F.Murtas1IMAGEM DDG GEM technology for X-ray and Gamma imaging IMAGEM l Detector setup l First results on X-ray imaging l First results on Gamma ray imaging l Requests

F.Murtas2IMAGEM DDG A triple GEM Chamber GEM foil 70 µm140 µm A Gas Electron Multiplier (F.Sauli, NIM A ) is made by 50  m thick kapton foil, copper clad on each side and perforated by an high surface-density of bi-conical channels; Several triple GEM chambers have been built in Frascati in the LHCb Muon Chamber framework* * M.Alfonsi et al., The Triple-GEM detector for the M1R1 muon station at LHCb, N14-182, 2005 IEEE NSS Conference, Puerto Rico

F.Murtas3IMAGEM DDG Cartesian Small angle Pads  Gain and readout functions on separate electrodes  Fast electron charge collected on patterned anode  Energy signal detected on lower GEM electrode GEM Readout 40% of electron signal 60% of electron signal Particle conversion Gain Readout

F.Murtas4IMAGEM DDG Radiography with GEM Radiography with Xray at 8 KeV of a small mammal (1200 x 640 Pixels) 32 mm Pixel size of 50x50  2 … Despite the good imaging properties of this readout structure, at higher rates (exceeding a few hundred kHz over the detector area) the reconstruction efficiency is limited by ambiguities due to multiple hits within one readout cycle, resulting from the intrinsic time resolution of the readout electronics (around hundred ns). With conventional two-dimensional projective read-out structure, no information is obtained which would allow the resolution of those multiple hits.

F.Murtas5IMAGEM DDG Fast X-ray plasma diagnostics (ENEA Frascati, Italy) Readout: 32 2 mm 2 pixels TIME-RESOLVED PLASMA ACTIVITY: D. Pacella et al, Rev. Scient. Instrum. 72 (2001) 1372 R. Bellazzini et al, Nucl. Instr. and Meth. A478(2002)13 Time (ms) Counts/50 µs

F.Murtas6IMAGEM DDG Gamma converter LEM triple GEM double GEM triple GEM Different gamma converters have been studied trying to convert gamma rays up to hundreds KeV in electrons; the electrons produced are therefore drifted through the triple GEM structure to produce a detectable signals. A Large Electron Multipliers (LEM) made with 0.5 mm thick G10 layer drilled with 0.5 mm holes have been also tested.

F.Murtas7IMAGEM DDG Pads and readout An array of 64 pad (8 cm long) has been realized on a 10x10 cm 2 PCB. The pads are readout on the PCB back plane. The 64 pads are readout with LHCb ASDQ FEE. A VME DAQ, with scalers, reads the rates produced by gamma irradiation, in a defined time gate. ( 1 x 1 mm 2 )

F.Murtas8IMAGEM DDG Scan setup : Gamma ray 3 mm lead screen LEM BOX Several source has been used Cesio (660 KeV) Sodium (511 KeV) Tecnezio (140 KeV) Settings : Triple 980 V 500 V gamma

F.Murtas9IMAGEM DDG Scan setup : X ray XRay Labview program developed by Chen for scan control, lem hv setting and DAQ Camac readout with a 12 channel scaler LEM BOX 3 mm lead screen Electric plug image Smooth movement for 20 sec total time For each “column” 100 ms acquisition time 6 KeV Xray 20  A filament current

F.Murtas10IMAGEM DDG Xray 6KeV

F.Murtas11IMAGEM DDG Xray movie An X ray movie has been realized with this triple GEM gamma camera ; A rotating pencil box (with 2 pens inside) illuminated by a 6 KeV X-Ray can be easily inspected Each frame has been kept in a time gate of 100 ms Each pixel of 1x1 mm 2 is measuring 700 Hz The Xray gun behind the pencil box is running with a filament current of only 30  A Hz cm

F.Murtas12IMAGEM DDG Gamma 140 KeV

F.Murtas13IMAGEM DDG A SPECT image This image has been obtained with the same gamma camera set on a time gate of 4 sec; The maximum rate measured on a single pad is 15 Hz with a background less than 2 Hz. Four 99 Tc (140 KeV) sources 10x2 mm 2 wide have been put in front of the scanner system at a distance of 3 cm from the camera : First two sources : 4 mm apart Second two : 6 mm apart 4 mm6 mm 10 mm

F.Murtas14IMAGEM DDG Next studies

F.Murtas15IMAGEM DDG Sci-fi gamma converter lead collimator scintillating fibers Trying to increase the chamber efficiency, some tests are in progress using the Kloe calorimeter structure as collimator and gamma converter photocathode 2 cm 3 cm mrad relative efficiency 0 cm 1 cm 2 cm angle resolution of 50 mrad

F.Murtas16IMAGEM DDG High density electronics The scanner system can be removed only if a high density electronics readout can be plugged on the pad backplane. ASIC We are studying and looking for “commercial” ASICs like : ALTRO (Alice), MEDIPIXII, BEETLE (LHCb), APV25 (Compass) to design and realize PCB able to accept a bonding of this chips. The main problem is the maximum detector capacitance acceptable. Are foreseen designs on fast readout through USB connection.

F.Murtas17IMAGEM DDG Medipix

F.Murtas18IMAGEM PIXIE (Bellazzini)

F.Murtas19IMAGEM DDG Requests for IMAGEM Studies on converter: New gamma converter using Kloe calorimeter structure Photocathodes and GEMs Studies on electronics : Designs and realization of PCB Bonding of chips on PCB Designs and realization of fast readout through USB conn. Persone : F.Murtas 0.2, P.Ciambrone X, C.Morone (TOV) 0.2, O.Schillaci (TOV) 0.5 Servizio Elettronica : 0.3 G.Corradi Consumo : 10 Keuro Missioni interno : 2 Keuro