8/13/2008Detector Council Meeting1 HBD Status TK Hemmick for the HBD Crew.

8/13/2008 Detector Council Meeting 1

HBD StatusHBD Status

TK Hemmick for the HBD TK Hemmick for the HBD CrewCrew


Brief OverviewBrief Overview• HBD WestHBD West

– ~1 Month of stability tests completed (looks good)~1 Month of stability tests completed (looks good)– 100% functional100% functional

• Cosmic Rays and Scintillation seen in all GEMstacks.Cosmic Rays and Scintillation seen in all GEMstacks.– Presently under Nitrogen Flow.Presently under Nitrogen Flow.– Required for delivery:Required for delivery:

• Re-install air-cooling system (plumbing presently off)Re-install air-cooling system (plumbing presently off)• Final noise chasing (Cu tape & mylar shields)Final noise chasing (Cu tape & mylar shields)• New Survey (Really Necessary???)New Survey (Really Necessary???)• PHENIX Gas System Ready.PHENIX Gas System Ready.

• HBD EastHBD East– 4/10 GEMstacks installed (fast method)4/10 GEMstacks installed (fast method)– Need more GEMs (10 more on the way from WIS)Need more GEMs (10 more on the way from WIS)– Just waiting around (tent is pretty boring right now).Just waiting around (tent is pretty boring right now).

• Initial Tests on new OFFLINE algorithm begun.Initial Tests on new OFFLINE algorithm begun.– Affects choices for items stored in new Compact CNTs.Affects choices for items stored in new Compact CNTs.

• Trigger on HBDTrigger on HBD– Possible but needs dedicated team & serious workPossible but needs dedicated team & serious work


Cosmic Measurement Cosmic Measurement SystemSystem

Setup

Coincidence

Scintillator

CAMAC


Result from the 1Result from the 1stst Test Test

• Cosmic Ray Trigger paddles cover 14 pads.Cosmic Ray Trigger paddles cover 14 pads.• In “Forward Bias” one expects both ionization and In “Forward Bias” one expects both ionization and

scintillation signals from cosmic rays.scintillation signals from cosmic rays.• Source of exponential as scintillation confirmed in Source of exponential as scintillation confirmed in

two ways:two ways:1.1. When recording a nearby pad that it not under the paddles, When recording a nearby pad that it not under the paddles,

the MIP disappears, but the pedestal and scintillation remain.the MIP disappears, but the pedestal and scintillation remain.

2.2. When recording data in reverse bias, MIP disappears, When recording data in reverse bias, MIP disappears, scintillation & pedestal remain.scintillation & pedestal remain.

MIP ResponsePedestal

Scintillation Mean Scint = 20 chLandau MPV = 300 chLandau MPV ~15


WN4 SpectraWN4 Spectra


Some GEM Reminder Some GEM Reminder NumbersNumbers

• GEMstack = 3 GEMs.GEMstack = 3 GEMs.• GEM has 28 strips.GEM has 28 strips.• Strip has 20 MStrip has 20 M• Each stack runs from Each stack runs from

a triple chain.a triple chain.• If one strip is shorted, If one strip is shorted,

the GEM is 20 Mthe GEM is 20 M instead of infinity. instead of infinity.• Current Draw in the chain increases by Current Draw in the chain increases by

1.5%.1.5%.– Old Model: Trip @ standing current + 1.5%Old Model: Trip @ standing current + 1.5%– New Model: Trips are more complicated.New Model: Trips are more complicated.


Cascading trips.Cascading trips.

• When operating under Gain Conditions, a discharge will propagate and When operating under Gain Conditions, a discharge will propagate and avalanche.avalanche.

• Avalanche will produce large current surge & may trip subsequent GEM Avalanche will produce large current surge & may trip subsequent GEM strips.strips.

• Tripping the strip in a neighbor GEM produces a MUCH larger current surge.Tripping the strip in a neighbor GEM produces a MUCH larger current surge.• 1.5% trip settings have been too low.1.5% trip settings have been too low.


Who’s Afraid of the Big Bad Who’s Afraid of the Big Bad Trip?Trip?• Run 7:Run 7:

– Trip settings were 1.5%.Trip settings were 1.5%.– Mesh-GEM spark phenomenon & LeCroy 1471 Mesh-GEM spark phenomenon & LeCroy 1471

FPGA bug combined to deliver MASSIVE FPGA bug combined to deliver MASSIVE discharge from the mesh if the GEMstack was discharge from the mesh if the GEMstack was disconnected.disconnected.

– Tripping the LeCroy to “save the GEMs” saved Tripping the LeCroy to “save the GEMs” saved nothing and initiated a damage-inducing trip.nothing and initiated a damage-inducing trip.

• COMPASS:COMPASS:– NO TRIP CIRCUITS!!NO TRIP CIRCUITS!!– Occasional discharges do not damage GEMS.Occasional discharges do not damage GEMS.

• PHENIX Future:PHENIX Future:– Compromise…Compromise…– Run trip settings low in software and high in Run trip settings low in software and high in

hardware.hardware.


Trip Rate reasonable Trip Rate reasonable

• Hardware trip = one strip in 2 Gems.Hardware trip = one strip in 2 Gems.• Software trip = 1.5%Software trip = 1.5%• Above result is what happens with all stacks in the HBD on at the Above result is what happens with all stacks in the HBD on at the

same time.same time.• Additional benefits of new scheme:Additional benefits of new scheme:

– Trips are no longer “massive” (every stack).Trips are no longer “massive” (every stack).– Trip rate is smooth function of threshold (how low rate do you want?)Trip rate is smooth function of threshold (how low rate do you want?)

• BIG NEWS:BIG NEWS:– Lots of trips early in the testing…NO DAMAGE!Lots of trips early in the testing…NO DAMAGE!


Our trouble maker for big trips was stack South 4. With new resistor chain change voltage to dV=460V (all other were at 480 V):

Works stable at this dV, with large signal !!!


Update on the HBD gas Update on the HBD gas systemsystem• The main goal is to increase The main goal is to increase

flow to the two detector as flow to the two detector as much as possible without much as possible without compromising gas quality.compromising gas quality.Three places changes can be made

1. The Monitoring Hut2. The rack in the mixing house3. The small bypass panel in the IR

(this probably will not do much)The HutThe Hut• Modify Flow path to gas analyzers. Modify Flow path to gas analyzers.

((DONEDONE))• Reduce restrictions by replacing Reduce restrictions by replacing

flowmeters and valves (flowmeters and valves (DONEDONE))• Install gauge and new valve to make Install gauge and new valve to make

switching from vacuum in the monitor switching from vacuum in the monitor to gas a little easier. to gas a little easier. ((DONEDONE))

• Replace H20 sensors with ones that work.


HBD Gas Rack: In HBD Gas Rack: In ProgressProgress

Solenoid valve to the vent had to be changed to accommodate much higher flow rate than designed (10x higher). Custom valve ordered and in hand

Old flowmeter with built-in valves needs to be replaced with low impedance flow indicator and separate valve. This valve controls how much gas passes through the purifiers. Right now all gas pass though it. This flowmeter was already replaced once mid-Run6 to increase flow to the HBD

Old flowmeter without built-in valves needs to be replaced with low impedance flow indicator. This indicates how much total gas is going to the system. This flowmeter was already replaced once mid-Run6 to increase flow to the HBD. It need to be replace again for the higher flowrate.

Pressure transmitter may need to be replaced. This was at upper reading limit in Run6. With the new flowmeters, the higher pressures in the rack may not be needed

Replace Purifier to handle the higher gas flow--DONE


Algorithm IdeasAlgorithm Ideas• Old: Old: ClusteringClustering- Clusters could grow Clusters could grow

to any size or shapeto any size or shape- Fails with Fails with

scintillationscintillation

• New: Hub and Spoke (HnS)- Reconstructed electron location is used as center for search region

-Hub: multiple-pad sum at center

-Spoke: multiple-pad sum at some R and phi away from center


Two Possible Pad Sizes: 3 Two Possible Pad Sizes: 3 vs 7vs 7

- Two options that are presently coded

8/13/2008 Detector Council Meeting 15Singles Doubles


HBD Trigger (aka WTF??)HBD Trigger (aka WTF??)• Physics:Physics:

– Charged pion signal spin asymmetry is MORE sensitive Charged pion signal spin asymmetry is MORE sensitive than neutral pion spin asymmetry.than neutral pion spin asymmetry.

– We don’t record this since we don’t have a high We don’t record this since we don’t have a high momentum pion trigger in pp collisions.momentum pion trigger in pp collisions.

– When operated in ++ field, the HBD only sees blobs for When operated in ++ field, the HBD only sees blobs for high momentum pions (req’s RICH coincidence)high momentum pions (req’s RICH coincidence)

• HardwareHardware– The new RPC trigger module is 100% HBD-compatable.The new RPC trigger module is 100% HBD-compatable.– Adding these to the HBD crate will allow HBD signals Adding these to the HBD crate will allow HBD signals

to reach the trigger system.to reach the trigger system.– What it takes:What it takes:

1.1. Extra RPC trigger boards…Extra RPC trigger boards…$$$$$$..2.2. Extra code to have HBD data flow on backplane… Extra code to have HBD data flow on backplane… Chi? Chi?

Chuck?Chuck?3.3. Extra code (modules?) in the trigger system to use HBD Extra code (modules?) in the trigger system to use HBD

data. data. LajoieLajoie4.4. NEW CIRCUIT BOARD to put an optical copy of RICH NEW CIRCUIT BOARD to put an optical copy of RICH

signals onto new Fiber media signals onto new Fiber media ChuckChuck..5.5. Additional dedicated people putting in significant effort.Additional dedicated people putting in significant effort.

(Stony Brook cannot provide item #5).(Stony Brook cannot provide item #5).


ExtrasExtras


HBD System TriggerHBD System Trigger• The ADC boards has 2 pairs of cables output per The ADC boards has 2 pairs of cables output per

board, 4 LVDS signals.board, 4 LVDS signals.– It cover 48 channelsIt cover 48 channels

• If you output 48 bits per beam clock, one bits per If you output 48 bits per beam clock, one bits per channel. We only need one pair cable.channel. We only need one pair cable.

• The RPC trigger module could handle 10 ADC The RPC trigger module could handle 10 ADC boardsboards

• The maximum data output is 384 bits.The maximum data output is 384 bits.– This is less than 480 bits for 10 ADC boards.This is less than 480 bits for 10 ADC boards.

• The optics we used are the chip sets 8b/10b The optics we used are the chip sets 8b/10b encoding. Except for the upgrades detector encoding. Except for the upgrades detector system, all other system use GLINK chip setsystem, all other system use GLINK chip set– If HBD trigger need to merge with the existing If HBD trigger need to merge with the existing

detectors to form a trigger. We have issues with L1 detectors to form a trigger. We have issues with L1 system.system.


RPC trigger moduleRPC trigger module• RPC TDC board has 64 channel per boardRPC TDC board has 64 channel per board

– For every beam clock, we output 64 Y/N bits by 2 For every beam clock, we output 64 Y/N bits by 2 differential LVDS cable in the backplane.differential LVDS cable in the backplane.

• 320 bits per cable.320 bits per cable.

• We need to move 3 TDC’s data by 1 optical cableWe need to move 3 TDC’s data by 1 optical cable– 64*3 bits per beam clock.64*3 bits per beam clock.

• The optics will run 2.8 gbits/sec.The optics will run 2.8 gbits/sec.

• One trigger module will handle 6 TDC modules. One trigger module will handle 6 TDC modules. – 2 optical cables2 optical cables

• The input cable can handle maximum 10 pairs The input cable can handle maximum 10 pairs cable for the L1 trigger primitives.cable for the L1 trigger primitives.– We could just connect all the traces to the FPGA.We could just connect all the traces to the FPGA.


HBD West Trip statistics

Nominal Resistor chain current = 146uA

Trip size distribution

0

2

4

6

8

10

12

0 2 4 6 8 10 12

Trip size, stack

#

Distribution of the Tripped modules

0

5

10

15

20

25

30

0 1 2 3 4 5 6 7 10 11

module number

#

HV output number

Mean and Peak Trip limit = 170 uA


Mean and Peak Trip limit = 175 uA

Trip size distribution

0

1

2

3

4

5

0 1 2 3 4 5 6 7 8

Tirp size, stack

#

Distribution of the Tripped Modules

0

2

4

6

8

10

12

14

0 1 2 3 4 5 6 7 10 11

Module number

#

3 South 4 South

0, North, South


More statistics:

•At 170uA there were 37 trips over 93 hours. 93/37=2.5 hours

•At 175uA there were 32 trips over 90 hours.

•90/32=2.8 hours

•Trip pattern (size, stacks) changed, but frequency was not

•There are two outliers: South 3 and 4. May be 0 North/South too?


Pad with no track across it. Noise + scint light. All track crosses N=66226

Pure light signal between chan. 30 and 300. N_scint=433

Probability to get electron per track=433/66226=0.0065

This is first estimate:

Measurement with track trigger only across few pads, few others have no PIM track at the same time (no overlap with trigger counters):


Another pad with scint. Light and MIP track

Assume all signals with >300 correspond to MIP across this pad. N_mip=303 events

Look at other 3 pads (like ch10) where for sure was no any MIP at all – scint. counters were far away

For 3 pads with no tracks, we find only 14 scint. signals.

Probability to get light per pad will be (14/303)/3 pads= 0.0066

2nd test:

Probability to get electron from scintillation from track close to the pad is 0.006-0.007. This is the largest light signal.

Other tracks will give smaller probability


New resistor chain.

Zero voltage biasBias = +100 V (but low statistics)


Test Test stack’s stack’s voltagevoltage

Trip Trip setting setting above above nominalnominal

TRIP with TRIP with others?others?

2 kV2 kV 2 uA2 uA NONO No gainNo gain

3 kV3 kV 2 uA2 uA YESYES Very Very small gainsmall gain

3 kV3 kV 6 uA6 uA NONO *Interesti*Interestingng

3460V3460V 6 uA6 uA YESYES Operating Operating voltagevoltage

8/13/2008Detector Council Meeting1 HBD Status TK Hemmick for the HBD Crew.

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