| Internal Note | |
| Report number | CERN-ACC-NOTE-2021-0021 |
| Title | MD2193 – Impedance Measurements of the TCSPM Prototype Collimator |
| Author(s) | Amorim, David (Universite Grenoble-Alpes (FR)) ; Antipov, Sergey ; Arsenyev, Sergey ; Azzopardi, Gabriella (CERN) ; Biancacci, Nicolo (CERN) ; Bruce, Roderik (CERN) ; Carver, Lee Robert (University of Liverpool (GB)) ; Fitterer, Miriam ; Giordano, Francesco (Universita e sezione INFN di Napoli (IT)) ; Lamas Garcia, Inigo ; Mazzacano, Giacomo (Universite Grenoble-Alpes (FR)) ; Mereghetti, Alessio ; Metral, Elias (CERN) ; Pesah, Arthur Chalom ; Redaelli, Stefano (CERN) ; Salvant, Benoit (CERN) ; Shiltsev, Vladimir ; Valuch, Daniel (CERN) |
| Corporate author(s) | CERN. Geneva. ATS Department |
| Publication | 2021 |
| Imprint | 20 Jun 2021 |
| Number of pages | 17 |
| Subject category | Accelerators and Storage Rings |
| Accelerator/Facility, Experiment | CERN LHC |
| Keywords | LHC ; collimator settings ; cleaning inefficiency ; impedance |
| Abstract | In view of the HL–LHC project, it is planned to exchange 9 out 11 of the LHC secondary collimators in IR7, made of graphite, with low–impedance ones. In order to optimise the new design, a prototype of collimator with a selection of low–impedance materials coated on the surface of the jaw was installed in the LHC during the 2016 Extended Year End Technical Stop, to be able to verify with beam the beneficial effects on impedance. This report summarises the measurements taken with the prototype collimator during MD2193, carried out in MD block 1 of 2017, on the night between 30th June and 1st July. An additional set of measurements was collected in parallel to MD2191, during MD block 3 of 2017, on the night between 17th and 18th September; in that occasion, an HL–LHC type of nominal bunch was used. As done in past activities of the same type, the impedance was estimated by measuring the tune shift induced on the beam by varying the collimator gap; the tune was reconstructed from the damped oscillations of the beam when coherently kicked with the ADT in AC–dipole mode, in order to have a strong tune signal. Measurements fit very well with expectations; however, Molybdenum remains the most promising material among the coated ones, even if a resistivity larger than the expected one was measured during the MD. |
| Other source | Inspire |
| Submitted by | [email protected] |
ჩანაწერი შექმნილია 2021-07-30, ბოლოს შესწორებულია 2021-08-06
