photon beam and tagger working group status report richard jones catholic university glasgow...

Photon Beam and Tagger

working group status report

Richard Jones

Catholic UniversityCatholic University

Glasgow UniversityGlasgow University

University of ConnecticutUniversity of Connecticut

GlueX collaboration meeting, Newport News, Oct. 25-27, 2007

2


Outline Overview of progress in FY07 Diamond R&D Tagger engineering design Fixed counter array design SiPM studies and microscope prototyping Active collimator tests in Hall B Goals for FY08 Manpower and budgets

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Overview of progress in FY07 CLAS 20um thick diamond studied with using X-rays

at CHESS (Cornell synchrotron source) data analyzed by Y. Guangliang large-scale warping hypothesis confirmed

Tagger 35% design completed by Protvino Specification for 100% design under review CAD drawings of tagging counters produced for

Lehmann review, something like 35% design Detailed measurements of SiPM response as

function of Vbias and temperature at UConn

SiPM readout electronics design underway at UConn Successful test of active collimator during g8 run

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Diamond R&D 6-day exploratory run at

CHESS Nov. 1-6, 2006 Franz Klein Richard Jones Yang Guangliang Ken Finkelstein, CHESS staff

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Diamond R&D

CLAS target ladder

Xray beam

4-circle goniometer

beamshutter

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Diamond R&D

raw rocking curve image sequence

extracted shape of diamond,analysis by Y. Guangliang

X-ray images of 20m CLAS diamond taken at CHESS, November, 2006

peak/dip pair shallow depression

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Diamond R&D CLAS 20 micron diamond is badly warped

Is this a general problem at 20 microns, or just one bad one? Did it happen during thinning between 50 microns and 20 or

was this one warped earlier on? The curvature shows imprint of ink dots. Does the glue that

ties it to the mounting wires contribute to this strain? Further studies of thin diamonds are needed, but

The CLAS diamond was shattered during a remounting attempt GlueX needs its own collection of diamonds for study several new stones obtained by Ken Livingston from Element 6 assessment of new stones planned at CHESS next week

Development at UConn (undergrad thesis) underway to enable surface topology measurements with laser interferometry – mounting tests without X-rays!

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Tagger engineering design

35% design completed in May 2007 by IHEP

Some issues identified electron beam exit region alignment tolerances alignment plan and fixtures iron grade specification,

relation to field uniformity support of hodoscope array

on the “strongback” base stresses on vacuum chamber

from internal motion

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Fixed counter array design detailed mechanical design (F. Klein)

single support frame mounted on strongback remote controlled source moves on a rail

along full length of support structure

9.0 – 11.4 GeV photon energy

3.0 – 9.0 GeV photon energy

no gaps no overlaps capable of tagging

unpolarized beams at highest energy

gaps (samples spectrum) mainly for monitoring crystal

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SiPM studies and microscope prototyping

commercially available from Photonique (CPTA) and now Hamamatsu

intrinsic time resolution ~100 ps for 1 p.e. pulse

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SiPM studies, cont.Measurements at UConn on Photonique 4mm2 SiPM

Gain and PDE vary with Vbias

temperature

Vbias referenced with respect to break-down voltage Vbd

Vbd varies ±0.5V between devices individual control over Vbias required, similar to case of PMT (but no HV).

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SiPM studies, cont.

Measurements at UConn on Photonique 4mm2 SiPM

measured using a fast LED pulser at 570 nm (yellow)

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SiPM studies, cont.


measured using a fast LED pulser at 570 nm (yellow)

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SiPM studies, cont.


measured with threshold set at 0.5 photoelectrons

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Microscope readout

+

SiPMV

b[0]

E[0]SiPM

SiPMSiPM

SiPM

...

...

...V

b[4]

cfd

fadc[0]

f1tdc[0]

EnergyBins scint. clear

Fibers: Biasvoltages Detector DAQ Rack

+

SiPM

E[99]SiPM

SiPM

SiPM

SiPM

...

...

...V

b[499]

.

.

.

...

.

.

.

.

.

cfd

fadc[119]

f1tdc[119]

95 Echan @ 1 daqchan/Echan + 5 Echan @ 5 daqchan/Echan = 120 daqchan

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Microscope readout

dim box digital electronics external connections moderately light tight

dark box scintillating fibers PCB-mounted SiPMs signal preamps and

sum circuitry Vbias for each

channel received from digital board

interconnect plane PCB

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Microscope assembly, cont.

electrons

microscope assembly, exploded

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Active collimator tests in Hall B Installed in alcove 4/2007 TAC motion controls permit

sweep across the beam spot

outer horizontal sectors

inner horizontal sectors

2 sectors read out either inner or outer

sector pairs connected record I[0], I[1] vs. x

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Active collimator tests in Hall B signal strength excellent, ~3 x MC estimate – low E processes inner, outer peaks clearly seen, well matched asymmetric artifact peaks also seen: readout cables, connectors?

?

?

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Goals for FY08 Diamond R&D

assess crystals on loan from Element 6, Mainz at CHESS order several slices cut and thinned for GlueX learn from BNL source group about chemical etching

Tagger engineering design send out 100% design package monitor design process at key stages

Microscope prototype complete electronics design construct prototype 5x5 fiber array for testing

Active collimator tests repeat with 4 channels read out measure bandwidth vs noise for feedback stabilization circuit

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Manpower and budgets for FY08

University of Connecticut (student labor) one graduate student 2-3 undergraduates

Diamonds Glasgow University (postdoc salary)

Y. Guangliang possibility of technical help

IHEP Protvino (designers) engineering for tagger design

Yerphi Yerevan – (salary, travel) one physicist one tech for work on pair spectrometer

$50,000$50,000

$80,000$80,000

$60,000$60,000

$10,000$10,000

$20,000$20,000

$220,000$220,000

photon beam and tagger working group status report richard jones catholic university glasgow...

Documents

newport news

clas diamond

mechanical design

shape of diamond

micron diamond

budgets slide

fixed counter array

um thick diamond