Silicon strip detectors for two-dimensional soft x-ray imaging at normal incidence Pedro Rato Mendes LIP Lisbon and University of Algarve, Portugal Amsterdam,

Silicon strip detectors for two-Silicon strip detectors for two-

dimensional dimensional

soft x-ray imaging at normal soft x-ray imaging at normal

incidenceincidence

Pedro Rato MendesPedro Rato MendesLIP Lisbon and University of Algarve, PortugalLIP Lisbon and University of Algarve, Portugal

Amsterdam, 09-12 September 2002

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Outline

• Collaboration members

• Objectives

• Experimental setup

• Energy calibration

• Imaging results

• Conclusions and future work

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Collaboration members

M. C. Abreu a, G. Baldazzi b, D. Bollini b, E. Cabal Rodriguez c, W. Dabrowski d, A. Diaz Garcia c, M. Gambaccini e, P. Giubellino f,

M. Gombia b, P. Grybos d, M. Idzik d,f, A. Marzari-Chiesa g, L. M. Montano h, F. Prino i, L. Ramello i, P. Rato Mendes a, S. Rodrigues a, M. Sitta i, P. Sousa a,

K. Swientek d, A. Taibi e, A. Tuffanelli e, R. Wheadon f, P. Wiacek d

a LIP and University of Algarve, Faro, Portugal

b Dipartimento di Fisica dell’Università di Bologna and INFN, Bologna, Italy

c CEADEN, Havana, Cuba

d Faculty of Physics and Nuclear Techniques, Academy of Mining and Metallurgy, Cracow, Poland

e Dipartimento di Fisica dell’Università di Ferrara and INFN, Ferrara, Italy

f INFN , Torino, Italy

g Dipartimento di Fisica Sperimentale dell’Università di Torino and INFN, Torino, Italy h CINVESTAV, Mexico City, Mexico

i Dipartimento di Scienze e Tecnologie Avanzate dell’Università del Piemonte Orientale and INFN , Alessandria, Italy

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Objectives

Develop a simple prototype system for 2-D

soft x-ray imaging using silicon strip detectors

• Motivations for this prototype– spin-off from high-energy physics– RX64 chip designed for this application– simple laboratory setup and data-acquisition– advanced education for young physicists

RX64 and its main applications: talk by L. Ramello, this conference

W. Dabrowski et al., RX64 – A Fully Integrated 64-channel IC for Readout of Silicon Detectors Used for X-Ray Position Sensitive Measurements, IEEE NSS/MIC 2001, San Diego

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Experimental setup

• Equipment– board with 1-sided microstrip detectors and RX64 chips

• 300 m thick Si, 132 strips at 100 m pitch (ITC-IRST, Trento, Italy)

• RX64 chip by W. Dabrowski and collaborators (Cracow, Poland)

• one or two chips per board (64 or 128 channels)

– PC with NI PCI-DIO-96 interface + LabVIEW 6i software– scanning system controlled by stepper motor– radiation sources (57Co, 109Cd, 241Am for fluorescence)– power supplies, cables

• Two-dimensional image acquisition– acquire 1-D profiles for each collimator position– form 2-D image by juxtaposition of 1-D profiles

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Experimental setup

64

silicon microstrip detector

RX64

RX64

- 64 channels (preamp, shaper, discriminator)

- 64 pseudo-random counters (20-bit)

- internal calibration circuit (1 mV to 30 mV)

- I/O on chip (interface with external bus)

PC

NationalInstruments

PCI-DIO-96LabVIEW 6i

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

First test board (one RX64 chip)

0.6 1.0 cm2

detector

RX64

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Energy calibration

• Method– perform discriminator threshold scan– differentiate integral spectrum– fit energy peaks on differential spectrum

integral spectrum differential spectrum

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Energy calibration

Calibration using Co57 and Cd109 sources (board with one RX64 chip, average on all channels)

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Energy calibration

Calibration using Am241 x-ray fluorescence source (board with two RX64 chips, average on all channels)

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Scanning system

scanning

detector board

stepper motor

radioactive source

Pb collimator

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Imaging results – one RX64 chip

Pb0.5 mm

thick

300 kBq 109Cd source – 22 keV Ag K x-rays15 mm thick Pb collimator, 300 µm wide slit

microstripdetector

scanningsystem

1.0 1.0 mm2

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Imaging results – two RX64 chips

300 kBq 109Cd source – 22 keV Ag K x-rays15 mm thick Pb collimator, 300 µm wide slit

LOW CONTRASTsnail shell

HIGH CONTRAST8-pin integrated circuit

1.0 1.0 mm2

Pedro Rato Mendes et al. IWoRID’2002 - Amsterdam

Conclusions

• Prototype main features– one-sided silicon microstrip detectors– simple readout electronics based on RX64 chip– simple 2-D scanning system

• Future developments– larger area sensors / more readout chips– new chip version with two thresholds– x-ray tube as radiation source

We have built and tested a simple prototype for 2-D soft x-ray imaging