ICRM RMT Working Group Review

John Keightley

john.keightley@cec.eu.int

ICRM : RMT Working Group

RMT Working Group (RMT – WG) re-instated following ICRM 2001

Loss of Many “experts” in the field over the last years VERMI Workshops

RMT Sessions have continued at ICRM Broad Range of Topics

Coincidence Counting Monte Carlo Modelling New Detector Systems/Techniques

Bolometry (LNHB) Digital Data Acquisition for Coincidence Counting Comparisons Large Area Source measurements …

RMT Working Group

In my opinion, this range of topics is too large for RMT Working Group Coordinators to keep control or make valuable input …

3 major tasks assigned to Working Group Digital Coincidence Counting (DCC) Data Conversions and

comparisons (John Keightley) DCC data set Simulations (John Keightley) Tritium Comparisons (Mike Unterweger)

Does not reflect full range of topics covered Volunteers for other areas ? (Please !) Discuss in Working Group Meeting

Digital Coincidence Counting (DCC) Data Conversions and comparisons

Coincidence Counting for radionuclide standardisations

Conventional Coincidence Counting

ADC

SCA

Dead Time

Delays

Coinc. Mixer

Scalers

MCA

Etc…

Digital Coincidence Counting (DCC)

NPL/ANSTO

KRISS

CMI

VNIIFTRI

DCC Data

List Mode with Time Stamps for each event

Digital Coincidence Counting Data Format Conversions

Conversion routines written as 32 bit DLLs in Visual C++

Only recently finished DCC – CMI conversion (last week)

Binary Data Format : Viewed in “Hexadecimal” formLarge data sets.

DCC Comparisons

Each system uses different data format and independent analysis software

HOWEVER : WE SHOULD ALL GET SAME RESULTS FOR MEASURED ACTIVITY Same input data sets

Initial Tests with data from 56Mn source NOT to be published … First attempt at data conversions looks

promising

NPL/ANSTO

Digitisation does not impose extra dead time

12 bit ADCs : 20 MSPS

VNIIFTRI

Pulse Time and Height

(no shape data)

10 s non extending dead time inherent in digitisation process

10 bit ADCs

KRISS

Pulse Time and Height (12 bit)

(no shape data)

8 s non extending dead time inherent in digitisation process

28 bit clock at 100 MSPS

CMI

Pulse Time and Height (8 bit)

No shape data

“Common” variable dead time

Preliminary Results : 56MnKRISS and DCC (Computer Discrimination) Gamma Gate : Channels 861 – 1004 (12 bit scale) Coincidence Resolving Time : 1.5 s per channel CMI (Computer Discrimination) Gamma Gate : Channels 53 – 63 (on 8 bit scale) Coincidence Resolving Time : 1.68 s per channel VNIIFTRI I need more info !! Beta Efficiency Range

High% Low %

Extrapolated Activity (kBq)

KRISS DCC CMI VNIIFTRI 95.6 86.8 3.24 3.36 3.36 ? 95.6 82.4 3.33 3.36 ? 95.6 77.0 3.40 3.36 3.36 ?

DCC Simulation (DCC_SIM)

Introduce in Working Group Meeting

Test software routines at higher count rates than currently achievable in hardware i.e: REALLY test corrections for dead times,

resolving times etc …

Mimic output of Digitiser cards

KNOWN activity, extrapolation fit parameters