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The first part of the program took place at CERN using a variety of different particle beams (e, e+, p, pions, photons) and ranging in energies from tens of MeV up to hundreds of GeV.
The second part of the program exploits the high energy heavy ion beams available at GSI to measure the response of the CU to such radiation. Heavy ions are an important component of primary cosmic rays, and the LAT plans to use them to calibrate the CAL and ACD subsystems during flight operations. Therefore the GSI test is primarily meant to verify the on-orbit calibration procedure for the CAL, which uses also the ACD and TKR subsystems for triggering and tracking.
The CU beam test at GSI is also a first test with heavy ions for the TKR subsystem.
List of
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measurements
Below is a partial list of specific topics of intereset for the interest, grouped per subsystems
TKR: saturation effects from heavy ions on ToT signal, tracking performance, instrument deadtime
CAL: verification of quenching factors (measured at GSI 2003), test on-orbit calibration procedure and code
ACD: verification of CNO trigger, verify ACD dynamic range
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The run at GSI is scheduled between november 15 and november 20, with beam avaialble between november 18 8AM and november 20 8AM19 8PM.
Installation and debug will take place on november 15, 16, 17.
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Run period | Operation mode | Ions | Energy | Rate |
|---|---|---|---|---|
18/11-8AM 19/11-8PM | daytime, parasitic mode to therapy for daytime (approx 20 min irradiation with 20 min break), timesharing with other experiment overnight | C, Xe (few hours overnight, TBCprobably on 19 anytime) | 1.5GeV/n | O(100)Hz/cm^2 |
The beam focus can be moved from a few meters upstream the detector down to the CU location, in order to enlarge or squeeze the beam spot. This feature can also be used to decrease/increase particle density.
Trigger considerations
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Since the allocated beam time is not very much, we should exploit the capability of operating the CU with multiple trigger engines. This was demonstrated to work at CERN, we need to define more engines and test them.
Moreover, effects like pedestal drift and different investigations to be performed, suggest that we run in such mode to cover more topics in a short data-taking time.
SUch operation must be verified prior to start with beam, and immediately when the beam is on, to make sure that we can proceed with the test in such mode.
List of runs
Below is a list of specific run requests. Plese update the table and notify Luca Latronicoso that a proper run schedule can be developed and agreed with GSI
Purpose | preferred schedule | Ion | Energy | Rate on CU | Beam focus | CU configuration | Trigger | notes | contact reference |
|---|---|---|---|---|---|---|---|---|---|
Test multiple trigger engines prior to beam | nov 16-17 | NA | NA | NA | NA | enable multiple trigger engines | CNO, periodic, internal trigger | take runs at different CNO thresholds, periodic trigger frequency | luca |
Test multiple trigger engines w beam | nov 18 | C | 1.5Gev/n | 100Hz | any | enable multiple trigger engines | CNO, periodic, internal trigger | take runs at different CNO thresholds, periodic trigger frequency | luca |
Monitor beam rate and conditions | nov 18 | C | 1.5Gev/n | 10-1000Hz | play with focus to change beam intensityon CU | 4 range readout, non zero suppression | external | to be repeated shortly per configuration change | luca |
Rate scan | after multiple engine work | C | 1.5Gev/n | 10-1000Hz | play with focus to change beam intensityon CU | multiple trigger engines | CNO, periodic, internal trigger | vary periodic trigger frequency to induce pedestal drift | luca, eric g |
Tracking performance | any time | C,Xe | 1.5Gev/n | 10-1000Hz | far and near focus | multiple trigger engines, flight settings, 4range-readout NZS | CNO, internal trigger | investigate tracking at different rates | leon, INFN |
Tracking saturation | any time | C,Xe | 1.5Gev/n | 10-1000Hz | far focus | multiple trigger engines, flight settings | CNO, TKR trigger, 4range-readout NZS |
| leon, INFN |
CAL calibration | nov 18 | C,Xe | 500MeV/n, 1GeV/n, 1.5GeV/n | 100Hz | far and near focus | multiple trigger engines | CNO, periodic, internal trigger | verify quenching factors, CAL calibrations, ACD partial calibration | CAL team |
Energy scan | nov 19 | C,Xe | 100MeV/n - 1.5GeV/n in steps | 10-1000Hz | far and near focus | multiple trigger engines | CNO, periodic, internal trigger | attempt to simulate different ions by varying ionization energy | nicola |
Secondary ions with target | nov 19 | Xe | 1.5GeV/n | 10-1000Hz | far and near focus | multiple trigger engines | CNO, periodic, internal trigger | attempt to get different ions by shooting beam through a target | benoit |