By the Target Working Group Presented by L.Bruno AB/ATB Targets & Dumps Section

7-11 November 2003 NBI 2003 – CNGS Target StationPresentation by L.Bruno (CERN AB/ATB) 1

By the Target Working Group

Presented by L.BrunoAB/ATB Targets & Dumps Section

The CNGS Target Station

Technical Study


The CNGS Target Station

OUTLINE

1. Introduction 2. Shielding 3. Target Unit

4. Structural issues 5. Summary


Introduction (that is, what I will say and what I will NOT…)

Subjects covered in previous workshops

Driving parameters Conceptual design philosophy Target configuration and optimization

Subjects covered in THIS workshop Engineering design of the shielding Engineering design of the target New issues and developments


Layout - Vertical view

Target enclosure

Shield

Crane limit

Horn

lim

it

Horiz. Base plane

Target assembly

Steel frame

Proton beam

Fixed structure “Handled” structure


Layout - Front view

Passage

side

Cavern side

Target enclosure800x1400x3200 mm3

marb

le

Sid

e w

all

No access

Cap

Sid

e w

all

Sid

e w

all

Base

Iron shield

Proton beam


Target handling

Alignment table

Fiducials

Beam

Base table

Unit exchang

e mechani

sm

Collimator

BPKG monitor


Mobile shielding cap

Flat railGuiding rail

Passage

side

Cavern side

Manual Coupling

Quick disconne

ct


Mobile shielding – Top view

JacksBeam

Threaded shafts

Rail sections

Motor

Switches

Rail transition

Target magazin

e

BP

KG

C

ollim

ato

r


CouplingHorizontal

Motor

Beam

Slope 0.5%

Mobile shielding – Side view


Target AlignmentCourtesy of D.Missiaen

Passage

side

Cavern side

No access

Base

Proton beam

Alignment is based on: 2 horizontal bars for :

transversal alignment raw vertical alignment

2 vertical back-up bars used for accurate vertical alignment

Bars are: removable equipped with fiducials equipped with

clinometer ~1.2÷1.8 m long inclin. < 0.05/5 mrad

(H/V) provided with an

horizontalization system


Alignment by the horizontal bars Courtesy of D.Missiaen

Vertical measurementsperformed by means of an optical level using a deep reference and/or the adjacent components. Accuracy is not better than 0.15mm because of the bar inclination.

Horizontal measurementsDone by a motorized tacheometer driven by a PC. The operator is far from the area. Accuracy is in the range of 0.1 mm. The operator has to install and level the bar in a radioactive area (short time).

Note: vertical measurements can be improved to better that 0.1 mm accuracy by using the vertical bars. Access to the radioactive top shielding is restricted to long shut-downs

PC-driven tacheomete

r


Target handling

Alignment table

Fiducials

Beam

Base table

Unit exchang

e mechani

sm

Collimator

BPKG monitor


Target unit

DownstreamWindow

Target Support

Sealed finned tube

Inert gas

End cap

End cap

UpstreamWindo

w

The target unit is conceived as a static sealed system filled with inert gas. The tube has annular fins to enhance convective heat transfer. Light materials are used to limit the heat load.

MATERIALS

Tube: Al-Mg alloyWindows: Be by Brush & WellmanTarget Support: Carbon Fiber reinforced CarbonTarget rod: Fine-grain graphite

hexagonal boron nitride, CFC

Central tu

be


Unit Windows

St.Steel Aluminium alloy 5083

EB weld

B&W Be

window

(Ø1.5”)

B&W Be

window

(Ø4”)

Be-Al joint

Beam


Upstream end cap

Inner support

C-C Support Structure

“Pinch-off”

Helicoflex


Central Tube

Inner supports

A-A B-B

A-A B-B

Outer suppo

rt

Outer suppo

rt

Reference

surface


Carbon Support Structure

Traversing rod supports

Inner supports

Cooling apertures

Common ref.

surface


Target elements – a new issue

New additional studies performed by an analytical model point out that…

If the target unit is cold (start-up)… and a first proton spill of ultimate intensity… hits the target with the worst misalignment… followed by a second, similarly misaligned spill… and stresses add up in the worst way ,

Then…


Maximum total stress [MPa]in a 2020PT graphite target rod

… unacceptable stresses are found


Target Material

hBN

0

13

26

39

52

65

78

0 200 400 600 800 1000

Temperature [°C]

Yo

un

g M

. [

GP

a]

/

σ

t [M

Pa]

-1

0

1

2

3

4

5

Cp

[kJ/

kg°C

]

α

[µm

/m °

C]

α┴

cp

E

σ4P

α||

Graphite

0

13

26

39

52

65

78

0 200 400 600 800 1000

Temperature [°C]

Yo

un

g M

. [

GP

a]

/

σ

t [M

Pa]

-1

0

1

2

3

4

5

Cp

[kJ/

kg°C

]

α

[µm

/m °

C]

α

cp

E

σ4P


Summary

Status in November 2003

1. The detailed design of the target station is being worked out;

2. The choice of the alignment procedure is being finalized;

3. The target assembly is being optimized (manufacturing, integration,…)

4. The interfaces for handling, cooling, beam instrumentation and alignment are being defined.

5. The worst-case stresses are presently an issue.


Twg TwgTwg

1st R

evie

w

Installation

Manufacturing

Technical study

Engineering study

2n

d R

evie

w

Conceptual design

Planning overview

2001 2002 2003 2004 2005


Target element

Documents

By the Target Working Group Presented by L.Bruno AB/ATB Targets & Dumps Section