Proton Calorimetry/Experimental Runs/2017/September7

Beam tests of the Nuvia 10 mm, 4 mm and 3 mm scintillator sheets with PRaVDA CMOS pixel sensors (PRIAPUS) at the Birmingham Cyclotron with a 28 MeV beam.

Pre-data Taking Information and Notes

• The tests were carried out with an energy of 28 MeV (32 MeV was unavailable as the cyclotron had recently been through repairs). No Bragg Peak measurement was carried out to confirm the exact beam energy due to time restrictions.
• The beam was run without a scattering foil. A 1 cm diameter uniform beam was achieved by placing a 1 cm collimator in the beam, with a beam scan onto film confirming the size. An ionisation chamber was placed upstream of the collimator to accurately monitor the current.
• The dynamic range of the CMOS sensors is 14 bits. The electron conversion value from ADC is 50 electrons per ADC value. The measurements to establish this were carried out at the beginning of experimentation with the sensors and this value may have changed due to radiation damage etc.
• From previous measurements, the average background value per pixel is ~ 700.
• The data was recorded at 45 frames/second.
• The scintillator stack was set up perpendicular to the proton beam, with the exposed sides of the scintillator facing the sensors:

• The scintillator stack was quite well aligned with the horizontal centre of the beam. We did our best to align the vertical centre of the scintillator stack with the beam as well, however as can be seen from the image below, where the black "line" shows the divide between and hence the centre of the sensors, the beam hit just below centre:

• The working directory on the PRIAPUS computer where the data is stored is:

idMateData\Bham070917\

• The directory the data is stored at UCL in is:

/unix/pbt/data/birmingham/sept_2017

Data Taking

Type of run	Current	Scintillator sheets used	Scintillator arrangement	Notes	File name
Background	N/A	3 x 3 mm	ABC	Background ADC count slightly higher than usual Tiles are grouped together in a tight formation (until mentioned otherwise)	Background_1
Beam	1 nA	3 x 3 mm	ABC	Saturation of sensor, ADC values at 14,000	28MeV_3mmscint_ABC_1nA_1cmC
Beam	0.1 nA	3 x 3 mm	ABC	Current reduced by a factor of 10 Beam dropped during run	28MeV_3mmscint_ABC_100pA_1cmC_1
Beam	0.1 nA	3 x 3 mm	ABC	Saturation of sensor	28MeV_3mmscint_ABC_100pA_1cmC_2
Beam	10 pA	3 x 3 mm	ABC	Sensor no longer saturated, but no separation due to formation of tiles	28MeV_3mmscint_ABC_10pA_1cmC
Beam	10 pA	3 x 3 mm	ABC	Due to gap between the sensor and the scintillators there is an overlap in the light collected by the sensor and no separation of the scintillators can be seen In order to see some separation, place the scintillators with a gap of ~ 1-2 cm between each sheet This setup remains in place until mentioned otherwise Lights were left on for the first run. Data not useable!	28MeV_3mmscint_ABC_spread_10pA_1cmC
Beam	10 pA	3 x 3 mm	ABC	Lights off this time!	28MeV_3mmscint_ABC_spread_10pA_1cmC_2
Beam	10 pA	3 x 3 mm	ABC	Repeat measurement for reproducibility	28MeV_3mmscint_ABC_spread_10pA_1cmC_3
Beam direction	N/A	N/A	N/A	Measure the direction of the beam relative to the screen by shining a laser on the sensor Saturation of the sensor	Laser_beam_direction
Beam direction	N/A	N/A	N/A	Cover some of the sensor not to saturate it Beam direction determined to be (for the top panel display): SCREEN <--- BEAM (where the arrow represents the direction of the beam)	Laser_beam_direction_cover
Beam	10 pA	4 mm and 3 mm	3A 4A	Alignment: 4A [gap] 3A <--- BEAM Lights were left on for this run. Data not useable!	28MeV_3mmA_4mmA_spread_10pA_1cmC
Beam	10 pA	4 mm and 3 mm	3A 4A	Lights off this time!	28MeV_3mmA_4mmA_spread_10pA_1cmC_2
Beam	10 pA	4 mm and 3 mm	3A 4A	Repeat measurement for reproducibility	28MeV_3mmA_4mmA_spread_10pA_1cmC_3
Beam	10 pA	3 mm and 4 mm	4A 3A	Scintillator plates switched around Alignment" 3A [gap] 4A <--- BEAM	28MeV_4mmA_3mmA_spread_10pA_1cmC
Beam	20 pA	3 mm and 4 mm	4A 3A	Continue with this configuration and increase current until we get to the maximum current that won't saturate the sensors First, double the current	28MeV_4mmA_3mmA_spread_20pA_1cmC
Beam	25 pA	3 mm and 4 mm	4A 3A	Increase current to 25 pA Possible saturation of sensors	28MeV_4mmA_3mmA_spread_25pA_1cmC
Beam	20 pA	3 x 3 mm	ABC	The maximum current before saturation is ~ 20 pA Repeat tests with 3 scintillator plates at this current Alignment: 3C [gap] 3B [gap] 3A [gap] <--- BEAM	28MeV_3mmscint_ABC_spread_20pA_1cmC