h. haseroth friday, august 31, 2001 mug meeting 1 overview of the cern neutrino factory machine...

H. HaserothFriday, August 31, 2001

MUG Meeting1

Overview of the CERN Neutrino Factory Machine Studies

H. Haserothfor the

Neutrino Factory Working Group


MUG Meeting2

The Basic Concept of ANeutrino Factory

Proton driver High-power proton beam onto a targetSystem for collection of the produced pions and their decay products, the muons.Energy spread and transverse emittance have to be reduced: “phase rotation” and ionisation coolingAcceleration of the muon beam with a linac and “RLAs” (Recirculating Linear Accelerators) Muons are injected into a storage ring (decay ring), where they decay in long straight sections in order to deliver the desired neutrino beams.


MUG Meeting3

Goal: 10E21 muons/year


MUG Meeting4

The original idea as expressed by Kurt had the goal of having ready two future options for CERN at the time when LHC is running: CLIC and the Neutrino Factory.

CLIC had been started much earlier and with this argument a distribution of R&D resources of 1/3 for the NF and 2/3 for CLIC has been justified.

Formally we are not too far away from the 1/2 ratio (of course we are lower!). It must, however, be remembered - especially when we are compared to the US - that in our case the proton driver (SPL and accumulator / compressor rings) is counted as "NF activity". The proton driver is a substantial element in our CERN scenario. In the US this is not really counted as NF activity, but as a mere and simple upgrade of their existing machines.


MUG Meeting5

Activities concerning the Proton Driver(Main CERN Actors with substantial fraction of their time)

SPL (Garoby, Lombardi, Vretenar)

Accumulator Ring (Schonauer, Metral, Cappi)

Compressor Ring (Schonauer, Metral, Cappi)

Fast cycling Synchrotrons (Schonauer)


MUG Meeting6

Schematic Layout of the SPL(4 MW of Beam Power)


MUG Meeting7

The SPL on the CERN site


MUG Meeting8

- 150 - 100 - 50 50 100 150z

50

100

150

200

250

300

x

RAL Accumulator (1)

ISR tunnel

2.2 GeV RAL Accumulator

Mean ring radius=150 m


MUG Meeting9

RAL Accumulator & CERN Compressor (2)

Accumulator & Compressor

Accumulator

Compressor

in ISR Tunnel


MUG Meeting10

33 Hz Operation with 3.41 1014 p/p : End of Compression (Phase painting +/- 90 deg)

8 turns 10 turns


MUG Meeting11

Non Proton Driver Activities(Main CERN Actors with substantial fraction of their time)Target and collection (magnetic horn) work, i.e. simulations of pion production, simulations of capture and experimental work on target issues (Ravn, Lettry, Volker, Maugain)

Simulation of the phase rotation (energy reduction), of the cooling channel and of the acceleration in the first linac (Lombardi, Hanke, Holzer)

Simulation the RLAs (Recirculating Linear Accelerators) and of the Decay Ring (Keil, Verdier)

Work by ST for layout on the site (Poehler)

Detector locations being investigated (Wenninger)


MUG Meeting12


MUG Meeting13


MUG Meeting14

Ideally a muon is stopped by passing through some material and is being accelerated in the forward direction.

Because it would have decayed in the meantime, only some reduction in longitudinal and transverse momentum is applied. The longitudinal momentum is being replaced again by RF acceleration.

Problem: Heating because of multiple scattering.

Principle of Ionisation Cooling


MUG Meeting15

p

t

Why a compressor ring? Why bunch rotation?(146 bunches during 3.3s)

Pions(used)

10 ns

1 ns 10 ns10 ns

Protons inaccumulator

Pionswasted

Pions(used)

Protons aftercompressor

Pions after target

Muons afterdrift

Muons afterphase rotation

1 ns

Works only if < 1

Works only if 1

(RF gradients)


MUG Meeting16

Asymmetric 88 MHz cavities


MUG Meeting17

Layout of 40/80 MHz Cooling Channelbeam in

beam out


MUG Meeting18

Parameters of Recirculating Linacs (RLAs)

Parameters of Decay Ring


MUG Meeting19

Preliminary Layout of Neutrino Factory


MUG Meeting20


MUG Meeting21

Arguments for an International Muon Cooling Experimental Demonstration

There are quite different opinions about the necessity to do a cooling experiment, however, the majority believes strongly that there is a need to demonstrate that ionisation cooling is indeed technically feasible. Some people feel that even the relevant programs need checking by experiments. One remark to answer criticism like "we know Moliere scattering and Maxwell's laws" is that in spite of knowing Maxwell's laws and the properties of superconducting cable one has built not only one but several magnet prototypes for the LHC. Muon ionisation cooling is by no means more trivial.

As a by-product of the discussions in the context of the cooling experiment several new ideas came already up, which were the result of stimulating exchange of ideas, not limited to the SPL and the target:

The idea of "Beta - beams", i.e production of neutrino beams by decay of radioactive isotopesVery important findings about the H2 absorber heat load due to electron beams from the cavities.


MUG Meeting22

A possible (poor man's ) Muon Cooling Experiment

The main hardware is composed of the following items:

RF cavities RF transmitters, modulators and charging supplies Cavity sc solenoids Hydrogen absorbers Measuring lines at input and output including sc solenoids and data acquisition


MUG Meeting23


MUG Meeting24

To minimise the cost, the following distribution of hardware contributions is envisaged (very personal and provisional!):

1) One 4 cell cavity from the US collaboration (LBNL)2) CERN (One rf transmitter refurbished with pieces from Linac1, one spare borrowed. Upgrading of power with special tube (old 516) needed. Russian manpower is sought to help)3) Swiss confederation, RAL, EU money?4) American / Japanese collaboration (IIT et al.)5) Collaboration of different physics institutes (V. Palladino)

+ a Muon Beam (PSI or RAL)


MUG Meeting25

Cooling experiment at PSI?

h. haseroth friday, august 31, 2001 mug meeting 1 overview of the cern neutrino factory machine...

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