collaboration with Northwestern U.Prof. David Seidman Jason Sebastian (Northwestern),P. Bauer, C. Boffo (FNAL), J. Norem (ANL)

High Gradient material studies relevant to both NCRF and SCRF – ILC, Neutrino Factory, Muon Collider, CLIC.

Surface microstructure Surface contamination (oxides etc.) Breakdown and Dark Currents

Data from these tests expand our knowledge of breakdown phenomena, will allow us to develop a detailed model of the physics of breakdown in cavities, and can provide a guide for materials/fabrication procedures for RF cavities

Atom Probe Data from Nb sample @ ~10 GV/m Modeling Fracture


High Pressure H2 Filled Cavity WorkMuon’s Inc

High Pressure Test Cell Study breakdown properties

of materials in H2 In B field next


Absorber R and D

IIT/KEK/NIU/Osaka/UMiss


2D Transverse Cooling

and

Figure of merit: M=LRdE/dsM2 (4D cooling) for different absorbers

Absorber Design Issues

Absorber Accelerator Momentum loss is opposite to motion, p, p x , p y , E decrease

Momentum gain is purely longitudinal

Large emittance

Small emittance

H2 is clearly Best -Neglecting Engineering

Issues Windows, Safety


Absorber Design Issues

Design Criteria High Power Handling

Study II – few 100 W to 1 KW with “upgraded” (4MW) proton driver

10 KW in ring cooler– Must remove heat

Safety issues regarding use of LH2 (or gaseous H2)

Window design paramount– H2 containment

Proximity to RF adds constraints (ignition source)

Two Design Approaches Convective Cooling

– Shown to the right Forced flow

– High power handlingH2 implies engineering complexity


Convective Absorber Activities

First Round of studies of the KEK absorber performed in the MTA

GHe used to input power


Convective Absorber Activities II


Convective Absorber Activities III

Next Round of tests will use a modified absorber

Test Electrical Heater New

Temperature sensors

LH liquid level sensor

Absorber Body being modified in Lab 6 at Fermilab


Forced-Flow Absorber Heat removed with external heat exchanger

LH2 pumped from absorber to heat exchanger Nozzles in flow path establish turbulent flow Simulation via 2D and 3D FEA

Preliminary engineering design for implementation in the MTA Have taken possession of cooling loop & heat exchanger from SAMPLE

experiment @ Bates/MIT Prototype Absorber manifold has been fabricated


MuCool Plans for the Coming Year

After a long pause due to the loss of our 805 MHz RF test facility in Lab G at Fermilab, we are now up and running again

805 MHz RF studies (with and without B field) Be Window tests Materials tests Surface treatment Use information from LEAP studies

201 MHz RF test program off to a Rousing start! B field tests Curved Be Windows

Second round of tests with KEK convective absorber IIT ME thesis student to work on flow-absorber

simulation and test Complete MTA cryo infrastructure installation and

commission system Continue installation of 400 MeV beam line from Linac to

the extent that resources allow Have the capability for low-intensity experiments

RFHighest Priority!


The MuCool Test Area Potential

The MuCooL Test Area is becoming a tremendous resource It has the potential to provide a Unique

(World-wide) R&D facility Multi-frequency RF test capability (NC and SC) Hydrogen Safety

– Absorbers– Gas-filled RF cavities

Cryo-infrastructure (LN, high capacity LHe) High-Intensity beam

MuCool Overview

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