Collimation Activities during EYETS A.Rossi on behalf of the Collimation teams

Summary IR7 Installation of a Low-Impedance Secondary Collimator (TCSPM) in slot TCSM.D4R7.B2 Installation of a primary collimator with orbit pickups (TCPP) replacing a TCP in slot TCP.C6L7.B1 Installation in IR7 of Primary Crystal Collimators (TCPC): on vertical in new slot TCPCV.A6R7.B2 and one horizontal TCPCH.A5R7.B2 replacing slot TCSM.A5R7.B2 IR5 Installation of two wire collimators in IP5 for Long Range Beam-Beam compensation replacing collimators in slots TCTPH.5R5.B2 and TCL.4L5.B2

Installation of a Low-Impedance Secondary Collimator (TCSPM) in IR7 LHC-TC-EC-0006 The LHC impedance budget is dominated by the contribution of the LHC collimators. Therefore, every secondary collimator slot in IR7 features a companion slot for the future installation of a low- impedance secondary collimator. This work is part of the collimation upgrades within HL-LHC. This ECR details the installation of one such prototype collimator, called TCSPM (Target Collimator Secondary with Pick-up Metallic – Molybdenum Graphite). It is a vertical collimator that will be installed in the slot TCSM.D4R7.B2. The cabling and the collimator support are already prepared so the intervention consists only of removing the replacement chamber and installing the new collimator.

Installation of a Low-Impedance Secondary Collimator (TCSPM) in IR7 IMPACT ON ITEMS/SYSTEMS Item/System : BE/BI BE/BI is responsible for the BPM acquisition. Cables were already pulled in IR7 for this purpose: they should be cut to the right length for connecting the slot. Controls units DOROS should be installed for the signal processing. The DOROS acquisition will be in RR77, in rack BY01. BE/BI support is required for the BLM acquisition associated to the collimator. A dedicated BLM is already available for each TCSM slot, so the impact should be minimal (re-configuration for interlock purposes). Item/System : BE/OP; BE/ABP Necessary change to the control system of the LHC must be performed to control the new collimator and read the new BPM signals.

Installation of a Low-Impedance Secondary Collimator (TCSPM) in IR7 IMPACT ON UTILITIES AND SERVICES Demineralized water: The circuit of cooling water of the TCSPM will have to be connected, in series to other collimators. Electricity, cable pulling (power, signal, optical fibres…): Cables have already been pulled (in LS1 + in first installation campaign before Run I) and need only to be connected to the new collimator Vacuum (bake outs, sectorisation…): The collimator will be validated by VCS before installation. Therefore, this installation will not cause any vacuum degradation. The TCSPM, once finished, will have to go through the standard vacuum qualification tests before installation in the tunnel. Survey: A fiducialisation has to be foreseen before it is descended into the tunnel. SURVEY needs to know the positions of the both targets by a metrology measurement few days/weeks before the alignment. The TCSPM component must be updated in the CERN layout database before any SU activities in the LHC tunnel. After installation in the tunnel, before the vacuum connection, standard alignment procedures apply.

Installation of a primary collimator with orbit pickups (TCPP) replacing a TCP in IR7 LHC-TC-EC-0005 A new design of the LHC primary collimator (TCP) that includes in- jaw orbit pickups (BPMs) was designed. This work is part of the consolidation of the collimation system A prototype of this collimator, which we call TCPP, has been produced and is ready for installation in the LHC. It is proposed to install it in the LHC during the EYETS2016, replacing the horizontal primary collimator of IR7 TCP.C6L7.B1. This will provide additional orbit measurements in IR7, also decreasing the alignment time for this collimator, and validate the TCPP design through operation at full intensity.

IMPACT ON ITEMS/SYSTEMS Item/System : BE/BI Installation of a primary collimator with orbit pickups (TCPP) replacing a TCP in IR7 IMPACT ON ITEMS/SYSTEMS Item/System : BE/BI BE/BI support is required for the mounting/dismounting of the BLM associated to the collimator. BE/BI is responsible for the BPM acquisition. Cables were already pulled in IR7 for this purpose: they should be cut to the right length for connecting the slot TCP.C6L7.B1. Controls units DOROS should be installed for the signal processing. The DOROS acquisition will be in UJ76, in rack BY01.

Installation of a primary collimator with orbit pickups (TCPP) replacing a TCP in IR7 IMPACT ON UTILITIES AND SERVICES Demineralized water: Same as the present TCP. Electricity, cable pulling (power, signal, optical fibres…): Same as the present TCP. Vacuum (bake outs, sectorisation…): Surface tests already performed. Survey: same comments as for TCSPM: fiducialization, database update, etc. Temporary storage of conventional/radioactive components: Storage of the present TCP.C6L7.B1 under the responsibility of EN/STI. It should be kept as an operational spare.

Installation in IR7 of Primary Crystal Collimators (TCPC) on Beam 2 LHC-TC-EC-0008 Within HL-WP5, crystal collimation is studied as a possible upgrade of the present multi-stage collimation system. Building on the good experience from the installation of crystals on Beam1 in the betatron cleaning insertion (IR7), it is proposed to install new crystals also on Beam 2 in the same insertion. Crystals are mounted on goniometers that allow adjusting crystal’s position and angle with respect to the circulating beam. We call this device TCPC (Target Collimator Primary Crystal). The new goniometers planned for Beam 2 improve the first prototype design already installed in 4L7 and 6L7 on B1, adding a better handling of functions for angular movements and fully bake-able components.

Installation in IR7 of Primary Crystal Collimators (TCPC) on Beam 2   DCUM centre [m] Affected beam Closest collimator slots Cables: Vertical goniometer TCPCV.A6R7.B2 + Collimator support + Dedicated BLMs 20145.2039 B2 TCSM.6R7.B1 (DCUM 19844) 2 m from the device New slot and if possible, new controls cables. Otherwise, can temporarily use the one of the nearest TCSM slot. Horizontal goniometer: TCPCH.A5R7.B2 + Dedicated BLMs 20090.4180 Replace existing slot TCSM.A5R7.B2   Existing phase II slot. Collimator support already available.

Installation in IR7 of Primary Crystal Collimators (TCPC) on Beam 2 IMPACT ON ITEMS/SYSTEMS Item/System: LHC collimation system: The proposed installation relies on collimation installations (cabling, slots, …) that are required for the future upgrades of the system. As it was done for the B1 installation, a quick-installation concept is required for the installation of the crystal setup and for a possible removal in case of needs for other collimation purposes. HL-LHC-WP5 will fund new control cables for the new installation. Item/System: BE/BI One additional beam loss monitor (BLM) is required downstream of each goniometer for beam-based alignment purposed, with data acquisition and updating of database. The possibility to install additional diamond BLMs for fast loss measurements is also under evaluation (optional). This would provide bunch-by-bunch measurements at crystal locations.

Installation in IR7 of Primary Crystal Collimators (TCPC) on Beam 2 IMPACT ON ITEMS/SYSTEMS Item/System: Machine protection The new goniometers must also be connected to the machine interlock. It is proposed to setup a dedicated input in the CIBU for the B2 (as it was done for B1). Item/System: BE/OP New devices will have to be properly configured in the top level control layer of LSA. Item/System: TE/VSC Integration of both horizontal and vertical TCPC crystal collimators will be done in the slots with corresponding length therefore no additional changes in the vacuum sectors layout is needed. Removal of existing chambers. Installation of new drift chambers and pumping assemblies.

Installation in IR7 of Primary Crystal Collimators (TCPC) on Beam 2 IMPACT ON UTILITIES AND SERVICES Electricity, cable pulling (power, signal, optical fibres…): The horizontal goniometer would not require new cables because it is installed in a “phase II” slot (TCSM.A5R7.B2). For future low- impedance collimators for HL-LHC it is proposed to pull new cabling for this slots. The vertical goniometer can in principle re-use cables of the nearest empty TCSM slot, i.e. TCSM.6R7.B1 (note that this is a B1 slot). On the other hand, also in this case our preferred choice is to pull new cables, for the same reason. Special transport/handling: The 2 new goniometers are extremely delicate, and shall be transported and installed and aligned similarly to the recommendations of document LHC- TEC-EC-0001 written for the goniometers previously installed on B1.

Installation in IR7 of Primary Crystal Collimators (TCPC) on Beam 2 IMPACT ON UTILITIES AND SERVICES Vacuum (bake outs, sectorisation…): The new goniometers are fully bake-able. Their installation will be subject to the approval from the VSC team. Survey: The 2 new goniometers are extremely delicate, and shall be transported, installed and aligned similarly to the recommendations of document LHC-TEC-EC-0001. After installation, goniometers should be properly fiducialized by the Survey team. It is also noted that a new low support installation (EN-STI) is needed for the vertical TCPC, and as so, survey team will need to mark the floor with its position in advance. In order to do that, the component must be created / updated in the CERN layout database before any SU activities in the LHC tunnel. Controls: The controls of these devices are under the responsibility of EN/STI.

Installation of two wire collimators in IP5 for Long Range Beam-Beam compensation LHC-TC-EC-0007 Long-range beam-beam (LRBB) interaction is presently considered as one the limitation of LHC and HL-LHC performance. Scope of this installation is to demonstrate LRBB compensation using a local wire on both sides of the IP on a “weak” beam, where the BB effects from the “strong” beam are enhanced. The wires are embedded into tungsten (Intermet-TM180) collimators that will replace two existing collimators: TCTPH.4R5.B2 and TCL.4L5.B2, where the phase advance and beam size ratio is favorable for the compensation.

Installation of two wire collimators in IP5 for Long Range Beam-Beam compensation IMPACT ON ITEMS/SYSTEMS Item/System: LHC collimation system The TCT and TCL will work as normal collimators. Reading of the wire tension and temperature will be done using spare wires in collimation cables. Item/System: BE/BI New BPMs acquisition and database updating is necessary. Wire connection, control and testing is responsibility of BE/BI. Default connection to internal wires: BBCWI.4L5.B2 and BBCWE.4L5.B2 for the “internal” and “external” wires (internal = between the beams, external = on the opposite side), for those in the TCL.4L5.B2 BBCWI.4R5.B2 and BBCWE.4R5.B2 for the “internal” and “external” wires in the TCTPH.4R5.B2

Installation of two wire collimators in IP5 for Long Range Beam-Beam compensation IMPACT ON ITEMS/SYSTEMS Item/System: Machine protection Still under discussion. Power converters will be stopped via the WIC. Cables have been requested. Item/System: BE/OP Wires will have to be properly configured. Still under discussion. Note: wire shall be lock-out during interventions Rack reference Converter Type Location Collimator RYME01 LHC600A-40V UL557 TCTH.4R5.B2 USC55 TCL.4L5.B2

Installation of two wire collimators in IP5 for Long Range Beam-Beam compensation IMPACT ON UTILITIES AND SERVICES Electricity, cable pulling (power, signal, optical fibres…): Cabling for the in-jaw BPMs of the slots TCL.4L5.B2 are needed because the present TCL does not have pickups. Requested. Cables to connect wires power converters to WIC requested. Cables to connect wire tension and temperature read-out between collimation/BI racks to WIC requested (racks are in the same hall) Survey: The sectors require special attention to vacuum chamber alignment. Collimators will be aligned prior vacuum connection. Alignment will be checked after connection with measurement of the 63Ø chambers on the external beam lines on both sides of the IP.

Installation of two wire collimators in IP5 for Long Range Beam-Beam compensation IMPACT ON UTILITIES AND SERVICES Vacuum (bake outs, sectorisation…): like any other collimator. Cryogenics: Protections for the QRL may have to be envisaged during installation of the TCL.4L5.B2 Temporary storage of conventional/radioactive components: Storage of the present TCTPH.4R5.B2 and TCL.4L5.B2 under the responsibility of EN/STI. It should be kept as an operational spare.