The LHCb Muon System Upgrade

Q&A on TDR:discussion

Alessandro Cardini INFN Cagliari Pr

esen

ted

to LH

CC o

n Dec

embe

r 3rd

Timeline• Received LHCC report on Jan 24th – very positive feedback!

• Meeting Friday 7th @9:00 with Upgrade Steering Group

• Then sent answers to reviewers to have TDR approved at the next LHCC session in March

3 January 2014 A. Cardini / INFN Cagliari 2

LHCC Report Introduction

3 January 2014 A. Cardini / INFN Cagliari 3

General Comments

Nothing specific on the muon system, any changes on the muon part will be discussed together with CALO and RICH

3 January 2014 A. Cardini / INFN Cagliari 4

Q&A 1

Answer 1

Reviewers did not understand the table, apparently they confused stations and regions - we should just explain that the target is the sum of available + to_be_built

3 January 2014 A. Cardini / INFN Cagliari 5

Q&A 2

Answer 2:

The needs of every subsystem are somehow specific and also depend on the detector technology

In the muon system we readout the digital information of the muon chamber hits (position and time) because we need a fast detector and we require it to be perfectly timed within the bunch-crossing to guarantee a high system efficiency

With all these considerations in mind we are designing a highly-integrated, radiation-hard fully digital chip that needs to be easily integrated in the already existing system and that allows to perform muon specific operation (specific voltage level adapting, time adjust, time histogramming, specific data compression/reduction, event formatting). We will heavily profit of the experience in the design of the currently installed SYNC chip

In general LHCb uses common solutions as much as possible (TELL40, for example). However, subsystem back-end solutions depends heavily on the detector used and also on decisions taken more than ten years ago. As a consequence a generic chip for the back-end is not always possible - but other general common projects like GBT, Versatile Links and DC-DC converters will be heavily used by all LHCb sub-detectors3 January 2014 A. Cardini / INFN Cagliari 6

Q&A 3

Answer 3

Original references of our manuscript were

I believe that Guy’s intention was to remove all references to proceedings and this was a leftover

3 January 2014 A. Cardini / INFN Cagliari 7

Q&A 4

Answer 4

The plot shows the average number of hits per event per channel in a given region, normalized to 1 at 7 TeV

We can provide a new plot with the label “m(E)/m(7 TeV)” to better clarify this

3 January 2014 A. Cardini / INFN Cagliari 8

Q&A 5

Answer 5

M2Ri: rate effect, which causes a high dead time

M5R1: an effect of this level (smaller than 0.5%) is an artificial effect of the method used to determine efficiencies in the last station. The muons are tracked down to M5, but some of them do not reach M5, and they are however counted as inefficiencies. It has been checked (see muon performance paper) that this effect is of the order of 0.2-0.4% but the plot shown does not include this correction

3 January 2014 A. Cardini / INFN Cagliari 9

Q&A 6 (1)

Answer 6-1

The message is that, thanks to the direct comparison with what we get from data taken in two different data taking conditions, the prediction mechanism (which disentangles the part of inefficiency that depends on the intensity) works, so we can rely on it to estimate inefficiencies at larger ν3 January 2014 A. Cardini / INFN Cagliari 10

Q&A 6 (2)

Answer 6-2

These plots are a preliminary estimate on the muon system performances in the upgrade conditions and are based on the current muonID algorithms.

In general, a looser track definition will improve the muon identification efficiency, however at the expenses of the muon misidentification

This is for example clearly visible for low momentum tracks, where muon identification efficiency is higher but there is also a corresponding increase of the misidentification probability

A careful evaluation of the muon identification performance in the upgrade - also including RICH and CALO subsystem – is currently under study, and is based on the full LHCb upgrade MC`s3 January 2014 A. Cardini / INFN Cagliari 11