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