RECENT RADIATION STUDIES ON THE BDIR, DUMPS, LINAC AND TEST FACILITIES

ILC BDS MeetingJune 30, 2006

FermilabEnergy Deposition/Accelerator

Physics

Nikolai Mokhov

Noriaki Nakao

Sergei Striganov

Fermilab

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 2

OUTLINE

1. BDS, Extraction and Beam Dumps 2. Backgrounds in SiD Detector3. Bent Crystals at ATF2 and

Tevatron4. SMTF Test Facility5. Main Linac Cryomodule6. NIU Beam Diagnostics Laboratory

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 3

Thorough Modeling of BDS Collimation & Extraction

• Synchrotron radiation and performance of collimation and extraction

systems (STRUCT, A. Drozhdin and X. Yang).

• Simulations and benchmarking of collimation system with BDSIM, MARS15 and STRUCT (with UK and SLAC colleagues).

• Model refinement and further simulations of radiation loads and radiation environment in BDS, IP and extraction (MARS15).

• Masks and extraction beam dumps (MARS15).

Consider marble on most collimators

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 4

Water and Liquid Sodium Dumps

T1/2 (yr) Sat. time (yrs=5000hr)

TBq TBq

3H 12.35 93 146 258

7Be 0.146 1.1 60 63

Water Sodium

TBq TBq3H 237 202

7Be 58 1922Na - 442

Verification for 250-GeV 12-MW e-beam on water dump (R=0.6m, L=10m)

TESLA TDR MARS15

250-GeV 11-MW e-beam on water and sodium dumps (MARS15)

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 5

Muon Spoilers in BDS Tunnel

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 6

BDS Background in SiD

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 7

IP & BDS Backgrounds in SiD

STRUCT + MARS15 + SLIC+ LCDD + PYTHIA

HCAL Endcap hit rates:

Red – BDS (no spoilers)Green – BDS (w/spoilers)Blue – e+e- events

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 8

Bent Crystal Experiment at ATF2

• On June 1, 2006, ATF-TB has accepted the proposal to set up a bent crystal at ATF beam dump

• They want us to estimate radiation when the beam hits our setup from the radiation safety point of view

• We need an estimate by next ATF-IB meeting in Vancouver in July

• Simulations will be performed with MARS15 at Fermilab and (hopefully) with GEANT4 at Hiroshima University

• KEK and Hiroshima team will come to Fermilab for crystal collimation

experiments at Tevatron in November-December

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 9

Beam Dump and Beam Loss in SMTF Test Facility

750-MeV 45-kW e-beam on dump

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 10

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 11

Cryomodule MARS15 Model

Nb(cavity)

mu-metal

Ti

SS(Stainless Steel)

SSSS

SS Al

Al

Si(thermister)

Si(thermister)

Al

Al

Carbon Steel

He-gas

He-Liquid

thermal shield

thermal shield

Radiation loads totemperaturesensors

Ductstreamingthroughwaveguidesin Linac

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 12

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 13

Cryomodule Geometry in MARS15

Nb(cavity)

mu- metal

SS(Stainless Steel)

SS

AlAlCarbon Steel

He-gas

mu- metal

Ti

Nb(cavity)

Test calculation 100 MeV electron 1E12 e/sec (16W) 1mrad uniform loss inside cavity

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 14

Prompt Dose Rate

Prompt Dose [mSv/ h] Prompt Dose [mSv/ h]

Side View(Integrated over diameter length)

Front View(Integrated over 12 m long)

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 15

Power Density , Energy deposition [Gy/ sec, mW/ g]

Si(thermister)

Si(thermister)

Absorbed Dose Rates in Thermisters

Up to 0.2 Gy/s,with 100-MeV16-W beam loss

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 16

Needed Parameters

Source TermPower?Distributions of energy, angle, location?

for - Beam halo - Dark Current Fowler-Nordheim Model (TESLA Report 2003-10) Simplified source term?

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 17

Shielding and Maze Design for NIUILC Beam Diagnostics Laboratory

• R&D on charged particle beam diagnostics for ILC (ILCTA at Fermilab, AWA at Argonne), FEL, proton driver

• Ultimate goal: Operate a low-average-current, 6-20 MeV racetrack-microtron accelerator to drive coherent

light source

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 18

Basic Beamline Design atBeam Diagnostic Laboratory

<Beam Parameter>

6~20 MeV10 A in peak6uA in average

Bunch 0.44 nC 10-20ps(total) 2.856 GHzPulse 1 Hz

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 19

Shielding Structure at BDL

?

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 20

MARS15 Geometry

2 feet thick concrete Shiedling

Al beam dumpwith Lead Shielding

Electron Gun

Beam line

20 MeV6 uAelectron beam

20 MeV6 uAelectron beam

Lead Shielding

Al beam stopper1cm thick

1'

2' diam

1'

ILC BDS – June 27, 2006 Radiation Studies - N. Mokhov, N. Nakao, S. Striganov 21

Prompt Dose with MARS15

P rompt D ose [mrem/ h]

Side view

100

DOE regulation:

Prompt Dose Rate < 1mrem/hr - Outside concrete shielding wall - Exit of Maze

Should Review dump & wall design

Analytical approach + MARS15

50

T op view

10

10

100

50