First Concepts for an Detector

DIS – Madrid, April 2009 1

First Concepts for an

Detector

E.C. Aschenauer


Requirements from Physicsep-physics

the detector needs to cover inclusive semi-inclusive exclusive reactions

large acceptance absolutely crucial particle identification (p,K,p,n) over wide momentum range excellent vertex resolution (charm) particle detection for very low scattering angle

uncertainty for e/p polarization measurements luminosity measurement uncertainty

eA-physicsrequirements very similar to ep

most challenging get information on recoiling heavy ion

from exclusive and diffractive reactions.

E.C. Aschenauer

Where do the electrons and quarks go


eRHIC vs. ELICMachine parameters crucial for a the detector

interaction rate ELIC: 500MHz a bunch every 2ns eRHIC: 13MHz a bunch every 70ns

e-beam current synchrotron rate ELIC: 0.55 A eRHIC: 0.26 A Hera: 0.050 A

IP design vacuum

E.C. Aschenauer


First ideas for a detector concept

E.C. Aschenauer

/ TRD

E.C. Aschenauer 6

Detector Magnetic Fieldby Tanja Horn, Rolf Ent and Richard Milner

Magnetic Field configration Solenoid is “easy” field, but not much field at small scattering

angles Toroid would give better field at small (~5 degrees) angles with

an asymmetric acceptance Improves acceptance for positive hadrons (outbending)

Improves detection of high Q2 electrons (inbending) Limits acceptance at very small angles (~3o) due to coils May limit acceptance for π+π- detection

Vary Solenoid field to see how far one can push and compare with toroidal field But … may not want too large a central solenoid field to access low-

momentum reaction products from e.g. open charm production (~0.5 GeV/c)

Could also add central toroidal or dipole field(s) to solenoid Small dipole component may be useful for lattice design (~0.3-0.5

Tm?) goal of dipole field on electron side to optimize resolutions goal of dipole field on hadron side to “peel” charged particles away

from beamEIC @ Berkley December08

E.C. Aschenauer 7

Simulation of Resolutions

EIC @ Berkley December08

Multiple scattering contribution:

Intrinsic contribution (first term):

..2cos0136.0

3.01

pp

lrT

nL

zB

4720

'3.0p

pp

2

nLB

r

T

• B=central field (T)

• σrφ=position resolution (m)

• L’=length of transverse path through field (m)

• N=number of measurements

• z = charge of particle

• L = total track length through detector (m)

• γ= angle of incidence w.r.t. normal of detector plane

• nr.l. = number of radiation lengths in detector

msc

intr

Assumptions: • circular detectors around interaction

point• nr.l. = 0.03 (from Hall D CDC)• all simulations done for pions !!!

“Easier” Solenoid Field – 2T vs. 4T?

• Intrinsic contribution ~ 1/B• Multiple scattering contribution ~ 1/B

p = 50 GeV p = 5 GeV

B=2T

B=4T

Include dipole field


As expected, substantially improves resolutions at small angles

E.C. Aschenauer 10

Beam Induced Detector Background


1) Beam particles-residual gas interactiona) Coulomb scattering b) Bermsstrahlung

2) Synchrotron radiationa) direct radiation generated in upstream magnets b) backward scattering from down stream components c) forward from mask tip and upstream vacuum chamber

3) Touschek Scatteringonly important for low energy colliders

4) Thermal Photon Compton Scatteringonly important for very high energy colliders

5) Beam-beam interaction6) Operational particle losses

Injection, machine tuning, beamloss, etc.

E.C. Aschenauer 11

What was seen at HERAPressure development


E.C. Aschenauer 12

What was seen at HERAPressure during Lumi Fill


E.C. Aschenauer 13

What was seen at HERAproton beam gas background



The RHIC Accelerator

E.C. Aschenauer

PHENIX

AGS

LINACBOOSTER

Pol. H- Source

Solenoid Partial Siberian Snake

200 MeV Polarimeter

Helical Partial Siberian Snake

Spin Rotators(longitudinal polarization)

Siberian Snakes

Spin Rotators(longitudinal polarization)

Strong AGS Snake

RHIC pC PolarimetersAbsolute Polarimeter (H jet)

STAR

AGS Polarimeters

Spin flipper

MEeIC4 GeVelectrons


MeRHIC at IR 2

E.C. Aschenauer

IR2 region: - asymmetric detector hall is very appropriate for asymmetric detector for e-p collisions - long wide (7.3m) tunnel on one side from the IR is good to place the ERLsDetector hall accommodates also the injector system (polarized gun, bunching system, pre-accelerator ERL) and the beam dump.Recirculation passes are going outside of the existing tunnel: warm magnets, acceptable synchrotron radiation power.

PolarizedElectron Source

Main ERLs; 6 cryomodules x 6 cavities x 18 Mev/cav = 0.65 MeV per linac

Recirculation passes:0.75, 2.05, 3.35 GeV

DX DX

4 GeV pass

0.1, 1.4, 2.7 GeV passes

D0, Q1,Q2,Q3

90 MeV ERL


IR2 Hall: Detector and Injector System

E.C. Aschenauer

Polarized gun200 keV DCwith combiner cavity

WienSpin rotator 5 (10) MeV

Linac

Bunching section

Beam Dump250 (500) kW

95 MeVERL

Soft bend0.05T, 1m

E.C. Aschenauer 17

Synchrotron Radiation into eRHIC IR


Two directions of synchrotron radiation in the eRHIC IR: Forward (direction of the electrons) generated by 10GeV electrons bent through a 0.2 Tesla detector integrated dipole magnet located 1m (from the magnet center to IP) upstream. Backward (opposite direction of the electrons) caused by the secondary radiation of the absorber located 7.2m downstream, (proportional to the primary radiation on the absorber.) In the current design, the fraction of the forward radiation fan hitting the absorber is 20% and 27%, generated in the magnets located 1m (from the magnet center to IP) upstream and downstream of the detector, respectively.

Number of Dipole Magnets at IP 2

Magnetic Field 0.2 TeslaMagnet Effective Length L 1.0 m

Electron Beam Current 0.5 A

Electron Relativistic Factor 1.96E+04Synchrotron Radiation Power P0 5.08 kW

Critical Photon Energy E0 13.3 keV

1. A horizontal hard bend and a vertical soft bend on both side of the detector;

2. The forward radiation from the up stream hard bend (red) is completely masked. No hard radiation passes through the detector;

3. The forward radiation from the up stream soft bend (blue) will pass through the detector without hitting detector wall.

4. The secondary backward radiation induced by the forward radiation generated in down stream bends will be largely masked from the detector;

5. The detector radiation background due to multiple scattering from the vacuum system, masks, collimators and absorbers will be investigated with computer simulations.

Forward Radiation Spectrum

Detector Synchrotron Radiation Background

The photon spectrum of forward synchrotron radiation:

P0 = synchrotron radiation power = electron relativistic factor (Ee

total/Eerest)

EC = the critical photon energyS-function defined as:

K5/3(z) = the modified Bessel function of the second kind.

)/()/(

20

2

C

C

C

SEP

dEdtnd

dzzKSCCC

)(8

39)(/ 3/5

p


Accelerator and detector integration and SR protection

E.C. Aschenauer

Solenoid (4T)

Dipole~3Tm

Dipole~3Tm

To provide effective SR protection:-soft bend (~0.05T) is used for final bending of electron beam-combination of vertical and horizontal bends

J.Beebe-Wang, C.Montag, B.Parker, D.Trbojevic


The ELIC Design

E.C. Aschenauer

The tunnel houses 3 rings:Electron ring up to 5 GeV/cIon ring up to 5 GeV/cSuperconductiong ion ring for up to 30 GeV/c

Medium

Ener

gy

IP

IP Magnet Layout and Beam Envelopes

IP 10cm 1.8m 20.8kG/c

m3m 12KG/cm

0.5m 3.2kG/cm

0.6m 2.55kG/c

m8.4cm

22.2 mrad 1.27 deg

0.2m

Vertical intercept4.5m

3.8m

14.4cm

16.2cm

Vertical intercept

22.9cmVertical

intercept

10.30

Thu Nov 29 23:19:38 2007 OptiM - MAIN: - D:\ELIC\InteractionRegion\IR\IR_ions_y.opt

0.5

0

10

Siz

e_X

[cm

]

Siz

e_Y

[cm

]

Ax_bet Ay_bet Ax_disp Ay_disp

ion5mm

10.30

Thu Nov 29 23:16:54 2007 OptiM - MAIN: - D:\ELIC\InteractionRegion\IR\IR_elect_y.opt

0.5

0

0.5

0

Siz

e_X

[cm

]

Siz

e_Y

[cm

]


4mm

electronN

β* OK

ELIC

ELIC: IR Final Quad

Optimization • IP configuration optimization• “Lambertson”-type final focusing quad• Crab crossing angle 22 mrad

IR Final Quad10 cm

14cm3cm

1.8m20.8kG/cm

4.6cm 8.6cm

Electron (10 GeV)

Proton (250 GeV)

2.4cm

10cm

2.4cm

3cm

4.8cm

1st SC focusing quad for ion

Synchrotron Power/Backgrounds

Synchrotron radiation in IR : lower electron energy than HERA!o Synchrotron Power ~ I E4 / Ro ELIC / HERA II current ratio: ~ 0.55 A / 0.045 A = 12o Electron energy ratio: (10 GeV / 27.5 GeV)4 = 0.017o ELIC / HERA radius: (0.18/1.0) = 0.18 1/R = 5.6o Use of crab crossing makes this simpler for IR:

Confirmed (C. Montag) for old 100 mr crab crossing case

o Detailed IR design needed

20 beam envelopes (green) and synchrotron radiation fans as generated by particles at 5 (red), horizontal (dispersive direction, x) to the left and vertical (y) to the right. The superconducting low- magnets are indicated in blue. This study is for 10 GeV electrons, 100 mr crab crossing angle, and 6m detector space. Current Design: crab crossing angle: 22mr, detector space: 8m

Alex Bogacz, Slava Derbenev, Lia Merminga (JLab)and Christoph Montag (BNL)

IR Synchroton Estimates – Cont.


Summary and A lot of work a head of us to come to from a detector sketch to a detector design

simulate golden physics channels in a detector frame start generic detector R&D

PID: High resolution / high rate ToF – systems high resolution 10 ps

Cerenkov radiators compined with modern light sensors

MCP-PMT, APD’s, SiPMT’s, HPD high rate 30ps – 80ps MRPCs 30kHz/cm2

Calorimetry:W-Si electromagnetic calorimeter / p0 separation Hybrid (StriPads) sensors with single- or double-sided readout

Developing Methods to tag Coherent Diffraction in e+A

Design Roman Pot stations, which would fit between DX-D0 magnets @ current RHIC measure in UPCs

E.C. Aschenauer

DIS – Madrid, April 2009 26E.C. Aschenauer

Backup

Lambertson Magnet Design

Magnetic field in cold yoke around electron

pass.

Cross section of quad with beam passing through

Paul Brindza

E.C. Aschenauer 28EIC @ Berkley December08

How should the detector look like

General requirements independent of EIC machine option

cover a wide range in Q2 detect scattered lepton ep and eA need good lepton-hadron separation

needed over a wide momentum range

Crab Crossing High repetition rate requires crab crossing to avoid

parasitic beam-beam interaction Crab cavities needed to restore head-on collision & avoid

luminosity reduction Minimizing crossing angle reduces crab cavity challenges

& required R&D

State-of-art: KEKB Squashed cell@TM110 Mode Crossing angle = 2 x 11 mrad Vkick=1.4 MV, Esp= 21 MV/m

p/p angular dependence

Can improve resolution at forward angles by offsetting IP


Multiple scattering contribution


Multiple scattering contribution dominant at small angles (due to BT term in denominator) and small momenta

Interaction Region: Simple Optics

Triplet based IR Optics• first FF quad 4 m from the IP • typical quad gradients ~ 12

Tesla/m for 5 GeV/c protons• beam size at FF quads, σRMS ~ 1.6

cm

Beta functions Beam envelopes (σRMS) for εN = 0.2 mm mrad

2

2max * 2 max *

*

( )

,

tripltripl

ss

ff

* = 14mm

┴* = 5mm

max ~ 9 km

8 m

f ~ 7 m 31.220

Mon Dec 01 12:26:08 2008 OptiM - MAIN: - N:\bogacz\Pelican\IR_ion_LR.opt

1200

00

50

BETA

_X&

Y[m

]

DIS

P_X&

Y[m

]BETA_X BETA_Y DISP_X DISP_Y

max ~ 9 km

┴* = 5mm

f ~ 7 m

8 m

31.220

Mon Dec 01 12:30:09 2008 OptiM - MAIN: - N:\bogacz\Pelican\IR_ion_LR.opt 2

0

20

Size

_X[c

m]

Size

_Y[c

m]


* = 14mm

Crab cavity development (~22 mrad crossing angle for 10 GeV electrons and 250 GeV ions)Electron: 1.2 MV – within state of art (KEK, single Cell, 1.8 MV)Ion: 24 MV (Integrated B field on axis 180G/4m)

Crab Crossing R&D program Understand gradient limit and packing factor Multi-cell SRF crab cavity design capable for high

current operation. Phase and amplitude stability requirements Beam dynamics study with crab crossing

ELIC R&D: Crab Crossing

Most electrons scatter at angles <25°, but Q2 > 1 GeV2 restricts to > 10° More forward angles correspond to (very) low Q2

Most electrons have few-10 GeV momentum Most pions electroproduced at forward angles > 140 degrees, even more

forward for higher ion beam energies Pions in “central” region, 25 – 140 degrees also have momentum of few-

10 GeV

P (G

eV)

Electron Lab Angle (deg)

Ee=5 GeVEp=50 GeV

Pion Lab Angle (deg)

Tanja Horn

H(e,e’π+)n – Electron & Pion Kinematics

First Concepts for an Detector

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