MAP MDI at SLAC

Thomas Markiewicz, SLAC Muon Collider Higgs Factory Workshop, UCLA March 22, 2013

Muon Accelerator Program (MAP) MDI

In 2013 SLAC submitted an MDI-focused work package to MAP mgmt. for funding Scope:

•  Concentrate on the Higgs Factory (1st) and 3 TeV collider (2nd) •  Develop a realistic implementation of a detector with IR magnets and local shielding •  Characterize performance

To better understand and control the background source terms, a small group of mostly volunteers has:

•  Acquired the current (preliminary) HF lattice •  Begun to study the lattice with rapid tracking tools: (Decay)Turtle, DIMAD & Transport

-  Uli Wienands & Lew Keller •  Created a FLUKA model of the lattice to understand “front end” issues of significance to

the detector: Takashi Maruyama -  Energy deposition in local masking, etc.

•  Communicate regularly with MAP MDI & Physics/Detector groups

Not yet begun •  Look at files of background in an SiD inspired detector in the LCSIM environment

-  Norman Graf et al 2

3

Introduction to Muon Colliders: First Principles

Input: •  Neuffer’s talk at MAP 2012 Winter meeting at SLAC •  Lattice: Alexahin (preliminary) v8.2

Muon lifetime = 1300 revolutions in 300m ring at 62.5 GeV Fill = 1000 turns= 1msec Fill frequency =15 Hz, 1 bunch/beam, 2E12 muons/bunch At injection

•  20 kJoules/beam, 300 kW/beam Decay electrons:

•  Peak decay rate = 5.1E6/m/beam •  Average electron energy in lab = 22 GeV •  Average electron angle in lab w.r.to muon = 1.7 mrad •  Peak e- power lost to ring = 5.4 MW/beam •  Average e- power lost to ring = 56.4 kW/beam •  Average e- power density =188 W/m/beam

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Decay Electron Kinematics

Elab (GeV)

Theta_lab (rad.)

Theta_lab (rad.)

Ela

b (G

eV)

Muon Collider Geometry in FLUKA Takashi Maruyama

Alexahin’s MAD deck •  Use MAD survey file

Wrote a program to read the survey file and generate FLUKA input.

•  Primitive geometry definitions •  Region definitions •  Material definitions •  Magnetic field type (bends, quads, sexts)

and strength Collider parameters are arbitrarily chosen, but can be changed easily.

•  Tunnel radius (2 m) •  Tunnel wall thickness (50 cm) •  Magnet shape and size (Bend: 2 m x 1 m) •  Beampipe thickness (1 mm) •  Beampipe radius (10 cm)

5

Steel

Concrete

Air

Dirt

Study #1 Backgrounds crossing scoring plane at 5m from source points

Scoring plane

- decays

Tunnel filling concrete shield added

6 Takashi Maruyama/SLAC

An example: Decays at z=22.7m without tunnel filling concrete shield

7 Takashi Maruyama/SLAC

Particle flux reaching the IR

10-2

10-1

100

101

102

103

104

105

106

107

Par

ticle

s / 5

mill

ion

deca

ys

3025201510

Distance from IP (m)

e- e+ photon neutron muon pion

8 Takashi Maruyama/SLAC

Decays at s = 6.4 m

X (cm)

Y (c

m)

e+/e-

X (cm)

Neutrons

9

Takashi Maruyama/SLAC

Tunnel

Decays at s = 22.7 m

X (cm)

Y (c

m)

Neutrons Muons

X (cm) 10

Takashi Maruyama/SLAC

- +

General Comments on background type & location

e+/e- and •  Inside beam pipe and magnet bore

Neutrons • Magnet bore • More diffuse over tunnel

Muons •  Bend magnets sweep muons and Magnet body acts like a

shield •  ~50 muons/meter

Hadrons •  Smaller flux and easier to shield

11 Takashi Maruyama/SLAC

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Study 2: IP Conic Mask Study Vary thickness at tip and look at particles penetrating the mask

•  Inspired by Mokhov 1.5 TeV design •  Use large apertures specified in Alexahin

lattice for IP magnets •  Maintain 6cm long beampipe at IP •  Scale beampipe radius to 4cm radius based

on 13.5cm to 1.78 cm radii of apertures of first quad in 1.5 TeV versus HF lattices

0

50

100

150

200

250

300

350

400

450

500

0 2000 4000 6000 8000 10000 12000

Masks  &  Final  Focus

M1_Cone

M1_Barrel

M2_Cone

QLB1

QLB2

QLB2

QLB3

Quad

r=22cm r=23cm

Quad Combined Function

IR Mask

Varied the thickness at tip from 5-75mm

2 × 107 decays between 0 and 4 m.

Count particles

3 Tesla Solenoid

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5E6 decays/m rate x 4m => results absolutely normalized Sig_x = Sig_y = 5cm at 1st quad

Takashi Maruyama/SLAC

Particle flux leaving beampipe and mask vs. Mask thickness

e+/e- 0.5 cm 1.5 cm 3.5 cm 7.5 cm

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e+/e

-/100

0/cm

Pho

tons

/100

0/cm

Takashi Maruyama/SLAC

Particle flux vs. Mask thickness

Neutrons 0.5 cm 1.5 cm 3.5 cm 7.5 cm

15

Neu

trons

/cm

Takashi Maruyama/SLAC

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Comments

Need a HF reference design with agreed to parameters: •  Emittances, beam sizes, etc. •  Beam pipe radii, apertures, VXD length, …

Designs too immature to invest vast computing resources (and time) •  Rapid prototyping tools & investigation of parameter space

preferable We at SLAC look forward to continuing this work if MAP

decides it is worth it