Minutes of the 63rd MTE meeting held on Thursday September 27th 2012

Present :

S. Damjanovic, P. Demarest, M. Giovannozzi, C. Hernalsteens, M. Hourican , C. Pasquino.

Excused :

S. Gilardoni, J. Borburgh, R. Brown

 

1. Concerning the protection of the dummy septum (Action: TE-ABT):

   • A temperature sensor should be installed to measure the blade temperature. It will be interlocked with beam injection to protect the dummy septum in case of potential accident.

   • A BLM will be installed and it will be interlocked as it is done for all BLMs. This will also provide protection of the dummy septum.

   • The consequence of full beam loss on the dummy septum blade should be considered (Action: TE-ABT and DGS-RP).

2. The catalogue of the intervention for estimating the dose delivered to personnel is being prepared (Action: TE-ABT).

3. Concerning the shielding (Action: TE-ABT):

   • It is proposed to have two connection flanges on the upstream and downstream side of the dummy septum. On the downstream side the vacuum pipe will be connected rigidly to the dummy septum tank.

   • The downstream wall of the concrete shielding will be built with very few (possibly only one) blocks: this would allow a quick dismounting of the wall.

   • To remove the dummy septum one should:

     • Remove the top of the shielding

     • Remove the downstream part of the shielding

     • Disconnect cooling, disconnect stepping motor cables and position feedback cables, disconnect temperature sensor, disconnect grounding cable (R. Brown recommends not to use quick release Walther water connections, but use flat joint connections which can be disconnected before the concrete blocks are removed. A few seconds longer but much more reliable. Walther connections have been removed from all PS aux magnets as they all proved to be leaky with age).

     • Remove RF bypasses upstream and downstream on vacuum flanges

     • Remove the colliers of the two flanges

     • Lift up the dummy septum

   • The order of these operations should be optimised to reduce the dose delivered to people.

   • The shielding should be finalised also based on the outcome of the analysis of the vacuum situation (see later).

4. The situation of the impedance computation will be presented at the meeting on 11 October (Action: ABP).

5. Concerning the vacuum in sector 20, additional studies are presented:

   • It seems difficult to install additional pumping capacity in the region of MMU14 as already now the pumping capacity is limited by the conductance.

   • An alternative would be to check whether additional pumps could be installed in the side of the pick-up. It is reminded that MMU14 will be removed during LS1 and this could allow changing the vacuum chamber (Action: TE-VSC and J. Belleman).

   • Another solution could be to install the additional pump directly on the dummy septum. However, this should not impact on the removal possibilities of the device, i.e., the presence of the vacuum pump should not require dismantling more shielding. Two options are at hand (Action: TE-ABT, TE-VSC):

     • To install a vacuum pump beneath the dummy septum tank.

     • To install a vacuum pump upstream of the dummy septum to avoid any interference with the shielding. This would have the drawback of limiting the conductance of the system.

   • The case of increased desorption due to the presence of ferrites will be presented at next meeting, where the various options will be reviewed.

   • It is also reminded that the absence of beam screen would alleviate the situation, thus excluding the need for additional pumping.

6. A meeting to discuss the possibility to install beam monitoring device has been organised. A possibility consists of installing the screen in front of the dummy septum blade. The blade will be slightly displace downstream without any impact of the external dimensions of the vacuum tank. The details should be provided by the BI specialists (Action: BI).