replacement of bqks in ip4 by high bandwidth bpms in ip4 ...€¦ · in table 1, we also indicate...

EDMS NO. REV. VALIDITY

0000000 0.1 DRAFT

REFERENCE

LHC-BPW-EC-0001

Date: 2018-07-26

Note: When approved, an Engineering Change Request becomes an Engineering Change Order.

This document is uncontrolled when printed. Check the EDMS to verify that this is the correct version before use.

CERN CH-1211 Geneva 23 Switzerland

LHC

ENGINEERING CHANGE REQUEST

Replacement of BQKs in IP4 by High

Bandwidth BPMs in IP4 for HL-LHC, and

Installation of a Prototype during LS2 BRIEF DESCRIPTION OF THE PROPOSED CHANGE(S):

New high bandwidth Beam Position Monitors will be required in IP4 for beam crabbing

observation post LS3. According to optics simulations, possible locations, i.e. with an

adequate phase advance to observe beam crabbing from IP1/5, have been identified

respectively close to Q5 and Q6 where the BQKs sit today. It is then proposed to replace

these long pick-ups (BQKs) by new high bandwidth monitors.

The installation of a prototype monitor is also foreseen during LS2 and will replace the

existing BQKH.L4.B1.

DOCUMENT PREPARED BY: DOCUMENT TO BE CHECKED BY: DOCUMENT TO BE APPROVED BY:

T. Levens (BE-BI)

T. Lefevre (BE-BI)

C. Adorisio, M. Barberan,

I. Bejar Alonso, M. Bernardini,

J. Blanc, G. Bregliozzi,

S. Bustamante, R. Calaga,

JP. Corso, S. Costa Machado,

R. De Maria, P. Fessia, R. Folch,

JF. Fuchs, C. Gaignant,

M. Giovannozzi, B. Holzer,

E. Jensen, R. Jones, M. Lamont,

Y. Muttoni, T. Otto, E. Page,

S. Redaelli, D. Ricci, G. Riddone,

R. Steerenberg, M. Tavlet,

R. Veness, J Wenninger,

M. Zerlauth

P. Collier

(on behalf of LMC)

L. Rossi

(on behalf of the HL-LHC project)

DOCUMENT SENT FOR INFORMATION TO:

ATS group leaders

SUMMARY OF THE ACTIONS TO BE UNDERTAKEN:

Space reservation for new pick-ups for crab cavity observation (installation foreseen during LS3)

Installation of new beam position monitor between Q5 on the left side of IP4 during LS2.

Pulling additional optical fibres will be required.

REFERENCE EDMS NO. REV. VALIDITY

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1. EXISTING SITUATION AND INTRODUCTION

The use of crab cavities in the HL-LHC era would require high-bandwidth beam position

monitors to measure the beam crabbing. Those monitors must have a fast time response

in the 20-50 ps range to be able to measure the intra-bunch beam position. They would

also need to be located at a position with a phase advance as close as possible to 90

degrees with respect to the position of the crab cavities in IP1/5 (or 0 degree with

respect to IPs). In order to observe beam crabbing from both beams in H and V, we

would need 4 new pick-ups to be installed in LSS4 during LS3.

A prototype of such a pick-up is proposed to be installed during LS2, replacing the

BQKH.L4.B1.

Identifier 11599 (re-opened after the closure of the initial request 10627) in the PLAN

tool references this activity.

2. REASON FOR THE CHANGE

The current head-tail monitors, installed on BPLH.6R4.B2 and BPLV.6R4.B1 beside Q5R

and BPLH.7R4.B1 and BPLV.7R4.B2 beside Q6R, can already reach a time resolution

close to what is required for crab cavity monitoring. However, they are not installed at

a location with an optimised phase advance. Based on beam optic simulation for HL-

LHC, a total of 4 monitors will be needed to be able to measure beam crabbing from

IP1/5 in both the horizontal and vertical planes. We propose for HL-LHC to replace the

existing BQKs, which are located at those positions today and have never been used

operationally, by new pick-ups capable of providing the best possible time resolution for

crab cavity diagnostics. A prototype is proposed to be installed during LS2 as a

replacement of the BQKH.L4.B1.

3. DETAILED DESCRIPTION

The phase advances in Q5 and Q6 at IP4 with respect to IP1/5 have been simulated for

the case of HL-LHC and are shown in Figure 1.

Figure 1 — Optics simulation showing the phase advance in H and V with respect to IP1/5 for both

beams in the case of Hl-LHC baseline optic scenario.+


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As an indication extracted from Figure 1, we present in Table 1, a figure of merit of the

sensitivity of a pick-up located at the close vicinity of Q5 and Q6 to beam crabbing in

IP1/5 in both the horizontal and vertical planes. ‘Green’ means a phase advance close

to 0 degree, thus capable to measure beam crabbing with a good sensitivity. ‘Orange’

represents phase advances of 25-50 degrees, which are not fully optimized to measure

beam crabbing. And ‘Red’ is corresponding to phase advances close to 90 degrees which

are unsensitive to beam crabbing.

Table 1 — Phase advance for IP1/5 in the Horizontal and Vertical planes

Q5 Q6

IP1Y B1 BQKV.L4 – B1 BQKH.L4 – B1

IP1Y B2 BQKH.R4 – B2 BQKV.R4 – B2

IP5X B1 BQKV.L4 – B1 BQKH.L4 – B1

IP5X B2 BQKH.R4 – B2 BQKV.R4 – B2

IP1X B1 BQKV.L4 – B1 BQKH.L4 – B1

IP1X B2 BQKH.R4 – B2 BQKV.R4 – B2

IP5Y B1 BQKV.L4 – B1 BQKH.L4 – B1

IP5Y B2 BQKH.R4 – B2 BQKV.R4 – B2

In Table 1, we also indicate the name of existing stripline pick-ups, named BQKs,

installed close to Q5 and Q6 respectively on the left and on the right sides of IP4. These

pick-ups can be found in

Figure 2 andFigure 3 in the current machine layout on the left and the right side of IP4

respectively.


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Figure 2 — Current LHC layout in IP4 left.

Figure 3 — Current LHC layout in IP4 right.


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One should note that all existing BKQs have cables, 2x 7/8” coaxial cables and 1x 26-

pin control cable, that will be reuse for signal acquisition and control. They are currently

coming from the pick-up to the racks BY06=UA47 and BY11-UA43 respectively on the

right and left side of IP4.

For HL-LHC, we propose to replace those BQKs with dual plane high-bandwidth pick-ups

for crab-cavity diagnostics. The new layouts in IP4 for HL-LHC, where the BQKs have

been replaced by space reservation zones, are shown on Figure 4 and Figure 5 for the

left of right sides of IP4 respectively.

Figure 4 — HL-LHC layout in IP4 left.


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Figure 5 — HL-LHC layout in IP4 right.

During LS2, we propose to replace the BQKH.L4.B1 by a high bandwidth BPM prototype.

The design of this pick-up is under study at the moment such that we cannot provide

more detail on its integration. However, the installation will be made such that the

BQKH.L4.B1 will be replaced one to one by the new monitor and its mechanical support

will reuse the existing support of the current stripline.

This new pick-up is based on the use of fibre laser and would require the pulling of new

fibres (4 polarisation maintaining fibres and 4 single mode fibres). The existing cables

will be reused for signal acquisition and control. The laser system and the optical

detection system will be rack-mounted in BY11=UA43.

4. IMPACT ON OTHER ITEMS

4.1 IMPACT ON ITEMS/SYSTEMS

BQKH.L4.B1 New pick-up with a modified support

4.2 IMPACT ON UTILITIES AND SERVICES

Raw water: no

Demineralized water: no


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Compressed air: no

Electricity, cable pulling (power, signal, optical fibres…):

Special Optical fibres (polarisation maintaining fibre) to be pulled

DEC/DIC: DIF to be done

Racks (name and location):

BY11=UA43

Vacuum (bake outs, sectorisation…):

Bake-out

Special transport/ handling:

no

Temporary storage of conventional/radioactive components:

no

Alignment and positioning:

Pick-up to be aligned using classical survey target

Scaffolding: no

Controls: no

GSM/WIFI networks: no

Cryogenics: no

Contractor(s): no

Surface building(s): no

Others: no

5. IMPACT ON COST, SCHEDULE AND PERFORMANCE

5.1 IMPACT ON COST

Detailed breakdown of the change cost:

Fiber (40kCHF) Pick-up (10kCHF) Optic(20kCHF)

Budget code: 64065

5.2 IMPACT ON SCHEDULE

Proposed installation schedule:

LS2 (Q2/Q3 2020)

Proposed test schedule (if applicable):

no


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Estimated duration: 3 weeks

Urgency: no

Flexibility of scheduling: yes

5.3 IMPACT ON PERFORMANCE

Mechanical aperture: Same as today

Impedance: Should be better as we removed a long stripline replacing by a short button pick-up

Optics/MADX no

Electron cloud (NEG coating, solenoid…)

no

Insulation (enamelled flange, grounding…)

no

Vacuum performance: no

Others: no

6. IMPACT ON OPERATIONAL SAFETY

6.1 ÉLÉMENT(S) IMPORTANT(S) DE SECURITÉ

Requirement Yes No Comments

EIS-Access no

EIS-Beam no

EIS-Machine no

6.2 OTHER OPERATIONAL SAFETY ASPECTS

Have new hazards been created or changed?

Yes, using fibre laser – Safety file to be done when the system is fully designed

Could the change affect existing risk control measures?

Yes, using fibre laser – Safety file to be done when the system is fully designed

What risk controls have to be put in place?

Laser protection and signs to be put in place around the pick-up and in the rack in the gallery

Safety documentation to

update after the modification

yes


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Define the need for training or information after the change

no

7. WORKSITE SAFETY

7.1 ORGANISATION


IMPACT – VIC: x To be done

Operational radiation protection (surveys, DIMR…):

x

Radioactive storage of material:

x The BQKH.L4.B1 will be removed from the machine and stored

Radioactive waste: x

Non-radioactive waste: x

Fire risk/permit (IS41) (welding, grinding…):

x

Alarms

deactivation/activation (IS37):

x

Others: x

7.2 REGULATORY TESTS

Requirement Yes No Responsible Group

Comments

Pressure/leak tests: x TE-VSC

Electrical tests: x BE-BI

Others: x

7.3 PARTICULAR RISKS


Hazardous substances (chemicals, gas, asbestos…):

x

Work at height: x

Confined space working: x


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Noise: x

Cryogenic risks: x

Industrial X-ray (tirs radio):

x

Ionizing radiation risks (radioactive components):

x [Traceability by TREC.]

Others: x Fibre laser

8. FOLLOW-UP OF ACTIONS BY THE TECHNICAL COORDINATION

Action Done Date Comments

Carry out site activities:

Carry out tests:

Update layout drawings:

Update equipment drawings:

Update layout database:

Update naming database:

Update optics (MADX)

Update procedures for maintenance and operations

Update Safety File according to

EDMS document 1177755:

https://edms.cern.ch/document/1177755/1.0

replacement of bqks in ip4 by high bandwidth bpms in ip4 ...€¦ · in table 1, we also indicate...

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