Experimental activity on the TOP-IMPLART linear accelerator Fabrizio Ambrosini Sapienza University of Rome - DIET, Rome Attività sperimentali relative all’acceleratore lineare Titolo presentato sull’abstact M. Vadrucci, A. Ampollini, G. Bazzano, F. Bonfigli, F. Marracino, R. M. Montereali, P. Nenzi, L. Picardi, M. Piccinini, C. Ronsivalle, V. Surrenti, M. A. Vincenti (ENEA Frascati, Roma) M. Balduzzi, C. Marino, C. Snels (ENEA Casaccia, Roma) P. Anello, C. De Angelis, G. Esposito, M. A. Tabocchini (ISS, Roma) M. Balucani, R. Cicchetti, A. Klyshko (Sapienza University of Roma - DIET, Roma)

TOP - IMPLART Project VARIABLE CURRENT 30keV SOURCE 3 – 7 MeV RFQDTL VERTICAL LINE TERMINAL HORIZONTAL LINE EXTRACTIONS 3cm 7mm SCDTL-1PMQ

Outline Experimental results on the first SCDTL module ( MeV): Simple characterization method of small high gradient permanent magnet quadrupoles (PMQs) Experimental results with low energy (3-7 MeV) proton beams: - Radiobiological experiments - LiF detectors development - Porous Silicon for micromachining - RF cold tests - Proton beam transport: propagation in a short DOFO channel (4PMQs) - Proton beam transport: propagation in the complete DOFO-like channel (9PMQs) mounted on the SCDTL (RF off) - RF hot tests

Experimental results with low energy (3-7 MeV) proton beams Low proton fluences (10 6 protons/cm 2 ): VERTICAL BEAM LINE High fluences (> protons/cm 2 ): HORIZONTAL BEAM LINE for the study of in vitro models of cellular mechanisms involved in the carcinogenesis process development to develop a LiF particle detector and to realize porous silicon for Micro-Electro- Mechanical-Systems (MEMS) Q 1 Q 2 Q 3 Q 4 High fluences

A campaign of radiobiology experiments has started on Chinese Hamster V79 cells for cell killing induction studies within a dose range of Gy at different: - beam energies - dose rates (i.e. varing the charge for pulse) - dose (varying the irradiation time) Cells with their culture liquid (6μm thickness), in a cylindrical sample holder with a diameter of 13 mm Mylar sheet (50μm thickness) Dosimetric control: GafChromic films EBT3 suitably calibrated at LNL Laboratories. The irradiated area has a uniformity of 90% After irradiation the cells were: - detached from the Petri dish - diluted - plated at the appropriate concentrations for survival evaluation. An initial shoulder followed by a straight portion, that can be well fitted by a linear- quadratic function of the dose S= exp(-αD-βD 2 ) The dose response curve obtained was in agreement with literature data Radiobiological experiments Kapton window 50  m thick Au scattere 2  m thick Al collimator 2mm diameter

LiF detectors development The irradiation of LiF induces the formation of primary and aggregate CCs, which are stable at RT. By a fluorescence optical microscope equipped with a cooled s-CMOS camera, it was possible to record the transversal proton beam intensity profile by acquiring the PL image of irradiated LiF. Linear behaviour with fluence covering several orders of magnitude of fluence range, irradiating LiF films grown on a glass substrate. F 2 ed F 3 + luminescono nel rosso (670nm) e nel verde (530 nm)

Porous Silicon for Micro-Electro-Mechanical- Systems Silicon Bulk Micromachining Cross section of exposed silicon after porous silicon formation. The area in the image corresponds to the edge of one masked area. Porous silicon appears lighter in the image and has a rough texture. The thickness of the non-porous area is 31µm (corrisponding to the stopping range of 1.8 MeV) because of the imaging angle (67°). Experimental setup used to irradiate silicon sample Transferred pattern after porous silicon removal

RF cold test: the structure has been tuned and completely characterized on RF bench Smith chart showing the coupling of the π/2 mode Q reflection measurement Resonant modes measured in reflection from the central tank The measured modes dispersion curve Experimental results on the first SCDTL module ( MeV) Bead pull measurement: squared electric field along the axis on the SCDTL structure Tuners for tuning acceleranting tanks Tuners for tuning coupling cavity and flattening the field Holes for pickups

Proton beam transport: propagation in a short DOFO channel (4PMQs) Beam spot after 1 PMQ (#1) in position 4 Beam spot after 1 PMQ (#2) in position 4 Beam spot after 4 PMQ (#1,2,3,4) Fluorescent target

The final beam spot on a fluorescent target (included within a diameter of 4mm) Proton beam transport: propagation in the complete DOFO-like channel (9PMQs) mounted on the SCDTL (RF off)

The reduction of the transmission (60% of 200μA in input) respect to the computed value (84% for a 7MeV beam with a nominal energy spread included in ±100 keV) is due: mainly to the presence of a low energy satellite in the input beam. to residual misalignements Arc current DTL field RFQ field Input beam current Output beam current Al thickness (µm) Transmission Energy (MeV) a. u. - beam transmission in increasing thickness Al absorbers. - curve fit by smoothing spline - first derivative for range distribution. - energy spectrum from relation energy- range Al thickness (µm) Proton beam transport: propagation in the complete DOFO-like channel (9PMQs) mounted on the SCDTL (RF off)

After 10h of conditioning it has been possible to feed the structure with a forward power of 0.9 MW. Signal acquired from power meter with EPM-P probe controlled via GPIB: (left) reflected power, (right) forward power. - The SCDTL-1 structure has been coupled to the high power RF line coming from a TH2090 Klystron (P max =15MW); - the pulse lenght (flat top) is 3.5 μs; - the repetition rate available is only 6.25 Hz; - the total attenuation was 97.7 dB: 57.7 from a WR284 Thomson directional coupler and further 40 dB with cable attenuators. RF hot tests

FFT Simple characterization method of small high gradient permanent magnet quadrupoles R rif = 0 mm R rif = 1 mm

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