TEST BEAM PERIOD: two weeks at the T9 from May 27 to June 10.

TEST BEAM AREA
The composition of the beam for the secondary line, it's not very different from T10. It comes from the same beam on target. It has a different production angle, but it's a 5 milliradians difference. So in terms of the composition of the beam, it's quite similar for the mixed beam.
The area in general is a bit bigger. So we have around 11 meters while in T10 we have around 7 to 8 meters. Then from the beam point of view, they have two profile monitors also. The beam height in T9 is 1351 mm. In T10 was more or less the same, maybe a little bit more, 1355 or 1360 mm. Perhaps a few of us will come to CERN to visit the area in March,just to understand. Wednesdays are normally when they have changes and the area is open. So Wednesdays are normally a good time to visit. Abu Bak is in charge for the East Area, but the easiest always is to add comments in the system and then everyone gets it. If Abu, for example, is not available, someone else can also reply.


PIONS
Since we don't care about the charge, they suggest to use negative pions, since for negative pions we have basically 90% pions until about 1 GeV. Below 1 GeV, the electron percent goes up.
Positive pion are highly contaminated by protons, essentially.
Plots show that for 15 GeV 10 GeV, 6 GeV or 5 GeV it's almost 99% pions for the negative polarity.
The contamination from Muons is very low, and also from electrons.
For the electrons, they even have an absorber. So normally, if we're only interested in the pions, they will insert this absorber which will kill even the small percent of electrons that can exist in these momenta. For example, at 3 GeV, we have 35% electrons, but this can be killed with the absorber, to have almost pure pions.
We could definitely stick with this configuration of negative pions at different momentum. Uh, so please take note of, I mean, of this configuration. 


KAONS
Kaons go from 1% to 3%, depending on the momenta, but it's quite flat in principle for the different momentum for the kaons. The only way to check the kaons would be to tag it with the Cherenkov and for this they have to see with threshold pressure on the momenta up to what it would work. If we go to very low momenta, the threshold pressure rises, and we just don't have the capability to then set the pressure accordingly.
The kaons are not properly detected and we get mostly pions for the kaons.
The rate is already quite low, for negative pions, and it is around 10^4, 10^5, with 0.4 seconds spill. So 2*10^4, 2*10^5 per second. Kaons are 1 to 3% of the beam. It's very difficult to positively tag the Kaons.
There will be something like 10 to the 200 kaons per spill. In the positive beam, we have close to a factor 10 more always because we start with the proton on target. So the positive beam has more rate. So they can also try to go to the positive polarity, to have the rate per spill higher for the kaons.
Even 100 kaons/s are not bad, because we are limited from acquisition. 100 kaons/s on which area?
This depends on the momenta as well. At higher momentum, they are able to focus better the beam because less multiple scattering. So we can have up to 8 mm sigma at the highest moment, as we go to lower momenta, we have more scattering. So then it can become one cm, 1.5 cm. For the muons, they don't have control, because there's a lot of multiple scattering, but for the Hadron beams at high momentum they can focus quite well and at lower momentum, to about 4 or 5 GeV, it's still reasonable full width will be within 3 cm.

Then: if we want pions, it's better to have a negative polarity if we want kaons it's better to have positive polarity.

PI/K DISCRIMINATION
Beams are pion and kaons with very little contamination from leptons, but pions and kaons will be mixed. 
For the kaons, for example, with CO2, which is normally what they advise to have at these momenta for the threshold Cherenkov, at 5 GeV, the threshold pressure is around 11.5 bars and for the pions is 0.9. So, for example, if they set one threshold Cherenkov to around 2 bars, we should tag everything up to the pions, and then if the another one is set around 13 bars, then we tag everything up to the kaons, and then with the anti-coincidence, we should be able to tag only the kaons.
However if we go to 4 GeV, then the threshold pressure for the Kaons is 17 bar, and this we don't have the capacity to do.
So: from 15 to 5 GV, we are able to separate pion from kaons with the anti-coincidence signal. At higher momenta they should check the efficiency, but in general, 5 to 15 GeV should work. The efficiency may differ depending on the momentum.
Below 5 GeV, we could not.

ANTI-COINCIDENCE SIGNAL
They can provide us the analog anti-coincidence signal directly from the detector, and then we do the discrimination and the integration with our DAQ. So we get that raw analog signal directly from the PMT of Cherenkov. We get the signal directly from the detector in the zone.

CHERENKOV SETTING
We will have to change the pressure by ourselves. We can already see the threshold pressures at the different momentum for the different particle, and then normally one should try to set it around one and a half bars over the threshold pressure to get the best efficiency for the photons.
They will advise when we will start our beam time, we'll check the threshold signals, the size of the signals as well, and if we think that it needs to be adjusted, or the high voltage needs to be adjusted, we can directly contact the BI experts and they can help with this adjustment.


MOMENTUM RESOLUTION
They don't have an absolute measure of the momenta, but the magnets themselves are quite precise.
A 4 GeV can be 3.9 GeV, or a 4.1 GeV.
The magnets are quite precise, but when they do the calibration of the angle to the magnetic field, this calibration can have some uncertainties, and this is of the order of a few percent normally.


MUONS
The configuration is very similar to T10, but the muons, as in T10, as well as we go to higher momenta, we get more contamination with the hadrons in the mixed beam configuration.
Better to have nobody in the area during the data acquisition.
Actually for muons there are two ways. If we want really pure muon beam, we can do so by putting in the collimator plus the beam stopper, and this then really stops all hadrons almost to over 99%. And in this case, the rate will be much lower, but we will have very pure muon beam. The other option is to only use the beam stopper or only use the collimator. With the collimator in T9, we get a bit more decay of the hadrons, because the collimators are more downstream, so the rate is a bit better, and also the collimator has longer radiation interaction length than the beam stopper.
So with the collimator, the muon purity is also better, but we will not be able to access the zone in this configuration. On the other hand, if we would like to access the zone, then we can do it only with the beam stopper.
This is the configuration that we used in the past. Normally the rate they can reach is few 10^3. If they really push it can be 10^4. 
For muons it's a much larger beam. The whole width is ~8 centimeters.

PLAN
We could probably have one week devoted to muons and one week devoted to pions and kaons.


GAS SYSTEM 
In the East area, they have only one gas barrack, which is used in common between T9 and T10, so it should be the same as in 2024. If we want to use a premixed bottle, or we want to do a mixture usually the procedure is the same. 
We will let them to know what gas we want to use, and then they will make it available in the zone.
We could consider if we can use premixed bottle. It depends on the fact that if we want to change the gas mixture or not. This we have to decide between us before.


EQUIPMENTS
We will need one Daisy Table that was included in the request, and also a rack where to mount our high voltage system. We will have also rotating tables, two of them, so we can lift our detector and rotate it. 

TRIGGER
We don't need the signal from their scintillators, but they asked to provide them our signal, because that helps to scan the beam and really change the focus according to our setup. They have scintillators (10*10 cm2) from which we could get the trigger, but they will not be close to our detectors: one is 2 m upstream our setup, and the other one is 10 meters upstream.
They are too far. They cannot be moved to other positions, since these scintillators also works as the trigger for the threshold Cherenkov.
We have 5*5 cm2 and we can have up to 15*15 cm2. Perhaps we'll use the 5*5 cm2 ones. But it's an option that we can discuss.
We can use their scintillator signals, but if we can provide our 5*5 cm2 signal, this could be very useful for them.
Indeed our scintillators are 20 cm away one from the other. So it will be a very precise setup.
If we provide them the coincidence, they can scan the beam on our coincidence and optimize the beam rate on our coincidence. So we'll check the focus.
We need to understand how to provide the signal.
It's not a showstopper, but it's easier if they can have it to check the beam on our trigger.
The logic is NIM standard, with signals at least 20 ns wide.