TECHNICAL SPECIFICATION NO:
Multianode Photomultiplier Tube/Voltage
Divider Assemblies for the
Hall B CLAS12 RICH
Version 1, August 8, 2013
By: Valery Kubarovsky
APP: __________________
Valery Kubarovsky
Hall B Staff Scientist
SOTR
___________
Date
APP: __________________ ___________
Rolf Ent
Date
Associate Director
Review Team Member
APP: __________________ ___________
Volker Burkert
Date
Hall B Leader
Review Team Member
APP: __________________ ___________
Patrizia Rossi
Date
Deputy Associate Director
Review Team Member
1. Introduction
Detectors that can image Cherenkov rings, called Ring Imaging Cherenkov (RICH), represent a
powerful tool in identifying charged particles produced in nuclear and sub-nuclear interactions in
a wide range of energies. Their performance allows to measure with extremely high precision the
speed of particles, through the detection of the Cherenkov light that accompanies their passage in
a dense medium with a velocity larger than the velocity of light in the same medium.
The CLAS12 RICH detector uses aerogel as a radiator of the Cherenkov light and multianode
photomultipliers (MA-PMTs) as a photo-detector.
MA-PMTs matches the aerogel Cherenkov light yield as detect light in the visible and nearultraviolet region with high efficiency, minimize the dead area and simplify the detector layout
geometry thanks to the high packing fraction, allow to efficiently discriminate the background
being fast and with a high time resolution, and provide the required spatial resolution.
In order to complete the first sector of the RICH detector in time for the beginning of the
CLAS12 data-taking, foreseen in the first quarter of 2016, the CLAS12 RICH Collaboration has
planned a procurement of a total of 430 multianode photomultipliers in the next 2 and half years,
with a possible extension of one additional year.
The procurement will proceed in few separate orders. The MA-PMT cost has to be intended as
commensurate to the amount of the total furniture and not to the one of the single orders. The
initial price may be reduced in case of new convenient market quotations of the multianode
PMTs. It is accepted that the price may vary following the exchange rates between yen and
dollars at the time of the single orders. The delivery schedule is intended to follow the sequence
of the orders.
In case the total number of purchased MA-PMTs will be lower than 430, a compensation is
foreseen. This corresponds to the difference in the single MA-PMT price commensurate to the
planned and the purchased amount, multiplied by the purchased MA-PMTs number.
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2. Statement of Work
The selected vendor shall provide all tools, materials, labor, equipment, and facilities to
fabricate, test, and deliver all of the 430 multianode photomultiplier tube/voltage divider
assemblies for the RICH detector with the dimensions and other specifications as given in this
document. In addition, the vendor shall deliver all documentation and test results for the
individual assemblies.
3. MA-PMT/Divider Performance Specifications
The following are the required performance specifications for the RICH MA-PMT/voltage
divider assemblies:

The spectral response must be in the range of 300 to 650 nm, with the peak response
around 400 nm.

The PMT window must be planar and made from borosilicate glass or a material with
similar transparency.

The photocathode must be bialkali.

Typical quantum efficiency in the peak wavelength interval must be better then 20%.

The weight of the assembly has to be less then 200 g.

The MA-PMT has to have matrix structure with 8x8=64 pixels.

The dimensional outline must be inside the 10% of 50x50x30 mm2.

The packing fraction must be better then 85%.

The pixel size must be in the range (5.5x5.5) up to (6.5x6.5) mm2.

The typical gain must be at least 1.5x106 at nominal HV.

Typical variation of gain has to be 1:2.

The anode dark current of entire tube at nominal HV must be less then 1 nA at 25oC.

Typical cross talk has to be less then 5%.

The assembly components include MA-PMT and divider.
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4. Optional requirements (keep on separate quotation)





Total dark current from all pixels at nominal HV must be less then 3 nA.
Maximum gain variation 1:4
MA-PMT only without divider
Positive high voltage
HV pin input type
5. Testing by Manufacturer
The manufacturer must test and document the individual MA-PMT/divider assemblies before
delivery. These tests must include at least measurements of the average gain of the entire tube,
the dark current and relative gain map at nominal HV to be sure that each unit meets our
minimum requirements. Each assembly must be marked with a unique identifier that can be
matched with its corresponding test data.
6. Delivery Schedule
The PMT/divider assembly delivery schedule will be based on the JLab funding profile as noted
in the Bid Schedule. The delivery has to be completed on December 15, 2015.
The units should be shipped to the following address:
Dr. Valery Kubarovsky
12000 Jefferson Avenue
Suite 5
Newport News, VA 23606
USA
7. Shipping
The PMT/divider assemblies should be packaged in individual boxes with appropriate packaging
to prevent damage during shipment. The individual boxes should then be packaged in larger
boxes with sufficient packaging to minimize the possibility of damage during transport/handling.
The test documentation for the units should be included in the box.
8. Acceptance
Acceptance testing of the PMT/divider assemblies shall be completed by authorized personnel
within the standard 1 year manufacturer’s warranty after receipt of the assemblies. The
acceptance tests will consist of procedures to confirm that the assemblies meet the performance
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specifications. They are not intended to substitute for the tests performed by the manufacturer.
Shipments of PMT/divider assemblies passing the following checks will be accepted:

Each PMT/divider assembly will be inspected visually for physical damage. If the unit
inspection is satisfactory, the units will be tested further to determine where they meet the
performance specifications as outlined above. Tests will include checks of signal
integrity, signal-to-noise ratio, gain and high voltage requirements. The manufacturer
will be notified by JLab personnel and must replace any units that fail inspection within a
period of 60 days.
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