SPS wire scanner prototype Benoit Salvant and Carlo
SPS wire scanner prototype Benoit Salvant and Carlo Zannini for the impedance team With the help of Elena Chapochnikova, Jose Ferreira Somoza, Jose Varela and BI colleagues SPSU meeting - 27/02/2013
Question • Bernd informed us that the wire scanner tank is likely to be installed without the wire scanner. • Is that acceptable from longitudinal point of view?
Eigenmode simulation results Mode frequency (GHz) Q 1 0. 568 2 0. 665 3 0. 666 4 0. 832 5 0. 864 6 0. 871 7 0. 875 8 0. 884 9 0. 998 10 1. 025 11 1. 026 12 1. 061 13 1. 127 14 1. 135 15 1. 143 16 1. 149 17 1. 153 18 1. 160 19 1. 224 20 1. 256 Rs k. Ohm 6712 2 7681 3 7818 48 5706 36 7903 9 7737 12 8009 9 7883 23 11670 19 6541 10 6527 4 8561 123 8022 1 8017 0 6982 1 8939 0 8838 11 7764 4 9911 60 7481 0 Above TE 11 cutoff of attached pipe (~1. 09 GHz ) Is this acceptable from longitudinal point of view? Q should be lower in real life ECR coming. We will anyway request bench measurements (probes in particular to assess the Q)
“Ugly” devices in the SPS? (from impedance point of view)
One example: near QF 41801 CDD database ~2007 From SPS OP site December 2013 Some drawings missing and some not up to date
Shunt impedance in Ohm Impedance of “bare” bellow transition Frequency Qs are of the order of 4000 to 8000
Shunt impedance in Ohm Impedance of transition with bellows Frequency Qs are of the order of 500 to 3500 Shunt impedance could reach of the order of 100 k. Ohm (depends on actual length).
How to proceed? • The safest is to survey the machine in the tunnel half cell by half cell (drawings are not up to date…). Can probably be done in two days. • Survey points: – Potential issues for impedance – Where are the shielding of pumping ports missing (needs VAC colleagues as not obvious from outside) – Where are damping resistors installed? – Other ideas? • When? – Now is good as a lot of time and no radiation – But some parts of the machine are still not reinstalled • Who? – Carlo, Jose, Fritz, Benoit ? needs
Shunt impedance in Ohm QF 32210 100 k. Ohm Frequency (GHz) Also of the order of 100 k. Ohm (if Q is correct)
- Slides: 10